Experimental research on the heavy metal removal from contaminated water by synthetic sobents

Abstract

Heavy metals are toxic and harmful even at low concentrations. Sorption and ion exchange are the most often used processes for heavy metal removal. However, the need exists for low cost, effective and regenerable sorbent materials, which are capable of removing metal ions from polluted water. Natural or synthetic sorbents due to their high sorption capacity, selectivity, the properties of cation exchangeability, a low price and affordability are used to remove heavy metals from polluted water. The experimental research on the sorption of heavy metals (Mn, Pb and Cu) from contaminated water by synthetic sorbents (silica gel KCM and cation-exchange resin KU 2-8) was carried out. pH impact on the cation-exchange resin and silica gel KMC sorption capacity was estimated, the remaining concentrations of heavy metals in solution were measured and exchange sorption capacity of sorbents was calculated during the research in order to find out optimal conditions of heavy metal removal from contaminated water. The results of research showed that cation-exchange resin KU 2-8 and silica gel KMC capable to sorb heavy metals from contaminated water and cation-exchange resin KU 2-8 characterized by greater sorption capacity in comparison with silica gel KMC. Both sorbents are capable to sorb lead in the best way. Sorption of copper is worse and manganese sorption is the worst. It is likely that bigger atomic radius of heavy metal more suit size of sorbent’s pores and the more they are nearer the bigger sorption capacity of the sorbent is. The results of the research showed that the maximum sorption capacity of cation-exchange resin KU 2-8 is reached at pH between 3 and 4 and it is: ESCPb = 0,505 mg/g; ESCCu = 0,475 mg/g; ESCMn = 0,472 mg/g. The highest sorption capacity of silica gel KMC is reachable at: pH = 8 – for lead and copper, pH = 7–8 – for manganese. Probably at very acidic environment (pH≈1) sorbents almost don’t sorb heavy metals from solution.