**Synthesis and Characterization of Arylazopyrazolopyrimidines Dyes and Studying their Antibacterial Activity**

K.A.Ahmed<sup>1</sup> , M. A. Elkashouti<sup>1</sup> , S.T.Tawfeek<sup>2</sup> and Sh. S. Mohamed<sup>1</sup>

1 Textile division, National Research Center, Cairo, Egypt

2 Faculty of applied art, Helwan University, Cairo, Egypt

#### **Abstract**

The purpose of this research is to synthesize several new pyrazolopyrimidine containing an arylazo function containing electron with drawing groups and benzothiazole moiety, the substituted 5-arylazopyrazolopyrimidine were prepared by reaction of aryl azopyrazole with airelidene of 2- cyanomethyl benzothiazole under basic condition in boiling ethanol. The structure of arylazopyrazolopyrimidine dyes were established by their element analysis and spectral data (MS, IR and 1 H-NMR). The antibacterial properties of these dyes have been investigated.

**Keywords:** pyrazolopyrimidine – benzothiazole – antibacterial activity

## **1. Introduction**

Innovations in azo dye based on heterocyclic systems have been made as a result of intensive studies stimulated by the mounting need for bright dyes. Generally many of heterocyclic azodyes show dramatic bathochromic shifts combined with brilliance of shade and high tinctorial strength compared with conventional anthraquinone dyes and aminobenzene azodyes[1-4]. In spite of the large number of arylazopyrazol dyes reported in literature, only very few condensed pyrazole derivatives carrying arylazo functions on the pyrazole ring have been reported, . In continuation of the increasing interest in synthesis of condensed arylazopyrazole new dyestuffs [3], the present work deals with novel synthesis of condensed arylazopyrazolopyrimidines derivatives and studying their printing properties using silk screen and heat transfer printing techniques on polyester and polyamide fabrics. The antibacterial activity of these dyes was also studied, where recently in the textile industrial sector [5], there has been increasing interest in the manufacture of clothing and products with antibacterial properties. Clothing of textile can act as carrier for microorganisms such as pathogenic or odor –generating bacteria and moulds [6]. The textile material is known to be susceptible to microbial attack, in contact with the human body it offers an ideal environment for microbial growth providing oxygen, water and warmth, and nutrients from spillages and body exudates [7]. This often leads to objectionable odor, dermal infection product deterioration, allergic responses and other related diseases which necessitate the development of clothing products with antimicrobial properties [8].

© 2012 Ahmed et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

## **2. Experlmental**

### **2.1. Synthesis of dyes**

#### *Preparation of 3,5 diamino-4-arylzopyrzole (1)*

(0.01 mole) of diazotized aniline derivatives coupled with (0.01 mole) of malono nitrite in the presence of (20 ml) ethanol and (5 gm) sodium acetate at 0-5˚C. The precipitated solid is filtrated and dried (0.01) mole of the dried solid is dissolved in (20 ml) ethanol then (0.01 mole) of hydrazine hydrate is added drop wise, the precipitated solid of arylazopyrazole derivatives is filtrated and re-crystallized from ethanol.

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**Dye number. Ar Ar1**

Melting points were measured by Electrothermal IA 9000 series digital melting point apparatus.

Elemental analytical data were obtained from the micro-analytical unit, National Research Cen-

Fourier- transition infrared spectroscopy (FTIR) was performed using a Pye-Unicam spectra-1000 machine to determine the functional groups on the surface of the linen samples. Potassium bro-

Mass spectra were measured on a Varian MAT CH-5 spectrometer (70 eV). 3.6 Spectrophotomet-

).

The NMR spectra were recorded on a Varian Mercury VX-300 NMR spectrometer. 1

were run at 300 MHz in deuterated dimethylsulphoxide(DMSO-*d6*

**4a**

**4b**

**4c**

**4e**

**4d**

**2.2. Measurements**

Melting point

*1*

Element analysis:

**Table 1.** Represents Ar and Ar1 groups

ter, Dokki, Giza, Cairo, Egypt.

mide (KBr) disc was used.

*H – NMR spectra:*

3.5 Mass spectra:

ric measurements:

Fourier-Transition Infrared Spectroscopy (FTIR):

Turkey, September 10-12, 2012

<sup>455</sup> ISALS

H spectra

*Preparation of* Cyanomethylarylidine benzothiazol-2-yl

Cyanomethylarylidinebenzothiazol-2-yl is prepared by the condensation reaction of (0.01 mole) of cyanomethyl benzothiol-2yl with (0.01) mole of aromatic aldehyde derivatives in (20 ml) ethanol and drops of piperidine at room temperature. The collected precipitate is filtrated and recrystallized in ethanol

General Procedure of synthesis of arylazo-pyrazolopyrimidines dyes:

To a solution of derivatives (1) (10 mmol) in ethanol (50 mL), the (2) (10 mmol) and drops of pipridine were added. The reaction mixture was refluxed for 4 h then left to cool. The formed product was filtered off, washed with ethanol, and recrystallized from ethanol to afford the corresponding arylzaopyrazolopyrimidines 4a-e. *(Scheme I)*

 **Scheme 1.**

**Table 1.** Represents Ar and Ar1 groups

#### **2.2. Measurements**

#### Melting point

Melting points were measured by Electrothermal IA 9000 series digital melting point apparatus. Element analysis:

Elemental analytical data were obtained from the micro-analytical unit, National Research Center, Dokki, Giza, Cairo, Egypt.

