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International Conference on

Recent Trends in Environmental Sustainability

ESCON22/ETERM/22
Assessment of adsorption behavior of Cd for various sources of biochar using different
adsorption isotherm models

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Jannat Khatoon , Muhammad Ashar Ayub , Muhammad Zia-ur-Rehman , Husnain Zia ,
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Muhammad Umair , Muhammad Usman
1 Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad
Correspondence: ziasindhu1399@gmail.com
Abstract
Cadmium being a non-essential and toxic metal is a very potent toxin for the environment being
released through natural and anthropogenic activities. Its toxicity in plants is observed even in
very low concentrations which is mainly due to the metabolic disturbance in the plant. Upon
accumulation in the plant’s body, Cd can make its way to the human food chain whereupon
accumulation in humans lead to various diseases. Wastewater is a big source of Cd input in
agriculture, but proper management of wastewater can decrease the threat of Cd toxicity
remarkably in the agro-ecosystem. The use of various amendments for the physical absorption
of Cd from water is a well-tested approach and biochar is one of the most important
amendments in this regard. In this study, biochar from different feedstocks including Poultry
Manure (PMB), Rice Husk (RHB), Rice Straw (RSB), Cotton Straw (CSB), Wheat Straw
(WSB), Sugarcane Straw (SB), and Vegetable Waste (VB) were used for evaluating their
adsorption capability. Various amounts of these biochars (0.1, 0.2, 0.3 g) were tested for Cd
removal from solutions (20 ml) of 0, 10, 20, 40, 60, 80, 100, 120, and 140 ppm Cd. Coefficient
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of determination (R ) of three adsorption isotherms (Temkin Isotherm Model, Langmuir
Isotherm Model and Freundlich Isotherm model) were used to interpret the behavior of
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cadmium adsorption. Results revealed that R values of the Langmuir model were 0.9967,
0.9978, 0.7652, 0.4843, 0.995, 0.9816 and 0.9474 for PMB, RHB, RSB, CSB, WSB, SB and
VB, respectively at 0.1 g biochar application. Coefficient of determination for 0.2 g biochar
application were 0.9952, 0.9948, 0.7147, 0.4654, 0.9961, 0.9889 and 0.9439 for PMB, RHB,
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RSB, CSB, WSB, SB and VB, respectively. Similarly, for 0.3 g biochar R values were 0.9862,
0.9856, 0.6896, 0.4576, 0.9881, 0.9847 and 0.9334 for PMB, RHB, RSB, CSB, WSB, SB and
VB, respectively. Coefficient of determination for Freundlich Isotherm model for 0.1 g biochar
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were 0.8409, 0.8503, 0.5734, 0.5472, 0.7947, 0.6747, 0.6251; for 0.2 g biochar R values were
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0.9568, 0.9578, 0.7536, 0.7305, 0.9312, 0.8437, 0.8008; and for 0.3 g biochar R values were
0.9769, 0.9773, 0.811, 0.7922, 0.9586, 0.8872, 0.8507 for all the seven biochar sources PMB,
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RHB, RSB, CSB, WSB, SB and VB, respectively. Values of R for Temkin model for 0.1 g
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biochar were 0.8372, 0.8787, 0.631, 0.6164, 0.7961, 0.7047, 0.6666; for 0.2 g R values were
0.9761, 0.9946, 0.9224, 0.9147, 0.9754, 0.9563 0.9399, and for 0.3 g values were 0.9632,
0.9743, 0.9674, 0.963, 0.9757, 0.9837 and 0.9767 for PMB, RHB, RSB, CSB, WSB, SB and
VB, respectively. Among all tested biochar sources, the rice husk biochar was found to be most
efficient due to its 83.16% of adsorption capacity for removal of Cd from water.

Keywords: Rice husk biochar; Pb pollution; Wastewater; Langmuir model

Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus

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