**7.4 Removal of lead**

Various activities such as finishing of tools, steel and cable reclamation, manufacturing of plastics, formation of cathode ray tubes, ceramics and soldering are the major sources of lead discharge into the environment [89]. Large exposure of lead results in various harmful biological effects and it strongly binds itself with the particles of oil, sediments, and sewage sludge due to which its removal has gained much attention. Various types of agro/food waste materials have been used for the removal of lead such as orange peel, chitosan, rice husk, walnut shells, peanut, lemon grass *(Cymbopogoncitratus)*, groundnut (*Arachishypogaea)*,


**139**

*Potential Use of Agro/Food Wastes as Biosorbents in the Removal of Heavy Metals*

*Performance of several agricultural wastes for the removal of toxic metal ions.*

Zn (II) Coir fiber >70% [83]

Black gram husk Near about

Bagasse Near about

**Agro/Food Waste Adsorption Capacity** 

Cr (VI) Almond shell 3.40 [85]

Cd (II) Rice husk 73.96 [98]

**Agro/Food Waste Efficiency References**

Defatted rice bran 87% [78] Rice bran >80% [55]

Papaya wood 67% [58]

Banana peel 131.56 [14] Walnut shell 1.33, 8.01 [85] Hazelnut shell 8.28 [85] Coconut waste (puresorbe) 285.70 [30]

Nut shell 1.47 [92] Pea waste 21.2 [93] Saw dust 10.01, 16.05 [20] Pinusroxburghii bark 4.15 [94] Groundnut husk 7.0 [95] Bael fruit 17.27 [96]

Wheat bran (Chemically modified) 93.00 [16]

Wheat bran 310.58 [28] Groundnut husk (Ag coated) 11.40 [95] Wheat straw (Chemically modified) 322.58 [97]

Wheat straw 21.34 [97]

Banana peel 35.52, 5.71 [99, 100]

Wheat bran 22.78, 21.00, 15.82 [101, 102]

Wheat straw 39.22, 21.00,14.56, 11.60 [103, 104]

Rice husk (H3PO4 treated) 102.00 [47]

Wheat bran (Ultrasonic treated) 51.58 [102]

Wheat straw (Urea treated) 4.25 [103] Orange peel 47.60 [105] Mango peel 68.92 [106] Tea waste 11.29 [35] Rice husk (Alkali treated) 125.94 [98] Orange peel (chemically modified) 136.05 [105] Raw coffee powder 15.65 [35]

**(mg/g)**

93%

95%

[63]

[53]

**References**

*DOI: http://dx.doi.org/10.5772/intechopen.94175*

**Heavy Metal Ion**

**Table 1.**

**Toxic Metal Ions**

*Potential Use of Agro/Food Wastes as Biosorbents in the Removal of Heavy Metals DOI: http://dx.doi.org/10.5772/intechopen.94175*


#### **Table 1.**

*Emerging Contaminants*

**Agro/Food Waste Efficiency References**

Bagasse 90–95% [53]

Rice bran >80% [55] Black gram husk 99% [56] Rice husk 80–97% [57] Papaya wood 98% [58] Wheat bran 87.15% [59] Rice polish >90% [59] Bagasse fly ash 90% [60]

Waste tea leaves 92% [12] Apple residue waste Nearly 80% [61] *Orizasativa* husk 98% [62] Black gram husk Nearly 93% [63] Maple saw dust 80–90% [64] Saw dust of rubber wood 85% [35] Activated carbon of peanut shells Nearly 75% [65]

Raw rice bran 40–50% [67] Rubber wood saw dust 60–70% [68] Beech saw dust 100% [69] Coconut shell fibers >80% [70] Neem leaf powder >96% [71] Bagasse fly ash 96–98% [72]

*Casia fistula* biomass 100% [73] Saw dust of oak 70–90% [74] black gram husk Nearly 93% [63] Tea waste 86% [75] Maple saw dust 75% [76] Waste tea leaves 92% [12] Mustard oil cake Nearly 94% [77] Defatted rice bran 57% [78]

