Development of pellet-type adsorbent based on water treatment residual

摘要

To obtain a low-cost adsorbent with a regular shape for the better application in water pollution control practice, drinking water treatment residual (DWTR) was modified by adding different proportions of kaolin clay, and the pellet-type adsorbents were then made under the thermal treatment approach. Response surface methodology (RSM) was applied to optimize the production process and analyze the effects of firing time, firing temperature and DWTR proportion on phosphorus (P) adsorption capacity and mass loss ratio, which was chosen as the parameter of strength of the resultant DWTR-clay pellets. The results showed that an increasing temperature contributes to greater strength but leads to smaller P adsorption capacity, while kaolin clay addition results in an improvement of strength but a decrease of P adsorption capacity. The best P adsorption of 10.2 mg P/g pellet was obtained under the conditions of making the pellet with 40% clay addition while heating at 650 degrees C for 60 min. The strength of DWTR pellet could be increased by thermal treatment with kaolin clay. This study can help the large-scale application of DWTR as a low-cost adsorbent in many kinds of water and environmental engineering practices, such as using DWTR as a substrate in the artificial floating island.