With the rapid development of industry, copper metal pollution in wastewater discharged from related manufacturing fields has become increasingly serious.Meanwhile, demand for copper metal resources in the field of catalysis is increasing. In this study, low-cost modified calcium silicate hydrate (PCSH) was prepared using fly ash and modifier polyethyleneimine (PEI) for the adsorption of heavy metal copper ions(Cu(II)) in aqueous solution, and then the Cu(II), immobilized on the surface, was further treated with alkali to form copper-based active material for catalytic degradation of organic pollutants. Compared with unmodified sample (CSH), the maximum adsorption capacity of PCSH for Cu(II) was increased by 100% with the maximum of 588 mg/g. The main reason was that the addition of PEI facilitated formation of larger specific surface area, excellent pore structure and strong complexation between Cu(II) and -NH₂. The copper-based catalysts, which obtained from PCSH exhibiting spindle-shaped porous morphology, could catalyze the oxidative degradation of rhodamine B (RhB) by activating potassium peroxymonosulfate (PMS) and the reduction of 4-nitrophenol (4-NP) by activating sodium borohydride (NaBH₄), with rate constants of 0.7135/min (pH (7.0±0.3); [RhB]= 20 mg/L; [PMS]= 0.12 g/L; [catalyst]= 0.8 g/L) and 11.47×10^-3/s (pH (11.0±0.3); [4-NP]= 10^-4 mol/L; [NaBH₄]= 5×10^-3 mol/L; [catalyst]= 0.167 g/L), respectively, about 20 and 19 times as large as those of CSH catalyst system, respectively. The present work achieves the reuse of copper element in aqueous solution by using solid waste fly ash, which provides new insights into effective treatment and utilization of pollutants in water.