Selective Adsorption of Cr (VI) in Industrial Waste Water Using Green Sorbent Materials

Abstract

. Recently, concern about chromium as an environmental pollutant has been escalating due to its build up to toxic levels in the environment such as surface water, groundwater, soil and air as a result of various industrial activities. Chromium often occurs in the trivalent (III, chromic) or hexavalent (VI, chromate) states under natural environmental conditions. The removal of Cr (VI) which is known toxic and carcinogenic from industrial wastewater by different green sorbent materials was investigated. Wood bark, coir and peat were used. The different chromium concentration, contact time and adsorption–desorption properties on the selectivity of the removal process was investigated. The Langmuir isotherm was applicable to the adsorption process. In batch method wood bark was the best sorbent among the percentage of chromium desorbed about 9 % at 50 mg/l initial Cr (VI) concentration. The flow through systems of wood bark was applied to found residence times. Wood bark completely retained chromium from solutions with sufficient amount and longer contact times. The data obtained is applicable to refer to a large scale of purifications systems.