Fourier-Transition Infrared Spectroscopy (FTIR):

Fourier- transition infrared spectroscopy (FTIR) was performed using a Pye-Unicam spectra-1000 machine to determine the functional groups on the surface of the linen samples. Potassium bromide (KBr) disc was used.

#### *1 H – NMR spectra:*

The NMR spectra were recorded on a Varian Mercury VX-300 NMR spectrometer. 1 H spectra were run at 300 MHz in deuterated dimethylsulphoxide(DMSO-*d6* ).

3.5 Mass spectra:

Mass spectra were measured on a Varian MAT CH-5 spectrometer (70 eV). 3.6 Spectrophotometric measurements:

The absorbance of the dyes were measured in the ultraviolet -visible region at wave length between 300-700 nm. by a UNICAM UV spectrophotometer using a 1cm. quartz cell . The dyes were dissolved in absolute ethanol at a concentration of 10-4 mole/l.

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C; yield: (85%), IR (KBr), 3377-3328 (NH2

O exchangeable, 2H, NH2

, 499), Element analysis for C27H22N16SO2

The electronic absorption spectra of arylazopyr- azolopyrimidine dyes 4a-e have been studied,

Arylazopyrazolopyrimidine dyes have different resonating structures; the groups attached to

It is well known that, the stabilization of these dyes are effected by the substituents originates from the charge separation through the conjugated system between different substituents. However, stabilization of different resonating structures depends on the introduction of an electron – withdrawing group in the aromatic ring and electron donating group of the other aromatic ring. deep bathchromicshifts by the presence of (N,N-dimethyl ) as an electron donating group or as a rule the longer conjugation in the molecule; the deeper will be the color this is due to increase of the number of electron in the oscillation which facilities

It is clear from the results, in table (III) that all of the newly synthesized dyes (4a- e) with different color shades possess excellent inhibition of the bacteria growth against the tested gm positive and gm negative bacteria and the inhibition zone diameters obtained are in the range of (17-21) mm which is quite good compared to the control value of 0. It appears also that dyes (4b) and (4d) possessed relatively higher inhibition zone diameter value than the other dyes and this may be

polarizations , this phenomena is clear from the bathochromic shift of dye no. 4d גּ max=430

Esherichia

**Table 2.** Inhibition zone diameter of dyes (4a-e) against Gram positive and Gram negative bacteria

Coli (G- )

Tetracycline 30 30 30 30 Control 0.0 0.0 0.0 0.0 4a 19 20 19 19 4b 21 21 20 21 4c 17 20 19 19 4d 19 21 21 20 4e 17 18 17 19

orange crystals, m.p. ≥300°

ppm., MS (70 eV): *m*/*z* = 577 (M+

): *δ* 6.6 -7.7. (m, 4H, Ar-H), 8.00 (s, D2

C, 58.99 ; H, 4.00 ; N, 25.45 ; S, 5.81*.*; O, 5.81.

Found: C, 58.89 ; H, 4.00 ; N, 25.35 ; S, 5.71. ; O, 5.71.

**3.1. Electronic Effects and Ultraviolet-visible spectra**

rings play an important role in the resonance of the dyes.

**3.2. Antibacterial activity of the synthesized dyes**

Bacillus Subtilis (G+ )

attributed to its chemical structure and to the presence of Cl and NO2

Inhibition zone diameter (mm)

their UV spectrum was found to be ranging between 360-440 nm.

*d6*

Dye

Sample

Turkey, September 10-12, 2012

), cm-1, 1

), 4.00 (s, D2

<sup>457</sup> ISALS

)

H NMR (300 MHz, DMSO-

O exchangeable, 2H, NH2

molecular weight (577), Calc.:

groups in its structure [10].

Pseudomonea Aeuruginous

(G- )

Staphylococcus

Aureus (G+ )

### **2.3. Antibacterial activity measurements**

The newly synthesized pyrazolopyrimidines were assessed for their *in vitro* antibacterial activity in the Micro Analytical Centre of Cairo University using Kirby-bauer disc diffusion method [9].

## **3. Results and discussion**

The formation of 2,5-di-amino-3-arylazopyrazolopyrimidine ring system (4a-e) from compounds 1 and 2 under basic condition is assumed to proceed via addition of the most basic N atom in compound 1 to the unsaturated double bond in compound 2 to give the intermediate 3 this Michel adducts is followed by neuclophilic addition of NH2 group to CN group. The reaction was established and confirmed by studying their element analysis, and (IR –1 H-NMR – Mass) spectra. The following results were obtained

2,5-di-amino-3-(4-iodo)-arylazo-6-benzothiazol-2-yl-7-fur-2-yl-pyrazolopyrimidines ( 4a)

brown crystals, m.p. ≥300° C; yield: (85%)., IR (KBr), 3377-3328 (NH2 ), cm-1. , 1 H NMR (300 MHz, DMSO-*d6* ): *δ* 6.6-7.7. (m, 4H, Ar-H), 8.3 (s, D2 O exchangeable, 2H, NH2 ).,MS (70 eV): *m*/*z* = 577 (M+ , 576)., Element analysis for C23H15N8 SI molecular weight (576), Calc.: C, 47.83 ; H, 2.59; N,27.72 ; O, 10.77 ; S, 5.54. ; I, 22.01, Found: C, 47.73 ; H, 2.49 ; N, 27.62 ; O, 10.67 ; S, 5.44 ; I, 22.0 2,5-di-amino-3-(2,4-dichloro)-arylazo-6-benzothiazol-2-yl-7-thiophen-2-yl–pyrazolopyrimidine (4b)

