Waste oyster shells were used to remove phosphate and the effects of thermal pretreatment were studied. Thermal pretreatment under different conditions (400 °C for 0.5 h, 400 °C for 2 h, and 700 °C for 2 h) shifted the isoelectric point (pH_IEP) of oyster shells to more alkaline range, while surface area decreased from 3.47 to 0.52 m²/g when pretreated at 700 °C for 2 h. Phosphate adsorption was enhanced when using pretreated oyster shells. Adsorption fitted well with Langmuir isotherm model. Both the maximum monolayer coverage (Q₀) and the adsorption constant (b) increased when using oyster shells preheated at 400 °C. The values of Q₀ and b increased significantly to 5.332 mg/g and 0.728 L/mg, respectively, at pH 10.59 when using oyster shells preheated at 700 °C for 2 h, which could be attributed to the formation of calcium oxide (CaO) as evidenced by analysis of X-ray photoelectron spectroscopy (XPS). Both adsorption and precipitation processes were involved in the reactions as supported by analysis of loaded oyster shells by XPS, and hydroxyapatite (Ca₅(PO₄)₃(OH)) was formed on surfaces of oyster shells.

使用废牡蛎壳去除磷酸盐，并研究了热预处理的效果。在不同条件下（400°C持续0.5 h，400°C持续2 h和700°C持续2 h）进行热预处理将牡蛎壳的等电点（pH _IEP）移至更大的碱性范围，而表面积从3.47减小于700°C预处理2 h时达到0.52 m ² / g。使用预处理过的牡蛎壳时，磷酸盐的吸附作用增强。吸附非常适合Langmuir等温模型。当使用在400°C下预热的牡蛎壳时，最大单层覆盖率（Q ₀）和吸附常数（b）均增加。Q ₀和b的值当使用在700°C下预热2小时的牡蛎壳时，在pH 10.59时分别显着增加至5.332 mg / g和0.728 L / mg，这可能是由于X的分析所证明的形成了氧化钙（CaO）射线光电子能谱（XPS）。通过XPS分析负载的牡蛎壳，吸附和沉淀过程均参与了反应，并且在牡蛎壳表面形成了羟基磷灰石（Ca ₅（PO ₄）₃（OH））。