The use of synthesized zeolites from power plant rice husk ash obtained from Thailand as adsorbent for cadmium contamination removal from zinc mining

The people from the 12 villages near the zinc mining in Mae Sot District, Tak Province, and Northwest of Thailand, were suffering contamination with cadmium (Cd2+). It was released into the main source of water supply, Mae Taw River, which also be used for agriculture. This represents a serious problem that should be addressed accordingly. This study aims to investigate the synthesized zeolite from agriculture waste by-product in Thailand such as; rice husk ash (RHA) with white part is containing high silica content which can be used as a potential zeolites precursor and used to solve the problem by removing cadmium in aqueous solution via batch experiments. The removal of Cd2+ in the concentration range of 50-500 mg/L. The maximum removal capacity of synthesized zeolite Na−A and Na−X for Cd2+ were found to be 736.38 and 684.46 mg/g, respectively. The result was compared to synthetic zeolite 3A commercial shown that synthesized zeolites from RHA have high removal capacity close to commercial one of 753.58 mg/g using 0.3 g/L dosage of zeolite and consistent with an endothermic reaction, an increase in the temperature (20-40 °C) resulted in increasing cadmium adsorption rate. Therefore, the synthesized zeolites from RHA have high potential to remove cadmium contamination in water.