Evaluation of omphacite and iron-coated omphacite as a water filtration medium

In this study, omphacite medium were modified by roasting at high temperature. The optimal preparation conditions were as follows: the pH value was 1, concentration of FeCl3 was 2 mol/L, roasting temperature was 450 °C and roasting time was 2 h. Specific surface area, scanning electron microscopy, and EDS analysis were used to compare the unmodified and modified omphacite, and a dynamic filtration experiment was performed to treat the slightly polluted water. The analysis of the characterization results revealed that the surface structure of the modified omphacite filter medium changed greatly. Its surface was rough and potholes increased, and the specific surface area and adsorption capacity were significantly increased. Results of the dynamic filtration experiment revealed that the average removal efficiencies of organic matter, TOC, and turbidity by quartz sand were 21.17%, 2.2%, and 94.5%. The average removal efficiencies of organic matter, TOC, and turbidity by unmodified omphacite were 23.46%, 26.7%, and 95.2%. The average removal efficiencies of organic matter, TOC, and turbidity by modified omphacite were 50.35%, 45.5%, and 96.3%. On the whole, the filtration performance of the modified omphacite filter column was the best among the three filter columns, and the recovery of the backwashing performance was also better.