Reaction of fluoride with waste oyster shell was studied. To enhance the stability and adsorption capacity, oyster shell was coated with Al(OH)₃ and the adsorption behaviors were compared with the uncoated one. When at low fluoride concentration (<30 mg/L), fluoride removal efficiency decreased with increasing pH, and the adsorption could be modeled by Langmuir isotherm. At high fluoride concentration (>100 mg/L), linear adsorption isotherm fitted better, in which the adsorption capacity of fluoride increased linearly with increasing equilibrium fluoride concentration. The coated oyster shell showed higher adsorption capacity and wider workable pH range. From XPS analysis, the presence of CaF₂ was confirmed by the peak at 684.7 eV when fluoride concentration increased. It was noted that magnesium content of waste oyster shell reacted with fluoride to form significant fractions of MgF₂ whose corresponding peak was detected at 685.6–685.8 eV. For coated oyster shell, fluoride reacted with Ca, Mg, and Al. The reaction mechanism was mainly adsorption at low initial concentration, and precipitation-dominated at higher concentration.

研究了氟化物与废牡蛎壳的反应。为了提高稳定性和吸附能力，牡蛎壳涂有Al（OH）_3，并将其吸附行为与未涂覆的牡蛎壳进行了比较。在低氟化物浓度（<30 mg / L）下，除氟效率随pH值的增加而降低，并且可以用Langmuir等温线模拟吸附。在高氟化物浓度（> 100 mg / L）下，线性吸附等温线拟合得更好，其中氟化物的吸附容量随平衡氟化物浓度的增加而线性增加。涂覆的牡蛎壳显示出更高的吸附能力和更宽泛的pH范围。根据XPS分析，CaF ₂的存在当氟化物浓度增加时，在684.7 eV处的峰证实了这一点。值得注意的是，牡蛎废壳中的镁含量与氟化物反应，形成了大部分MgF _2，其相应的峰在685.6–685.8 eV处检测到。对于带涂层的牡蛎壳，氟化物会与Ca，Mg和Al反应。反应机理主要是低浓度下的吸附，高浓度下的沉淀为主。