Chemical pre-treatments of oil palm frond for improvement in the removal of zn and cu from wastewater by sorption process

摘要

As a result of industrialization, Environmental pollution is becoming more and more serious. Heavy metals are often present industrial wastewaters and need to be removed before discharge. Adsorption is a commonly used method for heavy metal removal from aqueous solutions. Despite of the good efficiencies for heavy metal removal still the process can be improved by chemical or physical improvement of the sorbent material. The effects of different pre-treatments on oil palm frond (OPF) with the objectives of improving the sorption of Zn and Cu have been investigated. Acid, base, steam and reactive dye treatment were investigated for improvement in the sorption process. Base treatment resulted in the highest improvement in the heavy metals sorption capacity of the sorbent (64%). In this study the sorption process was fitted with the Langmuir and Freundlich isotherm lines which resulted in high fitting with R2= 0.99. The response surface methodology was employed in order to optimize the conditions of the base pre-treatment of OPF. It resulted in two quadratic models, one for Zn and one For Cu, demonstrating the less effect of time of treatment against the high effect of the base solution concentration. The conditions for the optimized process were soaking the sorbent in a 1.0 M solution of NaOH for 45 min under normal room temperature of 25 °C.