Red crystals, m.p. ≥300° C; yield: (90%), IR (KBr), 3377-3328 (NH2 ), cm-1, 1 H NMR (300 MHz, DMSO*d6* ): *δ* 6.6-7.7. (m, 4H, Ar-H), 8.6 (s, D2 O exchangeable, 2H, NH2 ), MS (70 eV): *m*/*z* = 537 (M+ , 535),Element analysis for C23H14 N8 S2 Cl2 molecular weight (537), Calc.: C, 51.39 ; H, 2.60 ; N, 20.83 ; S, 11.91; Cl, 13.22*.,* Found: C, 51.29 ; H, 2.50 ; N, 20.73 ; S, 11.81; Cl, 13.21 2,5-di-amino-3-(4-nitro)-arylazo-6-(benzothiazol-2-yl)-7-phenylpyrazolopyrimidine (4c)

yellow crystals, m.p. ≥300° C; yield: (85%), IR (KBr), 3377-3328 (2NH2 ), cm-1, 1 H NMR (300 MHz, DMSO-*d6* ): *δ* 6.6-7.7. (m, 4H, Ar-H), 8.3 (s, D2 O exchangeable, 2H, NH2 ), MS (70 eV): *m*/*z* = 505 (M+ , 504), Element analysis forC25H17N9 SO2 molecular weight (505), Calc.: C, 59.40; H, 3.36 ; N, 24.25 ; S, 6.33; O, 6.33, Found: C, 59.30 ; H, 3.26 ; N, 24.15 ; S, 6.23; O, 6.23.

2,5-di-amino - 3-(2-chloro - 4 - nitro) - arylazo - 6 - benzothiazol - 2 - yl) - 7 - (thiophen-2yl) pyrazoloPyri midine (4d)

brown crystals, m.p. ≥300° C; yield: (85%), IR (KBr), 3377-3328 (2NH2 ) , cm-1, 1 H NMR (300 MHz, DMSO-*d6* ): *δ* 6.6-7.7. (m, 4H, Ar-H), 8.1 (s, D2 O exchangeable, 2H, NH2 ),MS (70 eV): *m*/*z* = 547 (M + , 546), Element analysis for C23H14N9 S2 O2 Cl molecular weight (547), Calc. : C, 50.45 ; H, 2.55 ; N, 23.03 ; S,11.70*.* ; O, 5.85; Cl, 6.39, Found : C, 50.3 ; H, 2.45 ; N, 23.0 ; S,11.60 ; O, 5.75 ; Cl, 6.29.

2,5-di-amino-3-(4-nitro)-arylazo-6-(benzothiazol-2-yl)-7-(4-(dimethylamino)phenyl)Pyrazolo pyrimidine (4e)

orange crystals, m.p. ≥300° C; yield: (85%), IR (KBr), 3377-3328 (NH2 ), cm-1, 1 H NMR (300 MHz, DMSO*d6* ): *δ* 6.6 -7.7. (m, 4H, Ar-H), 8.00 (s, D2 O exchangeable, 2H, NH2 ), 4.00 (s, D2 O exchangeable, 2H, NH2 ) ppm., MS (70 eV): *m*/*z* = 577 (M+ , 499), Element analysis for C27H22N16SO2 molecular weight (577), Calc.: C, 58.99 ; H, 4.00 ; N, 25.45 ; S, 5.81*.*; O, 5.81.

Found: C, 58.89 ; H, 4.00 ; N, 25.35 ; S, 5.71. ; O, 5.71.

#### **3.1. Electronic Effects and Ultraviolet-visible spectra**

The electronic absorption spectra of arylazopyr- azolopyrimidine dyes 4a-e have been studied, their UV spectrum was found to be ranging between 360-440 nm.

Arylazopyrazolopyrimidine dyes have different resonating structures; the groups attached to rings play an important role in the resonance of the dyes.

It is well known that, the stabilization of these dyes are effected by the substituents originates from the charge separation through the conjugated system between different substituents. However, stabilization of different resonating structures depends on the introduction of an electron – withdrawing group in the aromatic ring and electron donating group of the other aromatic ring. deep bathchromicshifts by the presence of (N,N-dimethyl ) as an electron donating group or as a rule the longer conjugation in the molecule; the deeper will be the color this is due to increase of the number of electron in the oscillation which facilities polarizations , this phenomena is clear from the bathochromic shift of dye no. 4d גּ max=430

## **3.2. Antibacterial activity of the synthesized dyes**

It is clear from the results, in table (III) that all of the newly synthesized dyes (4a- e) with different color shades possess excellent inhibition of the bacteria growth against the tested gm positive and gm negative bacteria and the inhibition zone diameters obtained are in the range of (17-21) mm which is quite good compared to the control value of 0. It appears also that dyes (4b) and (4d) possessed relatively higher inhibition zone diameter value than the other dyes and this may be attributed to its chemical structure and to the presence of Cl and NO2 groups in its structure [10].


