Na2co3

Mt used in this study was obtained from Nanhai, Guangdong province, China. Its cation exchange capacity (CEC) and specific surface area is 0.78 meq·g⁻¹ and 71 m²·g⁻¹, respectively. The chemical composition of Mt is 50.8%, 32.4%, 6.75%, 1.86%, 1.7%, 0.09%, 0.72% and 2.07% for O, Si, Al, Mg, Ca, K, Na and Fe, respectively, which was determinated by X-ray fluorescence. Sewage sludge sample was supplied by the Lijiao wastewater treatment, located in Guangzhou, China. Fe(NO₃)₃, Na₂CO₃, HF (40 wt%) and HCl (37 wt%) were purchased from Guangzhou Chemical Reagent Factory (Guangzhou, P. R. China). All the chemicals were of analytical grade and were used without further purification.

PVA (PVA-1799), acrylic acid (AA), 2-hydroxy-2-methylpropiophenone (I1173), ZrOCl₂·8H₂O, chitosan (deacetylation degree ≥ 95%, viscosity is 100–200 mPa·s), and ZnCl₂ were purchased from Shanghai Macklin Biochemical Co., Ltd. Agarose (high gel strength) and gelatin (gel strength ~250 g Bloom) were purchased from Shanghai Aladdin Bio-Chem Technology Co., Ltd. AlCl₃ was purchased from Sinopharm Chemical Reagent Co., Ltd. Gly, K₂CO₃, NaBr, KCl, CaCl₂, BaCl₂, MgCl₂, Na₂SO₄, NaCl, Na₃Cit, NaAc, Na₂HPO₄, and Na₂CO₃ were purchased from Guangzhou Chemical Reagent Factory. The deionized water was obtained using a water purification system.