Investigation of effective factors in adsorption of Cu(II) and Pb(II) in wastewater refinery on bentonite by using box behnken design

Eliminating metal ions from wastewater is an important issue that has been researched extensively (1). Methods such as precipitation, membrane separation, ion exchange, solvent extraction, and electrochemical reduction can be used. However, these methods are often ineffective and costly. For instance, when the contaminations are present in trace amounts, precipitation is not practical and also a large amount of sludge is produced. In contrast to most of these methods, adsorption has been proved to be one of the most simple, feasible, and efficient method for elimination of heavy metals from contaminated water. Among the different adsorbents zeolites are effective and inexpensive candidates but, many factors can affect the efficiency of them (2). The Box–Behnken design (BBD), a kind of RSM, is a second-order experimental design method that received widespread application in optimization of experimental conditions (3).In this study, the elimination of Pb2+ and Cu2+ using bentonite sorbent was reported. The significant factors including pH, time, and sorbent amount were optimized and, also, the interactions were investigated by BBD. The samples and real samples (sea water and wastewater) were analyzed by atomic absorption spectrometry (AAS). The figures of merit under optimized removal conditions were reported.