**Table 2.** Inhibition zone diameter of dyes (4a-e) against Gram positive and Gram negative bacteria

Different novel functionalized 2, 5-di-amino-3-arylazopyrazolopyrimidines derivatives (4a-e) are prepared in good yield as well as good antibacterial properties.

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**Synthesis of Partially Carboxymethyl Cellulose** 

, H. M. El-Hennawi<sup>2</sup>

**Derived from Rice Straw and Its Utilization as** 

2 Dyeing, Printing and textile auxiliaries Department, Textile Research Division, National

Two samples of partially carboxymethyl cellulose derivatives of different D.S. values were prepared from Egyptian rice straw via pulping followed etherification using different concentrations of monochloro acetic acid under the catalytic action of sodium hydroxide. The prepared derivatives were assessed for D.S. and evaluated as dye adsorbent for different classes of dyestuff. The results obtained indicate that, the D.S. increases from 0.09 to 0.14 by increasing monochloro acetic acid from 5 to 10 g/100g cellulose pulp. The rate of dye absorbance increases by increasing the amount of adsorbent as well as the time of adsorption. While as the dye concentration increases from 0.01 to 0.5 the percent dye absorption decrease regularly. However, the magnitude of the percent decrease in the colour depends on : (a) the nature of the dyestuff used ,(b) the D.S. of the adsorbent, and (c) on the technique applied . The magnitude of colour removal in case of using ultrasonic technique is relatively higher than the mechanical shaking irrespective of the nature of the dye used and/or the conditions of adsorbance. The percent colour removal follows

**Dye Adsorbent**

I. Abd El-Thalouth<sup>2</sup>

Research Centre, Cairo,Egypt

, S. H. Abd Elsalam<sup>1</sup>

1 Faculty of Applied Arts, Helwan University, Cairo, Egypt

, E. Adel<sup>1</sup>

S. Tawfik1

**Abstract**

**1. Introduction**

© 2012 Tawfik et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the

original work is properly cited.

the order Basic green> Basic yellow> Acid green> Acid blue respectively.

**Keywords:** rice straw- colour removal-ultrasonic- adsorption-carboxymethylation

Rice is the largest cereal crop in the world. Rice straw represents around 45% of the volume in rice production, producing the largest quantity of crop residue. As rice straw is a marginal feed compared to other cereal grain straw and a problematic fuel source due to high ash generation, exploring more viable options to utilize rice straw is pressing, particularly as an environmental concern. With its compositions of cellulose (38.3%), hemicellulose (31.6%), lignin (11.8%) and silica (18.3%) [1] rice straw is the most available cellulose source from agricultural crop residues in the world[2] In recent years, many biological materials, such as orange bagasse [3], plant leaves [4], saw dust [5] and maize cob [6], have been applied as adsorbents to adsorb dyes from wastewaters. Researchers have been trying to find ways to take advantages of straw [7,8]. One of the promising ways to use this precious bioresource is to produce straw-based adsorbents

Turkey, September 10-12, 2012

,

<sup>459</sup> ISALS

#### **4. References**


## **Synthesis of Partially Carboxymethyl Cellulose Derived from Rice Straw and Its Utilization as Dye Adsorbent**

S. Tawfik1 , S. H. Abd Elsalam<sup>1</sup> , H. M. El-Hennawi<sup>2</sup> , I. Abd El-Thalouth<sup>2</sup> , E. Adel<sup>1</sup>

1 Faculty of Applied Arts, Helwan University, Cairo, Egypt 2 Dyeing, Printing and textile auxiliaries Department, Textile Research Division, National

Research Centre, Cairo,Egypt

#### **Abstract**

Two samples of partially carboxymethyl cellulose derivatives of different D.S. values were prepared from Egyptian rice straw via pulping followed etherification using different concentrations of monochloro acetic acid under the catalytic action of sodium hydroxide. The prepared derivatives were assessed for D.S. and evaluated as dye adsorbent for different classes of dyestuff. The results obtained indicate that, the D.S. increases from 0.09 to 0.14 by increasing monochloro acetic acid from 5 to 10 g/100g cellulose pulp. The rate of dye absorbance increases by increasing the amount of adsorbent as well as the time of adsorption. While as the dye concentration increases from 0.01 to 0.5 the percent dye absorption decrease regularly. However, the magnitude of the percent decrease in the colour depends on : (a) the nature of the dyestuff used ,(b) the D.S. of the adsorbent, and (c) on the technique applied . The magnitude of colour removal in case of using ultrasonic technique is relatively higher than the mechanical shaking irrespective of the nature of the dye used and/or the conditions of adsorbance. The percent colour removal follows the order Basic green> Basic yellow> Acid green> Acid blue respectively.