Wheat shell 99% [80]

Rice hush Nearly 71% [82]

Up to 97% [9]

Green coconut shell powder 98% [54]

Cd (II) Wheat bran >82% [16]

Pb (II) Rice bran >80% [55]

Cr (III) Oat biomass >80% [66]

Cr (VI) Wheat bran >82% [16]

Ni (II) Sugarcane bagasse >80% [9]

Cu (II) Mango saw dust 60% [79]

As (III) Charred saw dust 80% [81]

Jatropha oil cake, maize corn cob and sugarcane bagasse,

**Heavy Metal Ion**

**138**

*Performance of several agricultural wastes for the removal of toxic metal ions.*



#### **Table 2.**

*Biosorption capacities of different agricultural waste and plant products for the eradication of toxic metal ions.*

and coir pith waste of coconut [15, 89]. The absorption capacity of coir pith waste of coconut and chitosan is found to be 263.0 mg/g and 8.3 mg/g respectively as shown in **Table 2** [90, 91]. Biosorption capacities of various other agro/food wastes against the removal of toxic heavy metal ions are presented in **Table 2**.

#### **8. Conclusions**

The existing physical and chemical methods for the removal of heavy metals have severe limitations such as they require various chemicals, are energy intensive, costly to operate, produce large quantities of sludge whose disposal is a big problem etc. Therefore, there is a need of some alternative method which can attractively remove the toxic metal ions in the best possible way. In this regard biosorption is an attractive alternative method to remove the toxic metal ions effectively from

**141**

**Author details**

Faizan Ahmad and Sadaf Zaidi\*

Sciences, Aligarh Muslim University, Aligarh, India

provided the original work is properly cited.

\*Address all correspondence to: sadaf63in@yahoo.com

Department of Post Harvest Engineering and Technology, Faculty of Agricultural

© 2020 The Author(s). Licensee IntechOpen. This chapter is 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,

*Potential Use of Agro/Food Wastes as Biosorbents in the Removal of Heavy Metals*

the effluents that are generated from various industrial activities. This method has proven itself to be efficient and environmental friendly. It solves the problems of the health and environmental hazards of heavy metals in our ecosystem and the utilization of huge quantities of agro/food waste. The use of agricultural wastes as bioadsorbent is recommended because of their sustainability, easy availability, low cost, and high affinity towards the removal of heavy metals. Numerous studies have recommended the use of several agro and food wastes such as wheat bran, coconut shell, rice bran, wheat husk, and rice husk, etc. either in their natural form or after some modification for the removal of chromium, cadmium, cobalt, nickel, lead, etc. In literature very few details are available regarding the modification and regeneration of biosorbents, about the pore size distribution of adsorbent, recovery of metal ions, and molecular size of metal ions. Thus, a lot of work is still required to be done in this direction in the coming days for the effective transformation of

*DOI: http://dx.doi.org/10.5772/intechopen.94175*

agro/food waste into the biosorbents.

#### *Potential Use of Agro/Food Wastes as Biosorbents in the Removal of Heavy Metals DOI: http://dx.doi.org/10.5772/intechopen.94175*

the effluents that are generated from various industrial activities. This method has proven itself to be efficient and environmental friendly. It solves the problems of the health and environmental hazards of heavy metals in our ecosystem and the utilization of huge quantities of agro/food waste. The use of agricultural wastes as bioadsorbent is recommended because of their sustainability, easy availability, low cost, and high affinity towards the removal of heavy metals. Numerous studies have recommended the use of several agro and food wastes such as wheat bran, coconut shell, rice bran, wheat husk, and rice husk, etc. either in their natural form or after some modification for the removal of chromium, cadmium, cobalt, nickel, lead, etc. In literature very few details are available regarding the modification and regeneration of biosorbents, about the pore size distribution of adsorbent, recovery of metal ions, and molecular size of metal ions. Thus, a lot of work is still required to be done in this direction in the coming days for the effective transformation of agro/food waste into the biosorbents.
