Biosorption of Cr [VI] by resting cells of Fusarium solani

Chromium is one of the toxic heavy metals which exists in nature as stable hexavalent and trivalent forms. The hexavalent form of chromium is more toxic than trivalent chromium as it persists indefinitely in the environment complicating its remediation. The conventional physical and chemical treatment techniques used for the removal of Cr[VI] are expensive and highly energy intensive, moreover they produce harmful by-products, ultimate disposal of which again causes secondary pollution. Removal of Cr[VI] from aqueous solution using biological sources as biosorbent has assumed advantageous over the existing conventional physico-chemical techniques for the treatment of metal contaminated wastes. The present batch biosorption study was undertaken with an aim to examine the Cr [VI] removal potential of the resting cells of Fusarium solani [isolated from soil] from aqueous solution. The specific Cr [VI] removal decreased with increase in pH and increased with increase in initial Cr[VI] concentration, up to 500 mg/L. The specific Cr[VI] removal remained almost constant by increasing biomass concentration from 2.4 to 5.2 g/L. The studies also carried out by using the resting cells obtained from various stages of growth and the maximum specific Cr[VI] removal [60 mg/g] was achieved at 500 mg/L initial Cr[VI] concentration and by using cells [36 h old]. The Langmuir adsorption isotherm constants, Q[o] and b were observed to be 57.1 mg/L and 0.06 I 1/mg, respectively

Chromium removal using various biosorbents

Pollution of water due to presence of certain heavy metal ions is a severe socio-environmental problem caused by the discharge of industrial wastewater. In view of their toxicity, non-biodegradebility and persistent nature, their removal becomes an absolute necessary. Chromium is one of the major pollutants in the environment and is frequently present in wastewaters from various industrial units. Several conventional physical and chemical treatment techniques may be used for the removal of chromium. However, such processes are not only expensive and highly energy intensive, but also lead to production of harmful by-products and end-products, the ultimate disposal of which again causes secondary pollution. Hence, the potential application of microorganisms as biosorbent for the removal of chromium has been recognized as an alternative to the existing conventional physico-chemical methods. The aim of the present study is to review the removal of chromium from aqueous solution using various materials of agricultural and biological origin, which have been studied as potential chromium biosorbent [plant leaves, saw dust, sugar cane bagassa, sugar beet pulp, maize cob and rice hulls]. Also reported cases on chromium removal from aqueous solution by using fungal, algal and bacterial biomass under the growing, resting and dead conditions in batch as well as in continuous bioreactors are reviewed

Biosorption of CR [VI] by resting cells of Aspergillus Sp.

Biosorption of Cr[VI] from aqueous solution was studied in a batch bioreactor using the resting cells of filamentous fungal biomass [Aspergillus sp.] isolated from industrial wastewaters. The specific Cr[VI] removal [mg/g of dried biomass] decreased with increase in pH and increased with increase in initial Cr[VI] concentration, upto 500 mg/L. By increasing biomass concentration from 2.4 to 5.2 g/L, the specific metal removal remained almost constant. The studies carried out by using the resting cells from various stages of growth indicated maximum Cr[VI] removal of 34.8 mg/g using the biomass from the beginning of the stationary phase. The adsorption equilibrium constants Q° [42.9 mg/g] and b [0.0091/mg] were obtained from the Langmuir adsorption isotherm model