*5.1.1 PANI nanocomposites for adsorption of heavy metals ions*

A PANI/RGO nanocomposite was reported by Li *et al*. [32] for the removal of Hg(II) ions from aqueous solution. It was shown that the PANI/RGO had high equilibrium adsorption capacity in comparison to PANI (**Figure 7a**). The obtained monolayer maximum adsorption capacity was 1000 mg/g at pH 4, 33°C and 400 mg/L for 200 mg adsorbent dose. Bhaumik *et al*. [38] reported a PANI/Fe0 nanocomposite for the removal of arsenic (As), which had Langmuir maximum adsorption capacity of 232.5 and 227.7 mg/g for both As(III) and As(V) at pH 7, 25°C and 1 mg/L for 10 mg of PANI/Fe0 nanocomposite. The obtained pH effects results (**Figure 7b**) showed higher removal efficiency by the nanocomposite in comparison to the neat PANI. Harijan and Chandra [33] reported a PANI/GO for the removal Cr(VI) from aqueous solution. It was demonstrated that the nanocomposite had high Langmuir maximum capacity of 192 mg/g at pH 6.5, 30°C and 100 mg/L for 25 mg of PANI/GO in comparison to the neat PANI (**Figure 7c**). **Table 2** shows some of the PANI nanocomposites reported for removal of various heavy metal ions under different experimental conditions.

### **5.2 Adsorption of organic dyes**

Organic pollutants are generally materials that comprise of aromatic rings in their structure. Numerous organic pollutants including dyes, chlorinated, aliphatic and phenolic compounds are carcinogenic and mutagenic [70]. Dyes are of major concern due to their wide application in textile, paper, pigment and plastic industries. Their presence in water systems results in water decolouration, which can

#### **Figure 7.**

*Comparison of PANI and PANI nanocomposites for the removal of various pollutants (a) kinetics [32], (b) pH effect [43], (c) isotherms [33] and (d) equilibrium adsorption capacity [34].*

**155**

**Table 3.**

*Polyaniline-Based Nanocomposites for Environmental Remediation*

**(mg/g)**

PANI/PAN Cr(VI) 67.03 2 5 10 [28] PAMpDA@Fe3O4 Co(II) 116.3 6 50 50 [69] PPy-PANI/Fe3O4 Cr(VI) 303.0 2 100 50 [3] Fe3O4/GO/PANI Cr(VI) 153.4 6.5 100 50 [47] PANI@Ni(OH)2 Cr(VI) 625.0 4 100 10 [2] PANI/zeolite Cr(VI) — 2 50 200 [48] PANI/PVP Mn(II) 50.30 7 100 250 [31]

**pH Conc.** 

**(mg/L)**

**Adsorbent dose (mg)**

**Refs.**

negatively affect aquatic life by influencing the photosynthetic process [71]. Some

Wang et al. [34] reported PANI/α-ZrP for the removal of methyl orange (MO) cationic dye. It was demonstrated by **Figure 7d** that the nanocomposite (5 mg) had high removal efficiency capacity at pH 4 and 25°C for 100 mg/L MO solution. The monolayer maximum adsorption capacity was obtained to be 377 mg/g. Tanzifi et al. [46] reported PANI/SiO2 nanocomposite for the removal of amido black 10B. The obtained Langmuir maximum adsorption capacity was 42.24 mg/g at pH 2, 25°C and 30 mg/L for a 100 mg adsorbent dose. Gharbani [37] reported PANI/tin(II)molybdophosphate for the removal of malachite green (MG). It was demonstrated that the removal efficiency was 93% for 50 mg/L of MG at pH 10 and the adsorption process followed Freundlich isotherm model. In another study, Ballav et al. [72] synthesised PANI coated ligno-cellulose composite (PLC) via in-situ polymerisation of aniline monomer for the removal of Reactive Black 5 (RB-5) from aqueous solutions. The authors reported that the equilibrium adsorption isotherm studies revealed that the Langmuir isotherm provided the best fit with monolayer adsorption capacity of 312 mg/g. The Maity's research group also reported the use of PANI-coated ligninbased adsorbent for the uptake of reactive dye eosin yellow (EY) from aqueous solution [73]. The adsorption capability of the adsorbent was found to be more effective

