Selected Sorption Materials for Removal of Heavy Metals from Water

Increased pollution of water resources leads to deterioration of surface water and ground water quality and it initiates application of various methods for water treatment. Passing the Decree of the Ministry of Health of the Slovak Republic No. 247/20174 on requirements for drinking water and monitoring of drinking water quality have determined the limit of heavy metal concentrations in drinking water. Based on this fact some water resources in Slovakia became unsuitable for further use and they require appropriate treatment. The present research related to removal of heavy metals is focused on introduction of natural materials as well as industrial and agricultural waste that can be used as cost-effective sorption materials. Arsenic and antimony are present in the aquatic environment as result of rock weathering reactions, biological activity, geochemical reactions, volcanic emissions, mining operations and anthropogenic activities. The objective of this work was to verify the sorption properties of granular filter materials READ-As (hydrous cerium dioxide adsorbent) in removal of heavy metals from water. This material was developed in Japan for removal of arsenic from water. One part of experiments was carried out in ground water source Dubrava, where a high concentration of antimony in water is caused from mining activities as well as from rain falling on antimony-rich waste rock piles and a sludge-settling pond has led to higher concentrations of antimony in the relevant water resources. At the other part of article there are presented results with the same material READ-As for removal of arsenic from ground water source in Jasenie. The values of the bed volume and the adsorption capacity for this sorption material when reaching the limit concentration of antimony and arsenic were determined. READ-As material has shown to be more efficient in antimony removal from water in Dubrava locality than GEH, for average antimony concentrations of antimony in a raw water 27.73 mu g/L, filtration rate 5.58 m/h reached the antimony concentration of 5 mu g/L in the outflow from the adsorption column of high level 48 cm, V/Vo (bed volume) 3967 and adsorption capacity of a value 128.4 mu g/g. Limit concentration of antimony 5 mu g/L was exceeded after 336 hours of operation of the model equipment. Lower efficiency of the GEH material in Sb removal from the water was observed in consideration with currently published results. By pilot plant tests in Jasenie locality was determined adsorption capacity 354 mu g/g and ration V/V0 (bed volume) 5130 mu g/g for water with arsenic content of 55-60 mu g/L and filtration rate 5.35 m/h, two steps filtration with READAs material. These values were determined when the limit concentration of arsenic in water outflowing the columns (10 mu g/L) was reached. Mentioned values are significantly higher than it was in a case of antimony.