Among the different factors that influence the liquid-solid adsorption technique, equilibrium time is one of the most relevant and requires a large number of experiments over a long period of time for its determination. This work evaluates the Southwell Plot as a further tool that can contribute to determining the equilibrium time in adsorption processes. It can also optimize the operating conditions in a batch system for the removal of phosphate in adsorbents produced from domestic sewage sludge and clam shell residue. Sewage sludge and clam shell residues were ground, sieved and sintered at 700 °C for 1 h. The material was characterized by thermal analyses (TG/DTG), chemical analysis (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and adsorption studies. The kinetic studies were investigated by varying the initial concentration of the phosphate solution and mass of the adsorbent. The equilibrium time was determined by applying the Southwell Plot method to the kinetic data and the results showed some fluctuations as a function of the adsorbent mass. At 0.30 g of the adsorbent in 30 mL of the phosphate solution, regardless of the initial phosphate concentration, the equilibrium time determined by the Southwell Plot was 4 h. The maximum phosphate adsorption capacity in this condition, determined by the Langmuir equation, was 49.45 mg g⁻¹.

在影响液固吸附技术的不同因素中，平衡时间是最相关的因素之一，需要在很长一段时间内进行大量实验才能确定。这项工作将 Southwell Plot 评估为一种有助于确定吸附过程平衡时间的进一步工具。它还可以优化批量系统中的操作条件，用于去除生活污水污泥产生的吸附剂中的磷酸盐和蛤壳渣。将污水污泥和蛤壳残渣磨碎、筛分并在 700 °C 下烧结 1 小时。该材料通过热分析 (TG/DTG)、化学分析 (EDX)、X 射线衍射 (XRD)、傅里叶变换红外光谱 (FTIR) 和吸附研究进行表征。通过改变磷酸盐溶液的初始浓度和吸附剂的质量来研究动力学研究。平衡时间是通过将 Southwell Plot 方法应用于动力学数据来确定的，结果显示一些波动是吸附剂质量的函数。在 30 mL 磷酸盐溶液中含有 0.30 g 吸附剂时，无论初始磷酸盐浓度如何，Southwell Plot 确定的平衡时间为 4 h。该条件下的最大磷酸盐吸附能力，^-1。