**(mg/g)**

PANI/MWCNTs CR 147 2 50 7 [74] PANI/PA 6 MO 48.8 — 10 30 [54]

PANI/CMC/TiO2 CR 94.28 2.6 82 140 [30] PANI/Fe0 CR 99.6 7 100 1000 [75] PPy–PANI NFs CR 222.22 4 200 1000 [35] Starch/PANI Reactive Black 5 811.30 5 10 60 [76]

**pH Conc. (mg/L)**

1000 2 10 500 [29]

**Adsorbent dose (mg)**

**Refs.**

of PANI based nanocomposites for dye removal are given in **Table 3**.

*5.2.1 PANI nanocomposites for adsorption of dyes*

*Some of the PANI nanocomposites for heavy metals adsorption.*

**Table 2.**

than the unmodified adsorbent at lower pH.

**Adsorbent Pollutant** *q***max**

RHB

*Some of the PANI based nanocomposites for dye adsorption.*

ZnFe2O4-PANI Rhodamine B

*DOI: http://dx.doi.org/10.5772/intechopen.82384*

**Adsorbent Pollutant** *q***max**


#### *Polyaniline-Based Nanocomposites for Environmental Remediation DOI: http://dx.doi.org/10.5772/intechopen.82384*

#### **Table 2.**

*Trace Metals in the Environment - New Approaches and Recent Advances*

*5.1.1 PANI nanocomposites for adsorption of heavy metals ions*

heavy metal ions under different experimental conditions.

biodegradable and can form various species [68].

25°C and 1 mg/L for 10 mg of PANI/Fe0

**5.2 Adsorption of organic dyes**

Heavy metals are problematic since they are mutagenic, carcinogenic, are not

A PANI/RGO nanocomposite was reported by Li *et al*. [32] for the removal of Hg(II) ions from aqueous solution. It was shown that the PANI/RGO had high equilibrium adsorption capacity in comparison to PANI (**Figure 7a**). The obtained monolayer maximum adsorption capacity was 1000 mg/g at pH 4, 33°C and 400 mg/L for 200 mg adsorbent dose. Bhaumik *et al*. [38] reported a PANI/Fe0 nanocomposite for the removal of arsenic (As), which had Langmuir maximum adsorption capacity of 232.5 and 227.7 mg/g for both As(III) and As(V) at pH 7,

results (**Figure 7b**) showed higher removal efficiency by the nanocomposite in comparison to the neat PANI. Harijan and Chandra [33] reported a PANI/GO for the removal Cr(VI) from aqueous solution. It was demonstrated that the nanocomposite had high Langmuir maximum capacity of 192 mg/g at pH 6.5, 30°C and 100 mg/L for 25 mg of PANI/GO in comparison to the neat PANI (**Figure 7c**). **Table 2** shows some of the PANI nanocomposites reported for removal of various

Organic pollutants are generally materials that comprise of aromatic rings in their structure. Numerous organic pollutants including dyes, chlorinated, aliphatic and phenolic compounds are carcinogenic and mutagenic [70]. Dyes are of major concern due to their wide application in textile, paper, pigment and plastic industries. Their presence in water systems results in water decolouration, which can

*Comparison of PANI and PANI nanocomposites for the removal of various pollutants (a) kinetics [32], (b) pH* 

*effect [43], (c) isotherms [33] and (d) equilibrium adsorption capacity [34].*

nanocomposite. The obtained pH effects

**154**

**Figure 7.**

*Some of the PANI nanocomposites for heavy metals adsorption.*

negatively affect aquatic life by influencing the photosynthetic process [71]. Some of PANI based nanocomposites for dye removal are given in **Table 3**.
