Biosorption of methylene blue in aqueous solution using structurally modified rice husk and its notable compatibility, biosafety potential – A sustainable approach towards the management of hazardous dyes

Abstract

In vitro batch system was adopted to determine the dye removal and uptake efficacy by providing various optimum condition which includes initial dye concentration, adsorbent dosage, contact time, pH, temperature. Surface modified rice husk was screened for biocompatibility or biosafety potential using phytotoxicity assessment, brine shrimp toxicity, hemocompatibility and mutagenicity screening. Optimum condition for the dye adsorption includes 1750 mg of adsorbent dosage, 25 mg/L of initial dye concentration, 100 min of contact time, 45 oC temperature, 7.5 pH Adsorbed dye in aqueous solution thus obtained under optimum condition was not shown any phytotoxic effect on the seedling index of Vigna mungo, Vigna radiata and Brassica niger, enzymatic anti-oxidants level, biochemical composition like total protein, total carbohydrate, total chlorophyll, qualitative protein expression pattern. No impact on the hatching, survival rate, morphology, anti-oxidants profile of brine shrimp -Artemia salina that exposed to surface modified rice husk treated dye in aqueous solution revealed best biocompatibility. No sign of hemolysis on the peripheral blood that treated with adsorbed dye in aqueous solution also confirmed the biocompatibility. No induction of cytotoxicity, and apoptosis in the RAW cell line that exposed to treated dye in aqueous solution was also confirmed the best biocompatibility. Mutagenicity screening with bacterial strain Salmonella typhimurium His- bacterial detection system adopting Ames test showed absence of revertant bacterial colonies indicated the best biosafety or biocompatibility. The present study suggests the possible utilization of rice husk treated methylene blue in aqueous solution for agriculture or irrigation purpose with high biocompatibility and biosafety.