**Keywords:** rice straw- colour removal-ultrasonic- adsorption-carboxymethylation

#### **1. Introduction**

Rice is the largest cereal crop in the world. Rice straw represents around 45% of the volume in rice production, producing the largest quantity of crop residue. As rice straw is a marginal feed compared to other cereal grain straw and a problematic fuel source due to high ash generation, exploring more viable options to utilize rice straw is pressing, particularly as an environmental concern. With its compositions of cellulose (38.3%), hemicellulose (31.6%), lignin (11.8%) and silica (18.3%) [1] rice straw is the most available cellulose source from agricultural crop residues in the world[2] In recent years, many biological materials, such as orange bagasse [3], plant leaves [4], saw dust [5] and maize cob [6], have been applied as adsorbents to adsorb dyes from wastewaters. Researchers have been trying to find ways to take advantages of straw [7,8]. One of the promising ways to use this precious bioresource is to produce straw-based adsorbents

© 2012 Tawfik et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

[9-13]. However, the adsorption capacity of unmodified straw is insignificant, since straw materials are deficient in free ionic groups, which would play an important role in removal of ionic dyes. Therefore, it could improve the adsorption capacity of straw by introducing some ionic functional groups through chemical modification [14]. Lilienfeld [15,16], was the first to affect the partial carboxymethylation of cotton. Two main methods for the preparation of partially carboxymethylated cellulose are known:(a)The aqueous carboxymethylation and (b)The non aqueous carboxymethylation. Partially carboxymethylated cellulose with a D.S. of about 0.05 to 0.15 retains the original fibrous nature and exhibits a number of potentially valuable properties. The objective of this paper is to synthesize two different partially carboxymethylated derivatives from Egyptian rice straw pulp and to investigate their suitability to be utilized these derivatives as adsorbent substrates for different reactive dyes under a variety of conditions.

#### **2. Materials and Methods**

#### **2.1. Native rice straw supplied by Racta Co. For Paper Manufacture, Alexandria, was used**

The following different dyes selected from the most dyestuffs which are used in the Egyptian Textile Industry.


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Sodium hydroxide and So dium hypochlorite both of laboratory grad e chemicalss were also

The alkali treated sample wer e subjected to sodium hypochloritte (NaOCl) bleaching (4g/l active chlorine) for two hours at room temperature, liquor ratio 10:1 foll owed by waashing thoro-

Two different substituted partially carboxymethylated rice straw derivatives were prepared from bleached rice straw via using different concentrations of the etherifying agents, i.e. monochloro acetic acid and sodium hydroxide. The procedure adopted was carried out as follows:

Alkali cellulose was prepared by treating 100g of dry bleached rice straw with 200 ml of 5% aqueous sodium hydroxide solution, and mixed well, a solution of 5g monochloro acetic acid in 100ml distilled water was added gradually to the alkali cellulose with continuous agitation for two hours, and the reaction mixture was left at room temperature overnight. The excess alkali was neutralized with glacial acetic acid using phenolphthalein as indicator. At this end the product was filtrated washed well with water and finally air dried at ambient conditions. Another sample was also prepared by the same technique using 10% sodium hydroxide solution and 10g

Different amount of different substrate ( rice straw, alkali treated and rice straw pulp) were added to aqueous solutions of the selected dyes (0.01g) dissolved in 1 liter of distilled water. The suspension was treated using either mechanical shaking or ultrasonic technique for different periods of time (5, 15, 30, 45, 60 minutes)and temperatures (30, 40, 50, 60°C). At the end of the run of aliquot was centrifuged at5000 rpm for 30 min and the dye concentration in the clear solution was evaluated colourimetrically at the maximum wavelength for every dyestuff. The absorbance was measured using a double-beam spectrophotometer Thermo Electron Corporation Unican

used.

**2.2. Methods:**

*2.2.1. Preparationn of bleached rice straw:*

oughly with running w ater and finally air dried.

monochloro acetic acid dissolved in 100ml water

**2.3. Procedure of Dye Adsorption**

300, England.

*2.2.2. Preparationn of partially carboxymethyl ric e straw derivatives:*

Turkey, September 10-12, 2012

<sup>461</sup> ISALS

Sodium hydroxide and So dium hypochlorite both of laboratory grad e chemicalss were also used.

#### **2.2. Methods:**

#### *2.2.1. Preparationn of bleached rice straw:*

The alkali treated sample wer e subjected to sodium hypochloritte (NaOCl) bleaching (4g/l active chlorine) for two hours at room temperature, liquor ratio 10:1 foll owed by waashing thorooughly with running w ater and finally air dried.

#### *2.2.2. Preparationn of partially carboxymethyl ric e straw derivatives:*

Two different substituted partially carboxymethylated rice straw derivatives were prepared from bleached rice straw via using different concentrations of the etherifying agents, i.e. monochloro acetic acid and sodium hydroxide. The procedure adopted was carried out as follows:

Alkali cellulose was prepared by treating 100g of dry bleached rice straw with 200 ml of 5% aqueous sodium hydroxide solution, and mixed well, a solution of 5g monochloro acetic acid in 100ml distilled water was added gradually to the alkali cellulose with continuous agitation for two hours, and the reaction mixture was left at room temperature overnight. The excess alkali was neutralized with glacial acetic acid using phenolphthalein as indicator. At this end the product was filtrated washed well with water and finally air dried at ambient conditions. Another sample was also prepared by the same technique using 10% sodium hydroxide solution and 10g monochloro acetic acid dissolved in 100ml water

#### **2.3. Procedure of Dye Adsorption**

Different amount of different substrate ( rice straw, alkali treated and rice straw pulp) were added to aqueous solutions of the selected dyes (0.01g) dissolved in 1 liter of distilled water. The suspension was treated using either mechanical shaking or ultrasonic technique for different periods of time (5, 15, 30, 45, 60 minutes)and temperatures (30, 40, 50, 60°C). At the end of the run of aliquot was centrifuged at5000 rpm for 30 min and the dye concentration in the clear solution was evaluated colourimetrically at the maximum wavelength for every dyestuff. The absorbance was measured using a double-beam spectrophotometer Thermo Electron Corporation Unican 300, England.

