Removal of Lead and Arsenic from Water/Wastewater by Rice Husk and Optimization by Box–Behnken

The presence of large amounts of contaminants such as organic compounds and heavy metals in aquatic systems, is a major problem which has created many concerns for the health of human societies. adsorption and the use of Affordable adsorbents is attracted much attention. The purpose of this study is removal of lead and arsenic from aqueous solutions by rice husk and optimization the method by using the response surface method (RSM) based on Box-Behnken Desine. Rice husk and polytetrafluoroethylene carbonized at 600-900 °C in nitrogen, and the silica is removed in situ. Morphological and structural properties of absorbent surface were determined by FESEM and XRD and Pb and As concentrations were measured by ICPE. the effect of independent variables including pH, contact time, adsorbent amount and initial concentration of heavy metal on removal of Pb and As by carbonized rice husk was investigated. analysis of variance was performed to data analysis and finding the removal equation. The results showed that efficiency of removal increased with increasing independent variables in wide range of Pb, As concentrations, but removal of Pb was done at lower times. In optimal pH, the efficiency is high, even at low concentrations of absorbent. Also, based on the findings, it can be concluded that the experimental design method is an effective method for reducing costs and experiments, and examining the interactions of variables can help us to better understand the effects of independent variables on dependent variables. The Maximum and minimum percentages of removal is 97%, 30% in Pb and 85%, 30% in As. as a result carbonized rice husk can be used for removal of Pb and As from aqueous solutions, and the response surface method Can be effective to optimize removal