Removal of Chromium by Biosorption Method (Chitosan)

Abstract

Discharge of metal containing effluents into water has been a cause of major concern. Traditional treatment methods are proving to be ineffective and expensive. Chitosan was studied as a potential biosorbent due to its positive charge and relatively low cost. The study involves evaluating the metal binding performance of chitosan in a Polymer Enhanced Diafiltration (PEDF) system which uses an ultra filtration membrane to retain the chitosan which, in turn, binds the metal, thereby preventing passage into the permeate stream. Conditions for binding such as pH, concentration of polymer and chromium were studied. Optimal performance was obtained when the system was operated at pH values lower than the pKa of chitosan i.e. 6.3. Using 6 g/L chitosan at pH 4.0, chromium concentration was reduced to less than 1mg/L from a feed concentration of 20 mg/L. Equilibrium dialysis experiments were done to study the kinetics of binding and the uptake of metal per gram of polymer. Rheological measurements demonstrated that in the presence of 1-100 mM chromate, chitosan was found to be slightly shear thickening at low concentrations such as 4 g/L and 6 g/L whereas it was slightly shear thinning at higher concentrations like 12 g/L and 20 g/L This suggests that neutralization of chromium anions is due to the interaction of multiple chitosan molecules. This result is consistent with the relatively stiff nature of the polysaccharide. Overall, this study suggests that some modification of the native polymer would be required to improve uptake and make it an industrially workable process.

Studies on Waste Plastics to Extract Oil By Pyrolysis Method and Its Applications

“…Amount of yield consumption by using different plastics without catalyst: It is observed that when a plastic material like polyethylene is used as solo material without the support of a catalyst, the yield is 74 % whereas in polystyrene material [13], the yield is about 82 %. When combination of plastics is used, the yield is about 66 % with less amount of residue [14] (Fig.…”

Removal of some Heavy Metals from Industrial Wastewater and Gray Water by using some Natural and Organic Materials

“…[17], showed increased pollution with heavy metals, especially Pb, in soil of battery factories in Al-Waziriyah-Baghdad has exceeded internationally permitted limit. [18], showed that irrigation with water contaminated with heavy metals leads to accumulation of these elements in soil and makes it polluted.Process of draining contaminated water is difficult and relatively expensive, and there are many traditional treatment methods that are usually ineffective and expensive [19], therefore, many new technologies that are considered natural bio-alternatives have been used for easy cleaning elements from polluted water by adsorption method using biomass adsorbent. Use of low-cost adsorbents for treatment of contaminated water is currently recommended because adsorbents are usually available in large quantities and are therefore cost-effective and inexpensive [20].…”

Minimization of Phenol by Natural Occurrence Adsorbent

“…Natural occurrence materials are used as adsorbent for reduction. The effect of pH, dosing, contact time, isotherm has been also studied [25][26][27][28][29][30][31][32].…”