The percent dye absorption was calculated by equation 1 :

$$\% \text{ Column removal} = \frac{\text{CA of original sample} - \text{CA of treated sample}}{\text{CA for the origin}} \times 100$$

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Generally speaking it is clear from the Figures 1 and 2 that increasing the amount of adsorbent, i.e. partially carboxymethyl derivatives, is accompanied by an increase in the % colour removal to reach to a maximum after which it either remain constant or decreases. This phenomenon holds true regardless of (a) the D.S.,(b) the nature of the reactive dye used, or (c) the technique applied. It is also clear from the figures that in case of the samples conducted via mechanical shaking the %dye adsorption of the carboxymethyl derivative of relatively low D.S. (0.09) is higher than their corresponding samples acquire relatively higher D.S. (0.14) this phenomenon is true on using either reactive violet5 or reactive blue19. While, in case of ultrasonic, there is irregularity in the results. It seems that the sample of partially carboxymethylated derivative prepared using 5g monochloro actic acid acquire the sufficient carboxymethyl groups to open the structure of cellulose and hence its absorbance reach to the maximum. Increasing the D.S. causes an increase

crease in the negative charge on the substrate. Since the reactive dye acquire negative charge too hence the rate of dye adsorption decrease. It is also observed that ultrasonic technique increases the absorbance capacity of both carboxymethyl derivatives under investigation since they are higher than their corresponding samples conducted via mechanical stirring. For example the % colour removal for the relatively higher D.S. (0.14) derivative on using reactive blue19 was 86.6%

mechanical shaking respectively. Furthermore, it is clear from the data that, irrespective of the amount of the adsorbent or the technique applied, Partially carboxymethylated samples acquire higher % colour removal compared with the native, alkali treated and the pure cellulose, i.e. alkali treated and bleached samples.

Figures 3 and 4 represent the data obtained on studying the effect of time of adsorption of different reactive dyes, on using two carboxymethylation derivatives of different D.S. values 0.09 and 0.14 respectively.

**Fig 1.** Effect of amount of carboxymethyl cellulose derivative of D.S. 0.09 on % colour removal using different reactive dyes reactive dyes for (a) ultra-

of the COOH groups. The latter ionize in the solution into-COO¯

against 62.2% for the sample conducted using ultrasonic and

**3.2. Effect of Treatment Time**

sonic and (b shaking treatment.

Turkey, September 10-12, 2012

**Fig 2.** Effect of amount of carboxymethyl derivative of D.S. 0.14on % colour removal using different reactive dyes for (a) ultrasonic and (b shaking treatment

and Na⁺

which causes an in-

<sup>463</sup> ISALS

Where CA is the colour absorbance

#### *2.3.1. Determination of degree of substitution (D.S.)*

The D.S. was determined according to a standard method [17]. Where The water soluble sodium carboxymethyl cellulose is converted to the insoluble acid form, purified by washing, dried and then a weight sample is reconverted to the sodium salt with a measured excess of sodium hydroxide from which the D.S was calculated.

#### **3. Results and discussion**

Pure cellulose was prepared from rice straw wastes via alkali scouring and bleaching as previously mentioned. The prepared cellulose was subjected to carboxymethylation using two different amounts of the etherifying agents i.e. monochloro acetic acid and sodium hydroxide. The caroxymethelation reaction took place according to the following reaction:

#### Cell.OH + Cl.CH2 .COOH + 2 NaOH → Cell.O.CH2 COONa + NaCl + 2 H2 O

Table 1 represent the effect of concentration of monochloro acetic acid on the D.S. of the prepared partially carboxymethyl cellulose derivatives.


**Table 1.** The effect of the amount of monochloro acetic acid on the D.S. of the prepared derivatives

It is clear from the data of Table I that the degree of substitution (D.S.) depends on the concentration of the etherfying agent i.e. monochloro acetic acid.As the latter increases from 5 to 10 g/100 pure cellulose, the D.S. increases from 0.09 to 0.14 respectively.It is also clear from Table I that the prepared partially carboxymethylated bleached rice straw is insoluble in both water and ethyl alcohol.

#### **3.1. Effect of amount of partially carboxymethyl cellulose on dye adsorbents**

The prepared two partially carboxymethylated cellulose derived from rice straw was utilized as dye adsorbent for both reactive blue19 and reactive violet5. Figure 1and 2 represent the data obtained on using the two partially carboxymethyl cellulose derivative of different D.S.values on conducting the adsorbance using mechanical shaking or ultrasonic technique.

sonic and (b shaking treatment.

