Biosorption of copper from waste waters: A review

A comprehensive literature review has been carried out on the sorption of c opper ions onto various biosorbents. Extensive research has been carried ou t using peat as a sorbent and the sorption capacity of copper on different peats varies by a factor of over fifty. Furthermore, this paper identifies that copper sorption capacities have been reported for over thirty other di fferent biosorbents. The paper reviews the capacities of the various biosor bents for copper and discusses the range of kinetic mechanisms used by diff erent researches to correlate kinetic experimental data. The suitability of the various kinetic models for the sorption of copper from wastewaters ont o different biosorbents is discussed. The review identifies several deficiencies in the literature. Many of the s tudies on equilibrium isotherms only apply one method of analysis. Research ers fail to test experimental equilibrium date using several models and do not determine the best fit model by error analysis or by postulating a sorp tion mechanism. The same criticism is valid for kinetic studies. The applic ation of more than one kinetic model is extremely rare. Another major probl em arises in the characterisation of adsorbent materials, since very little information is provided on surface area, pore size distribution, surface a ctivity, particle size, hardness or attrition rates and influence of pH. Th ese are key factors in developing and designing wastewater treatment system s.