Removal of airborne hexavalent chromium using alginate as a biosorbent

ABSTRACT

Airborne hexavalent chromium has been classified as a human respiratory carcinogen and long term exposure has been known to cause ulceration and perforation of the nasal septum, bronchitis, asthma, and liver and kidney damage. Chromium electroplating plants are the major sources of atmospheric chromium and packed-bed scrubbers are the common control devices used to reduce emission of chromic acid mist from electroplating bathes. The feasibility of a new method to remove this pollutant using alginate beads as a biomass derivative was investigated by one factor at a time approach and Taguchi experimental design. Polluted air with different chromium mist concentrations [10-5000 micro g/m3] was contacted to alginate beads [3.3-20 g/L], floating in distilled water with adjusted pH [3-7], using an impinger at different temperatures [20 and 35°C], and various velocities [1.2 and 2.4 m/s]. Although there were no statistical significant differences between factor levels, the higher ions removal efficiencies were achieved at lower levels of air velocities, pollution concentrations, higher levels of pHs, temperatures, and sorbent concentrations