**Fig 2.** Effect of amount of carboxymethyl derivative of D.S. 0.14on % colour removal using different reactive dyes for (a) ultrasonic and (b shaking treatment

Generally speaking it is clear from the Figures 1 and 2 that increasing the amount of adsorbent, i.e. partially carboxymethyl derivatives, is accompanied by an increase in the % colour removal to reach to a maximum after which it either remain constant or decreases. This phenomenon holds true regardless of (a) the D.S.,(b) the nature of the reactive dye used, or (c) the technique applied. It is also clear from the figures that in case of the samples conducted via mechanical shaking the %dye adsorption of the carboxymethyl derivative of relatively low D.S. (0.09) is higher than their corresponding samples acquire relatively higher D.S. (0.14) this phenomenon is true on using either reactive violet5 or reactive blue19. While, in case of ultrasonic, there is irregularity in the results. It seems that the sample of partially carboxymethylated derivative prepared using 5g monochloro actic acid acquire the sufficient carboxymethyl groups to open the structure of cellulose and hence its absorbance reach to the maximum. Increasing the D.S. causes an increase of the COOH groups. The latter ionize in the solution into-COO¯ and Na⁺ which causes an increase in the negative charge on the substrate. Since the reactive dye acquire negative charge too hence the rate of dye adsorption decrease. It is also observed that ultrasonic technique increases the absorbance capacity of both carboxymethyl derivatives under investigation since they are higher than their corresponding samples conducted via mechanical stirring. For example the % colour removal for the relatively higher D.S. (0.14) derivative on using reactive blue19 was 86.6% against 62.2% for the sample conducted using ultrasonic and

mechanical shaking respectively. Furthermore, it is clear from the data that, irrespective of the amount of the adsorbent or the technique applied, Partially carboxymethylated samples acquire higher % colour removal compared with the native, alkali treated and the pure cellulose, i.e. alkali treated and bleached samples.

#### **3.2. Effect of Treatment Time**

Figures 3 and 4 represent the data obtained on studying the effect of time of adsorption of different reactive dyes, on using two carboxymethylation derivatives of different D.S. values 0.09 and 0.14 respectively.

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**Fig 5.** Effect of dye concentration on % colour removal using carboxymethyl derivative of D.S.0.09 (a) ultra-

of the dye molecules as the concentration increases.

in case of using mechanical shaking and ultrasonic.

(a) ultrasonic and (b shaking treatment)

**3.4. Effect of nature of the dyestuff used**

sonic and (b shaking treatment

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**Fig 6.** Effect of dye concentration on % colour removal using carboxymethyl derivative of D.S.0.14

(a) ultrasonic and (b shaking treatment

It is clear from the data that in all cases as the dye concentration increases from 0.01 to 0.5gm, % the percent dye adsorption decreases regularly. This may be due to either: (a) aggregation of the dye molecules which increases as the concentration increases, or (b) the decrease in the mobility

At the end, it is of great interest to investigate the effect of the nature of the dyestuffs used on the percent colour removal on using carboxy methyl cellulose derivatives derived from rice straw of D.S. 0.09 and 0.14. Hence 4different dyestuffs (two of them acid and the other are basic) were chosen and used with the mentioned carboxymethyl cellulose derivatives under identical conditions in case of either mechanical shaking or ultrasonic. The results obtained are illustrated in Figure 7

**Fig 7.** Effect of nature of dyestuff on the ability of carboxymethyl derivatives towards colour removal on using

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**Fig 3.** Effect of treatment time using carboxymethyl cellulose derivative of D.S. 0.09 on % colour removal using different reactive dyes for (a) ultrasonic and (b shaking treatment

**Fig 4.** Effect of treatment time using carboxy- methyl cellulose derivative of D.S.0.14 on % colour removal using different reactive dyes for (a) ultrasonic and (b shaking treatment

Generally speaking, it is clear from figures 3& 4 that in all cases the rate of dye adsorption increases by increasing the time of adsorption to reach to a maximum after which it shows slight decrease or remains constant. However, the time of adsorption to reach the maximum value and magnitude of the % colour removal at the maximum adsorption depends on the nature of the colour and the adsorbent used as well as the technique applied.It is clear that for the samples conducted via mechanical shaking the maximum dye adsorption was obtained after 45minutes irrespective of the D.S. of carboxymethyl sample or the nature of the reactive dye used, where, it reaches to 78.9% and 48.9% on using reactive violet5 and 76.6% and 62.2% on using reactive blue19 for carboxymethyl samples of D.S. 0.09 and 0.14 respectively. In other words, the sample of low D.S. acquires a higher absorbance capacity than the sample which acquire relatively higher D.S. While, in case of using ultrasonic technique the maximum dye adsorption arrived at relatively lower time, i.e. 30minutes only. However, the magnitude of the maximum dye adsorption was higher for carboxymethyl derivative of relatively low D.S. value only on using reactive violet5. While in case of using reactive blue19, the opposite holds true. The decreases in the % colour removal on using carboxymethyl derivative of relatively higher D.S. value may be due to the increase in the negatively charged (-COO- ) groups on the polymer. The latter repel the reactive dye molecules which acquire the similar negative charge as previously explained. Hence, the numbers of the adsorbed dye molecules decreases.

#### **3.3. Effect of Dye Concentration**

Figures 5and 6 represent the results obtained on using different concentrations of the aforementioned two different reactive dyes in case of carboxymethyl derivatives of D.S. 0.09 and 0.14 respectively.

