To develop an efficient and cost-effective adsorbent for phosphate removal from water bodies, this study utilized natural red clay (RC) as a carrier. The modified red clay (MRC) was prepared through three methods: acid modification, high-temperature calcination, and metal loading. The preparation conditions were optimized, and the adsorption effects on phosphate were compared across these different modifications. The key findings are as follows: (1) The adsorption capacity of MRC for phosphate, based on the modification method, is ranked as 700 °C calcined modified red clay (MRC-700) >
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