Effect of Different Exogeneous Compounds on Biosorption of Endosulfan

Problem statement: Organochlorine pesticide endosulfan is widely used as a replacement for DDT and dieldrin in many parts of the world. Presence of residual pesticides in the water, air and soil environment was confirmed since 1960s. Such Persistent Organic Pollutants (POPs) are of concern because of their long-term subtle effects on hormones, the immune system and reproduction. Therefore, it becomes imperative to develop indigenous technologies for remediation of endosulfan in contaminated water and contaminated sites. Comparison to conventional pesticide removal techniques, biosorption is a kind of promising technique that can accumulate organic and inorganic matter from aqueous solution. The presence of exogenous compounds might shows significant influence on the performance of biosorption/adsorption process and it may become necessary to perform certain pretreatment to diminish their impacts. Approach: The effects of pH, size of biosorbent, ionic strength, presence of inorganic substances such as calcium ion, magnesium ions, chloride ions, fertilizers and presence of organic substances such as dissolved organic matter, surfactant and other pesticides on biosorption of endosulfan onto biosorbent prepared from fungal culture Aspergillus Nidulans (ANS) was investigated in this study. Results: The removal efficiency was more for fine biosorbent particles. Maximum removal of endosulfan was observed at pH 6.4 and no significant effect was found with variation of ionic strength. The presence of chloride, magnesium and calcium ions and surfactant did not affect the removal significantly. The presence of fertilizers such as Urea and Single Super Phosphate did not affect the removal efficiency significantly. Background dissolved organic matter (as humic and polyacrylic acids) was found affecting the removal efficiency of endosulfan significantly. Both the co-sorbents viz. atrazine and monocrotophos almost equally hindered the sorption capacity of ANS biosorbent for the biosorption of endosulfan. Conclusion: Exogenous parameters played an important role in removal efficiency of endosulfan during the biosorption process by ANS biosorbent. There is a need for pretreatment in order to design integrated endosulfan biosorption treatment with concern of the substances present along with endosulfan in water environment.