**Fig 5.** Effect of dye concentration on % colour removal using carboxymethyl derivative of D.S.0.09 (a) ultrasonic and (b shaking treatment

**Fig 6.** Effect of dye concentration on % colour removal using carboxymethyl derivative of D.S.0.14 (a) ultrasonic and (b shaking treatment

It is clear from the data that in all cases as the dye concentration increases from 0.01 to 0.5gm, % the percent dye adsorption decreases regularly. This may be due to either: (a) aggregation of the dye molecules which increases as the concentration increases, or (b) the decrease in the mobility of the dye molecules as the concentration increases.

#### **3.4. Effect of nature of the dyestuff used**

At the end, it is of great interest to investigate the effect of the nature of the dyestuffs used on the percent colour removal on using carboxy methyl cellulose derivatives derived from rice straw of D.S. 0.09 and 0.14. Hence 4different dyestuffs (two of them acid and the other are basic) were chosen and used with the mentioned carboxymethyl cellulose derivatives under identical conditions in case of either mechanical shaking or ultrasonic. The results obtained are illustrated in Figure 7 in case of using mechanical shaking and ultrasonic.

**Fig 7.** Effect of nature of dyestuff on the ability of carboxymethyl derivatives towards colour removal on using (a) ultrasonic and (b shaking treatment)

Generally speaking it is obvious from the figure 7 that the % decreases in colour depends on: (a) the nature of the dyestuff used, (b) the D.S. of the adsorbent and, (c) on the technique applied. It is also clear on using carboxymethyl derivative of D.S. (0.09) for the samples conducted under mechanical shaking the % colour removal in case of basic dyes is higher than that of acid dye. The percent colour removal

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[7] P. Binod, R. Sindhu, R.R. Singhania, S. Vikram, L. Devi, S. Nagalakshmi, N. Kurien, R.K. Sukumaran, A. Pandey, Bioethanol production from rice straw: an overview, Bioresour. Technol.

[8] F.A. Abdel-Mohdy, E.S. Abdel-Halim, Y.M. Abu-Ayana, S.M. El-Sawy, Rice straw as a new

[9] U. Farooq, J.A. Kozinski, M.A. Khan, M. Athar, Biosorption of heavy metal ions using wheat based biosorbents—a review of the recent literature, Bioresour. Technol. 101 (2010) 5043–5053. [10] H. Muhamad, H. Doan, A. Lohi, Batch and continuous fixed-bed column biosorption of Cd2+

[11] B.C. Oei, S. Ibrahim, S. Wang, H.M. Ang, Surfactant modified barley straw for removal of acid and reactive dyes from aqueous solution, Bioresour. Technol. 100 (2009) 4292–4295.

[12] S. Ibrahim, I. Fatimah, H.M. Ang, S.B. Wang, Adsorption of anionic dyes in aqueous solution

[13] S. Ibrahim, W.Z. Shuy, H.M. Ang, S.B. Wang, Preparation of bioadsorbents for effective adsorption

[14] R.P. Han, L.J. Zhang, C. Song, M.M. Zhang, H.M. Zhu, L.J. Zhang, Characterization of modified wheat straw, kinetic and equilibrium study about copper ion and methylene blue adsorption in

[15] L. liliendfeld, Brit. Patent , 231, 803 (1924); C.A. 19,3600 (1925). [16] L. liliendfeld, Brit. Patent, 231,

[16] M. El-Zawahry, Ph.D. Thesis "Utilization of some carbohydrate derivatives in dye adsorption to

using chemically modified barley straw, Water Sci. Technol. 62 (2010) 1177–1182.

of a reactive dye in aqueous solution, Asia-Pac. J. Chem. Eng. 5 (2010) 563–569.

minimize dyestuff pollution" Faculty of science , Cairo University (1995).

resource for some beneficial uses, Carbohydr. Polym. 75 (2009) 44–51.

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cellulose derivatives acquire (- ve) charges. Hence, it is expected that the capacity for dye adsorbtion of carboxymethyl cellulose derivatives is higher on using basic dyes than using acid dyes. It is clear from figure 7 that for basic dyestuffs used the % colour removal is higher on using carboxymethyl cellulose of relatively D.S. (0.14) values than their corresponding samples conducted using relatively D.S. (0.09) derivative. This due to the increases in the (- ve) charge of adsorbent as the D.S. increase. The same trend could be observed for the samples conducted via ultrasonic technique. Furthermore, it is clear that on using acid dyestuffs either blue or green the % colour removal decreases by increasing the D.S. of carboxymethyl derivatives from 0.09 to 0.14. As the D.S. increases the (- ve) charges increases and hence the adsorbed acid dye which acquire (- ve) charges decrease.

#### **4. Conclusion**

The percent colour removal increases by increasing the time of treatment and / or the amount of substrate. While the opposite holds true by increasing the dye concentration. In all cases the magnitude of dye adsorption in case of ultrasonic is relatively higher than mechanical shaking. Increasing D.S of carboxymethyl derivatives decrease the % colour removal of reactive dye . The percent colour removal depends on the nature of dye used and follows the order Basic green> Basic yellow> Acid green> Acid blue respectively.

#### **5. References**


*Edited by Farhad Nejadkoorki*

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*Edited by Farhad Nejadkoorki*