Coagulation is a simple and cost-effective water treatment method that does not work well in removing multiple cationic and anionic heavy metals simultaneously from drinking water. Titanium potassium oxalate (K₂TiO(C₂O₄)₂), a fur tanning reagent, was found to be able to efficiently remove arsenite (As(III)), arsenate (As(V)), and Cd simultaneously. A dose of 120 µmol/L K₂TiO(C₂O₄)₂ could remove more than 90% of As and Cd to meet the drinking water standards when their initial concentrations were 10 times their maximum concentration limits, whereas traditional coagulants, such as Fe₂(SO₄)₃ and Al₂(SO₄)₃, failed to meet the drinking water standards. Additionally, K₂TiO(C₂O₄)₂ coagulation consumes natural water hardness (Ca²⁺/Mg²⁺) to produce softer water and releases healthy K⁺ as a by-product. The mechanism study indicated that K₂TiO(C₂O₄)₂ reacted with natural calcium ions in drinking water to form calcium oxalate, while residual titanium was hydrolyzed with water to form hydrous titanium oxide. Arsenic was removed primarily via complexation with hydrous titanium oxide, while Cd was removed via the combined effect of adsorption by hydrous titanium oxide and mixed-crystal formation by calcium oxalate. This study provides an efficient coagulant for removing multiple heavy metals simultaneously, which can be applied in water treatment to provide safe and healthy drinking water.

混凝是一种简单且经济高效的水处理方法，但不能很好地同时去除饮用水中的多种阳离子和阴离子重金属。草酸钛钾 (K ₂ TiO(C ₂ O ₄ ) ₂ ) 是一种毛皮鞣剂，被发现能够同时有效去除亚砷酸盐 (As(III))、砷酸盐 (As(V)) 和 Cd。120 µmol/LK ₂ TiO(C ₂ O ₄ ) 2 的初始浓度为最大浓度限值的 10 倍时，120 µmol/LK 2 TiO(C 2 O 4 ) ₂可去除超过 90% 的 As 和 Cd 以满足饮用水标准，而传统混凝剂，如Fe ₂ (SO ₄) ₃和Al ₂ (SO ₄ ) ₃，未能达到饮用水标准。此外，K ₂ TiO(C ₂ O ₄ ) ₂凝结消耗天然水硬度 (Ca ²⁺ /Mg ²⁺ ) 以产生更软的水并释放健康的 K ⁺作为副产品。机理研究表明K ₂ TiO(C ₂ O ₄ ) ₂与饮用水中的天然钙离子反应生成草酸钙，而残留的钛遇水水解生成水合氧化钛。砷主要通过与含水二氧化钛络合去除，而镉通过含水二氧化钛吸附和草酸钙形成混晶的联合作用去除。本研究提供了一种同时去除多种重金属的高效混凝剂，可应用于水处理，提供安全健康的饮用水。