Since compactness is a disadvantageous characteristic of chitosan-based membranes, two different methods were used to increase the porosity of the chitosan/poly(vinyl alcohol)/polyethyleneimine (CS/PVA/PEI) membrane, and its effect on copper ion adsorption was studied. In the first method, selective dissolution of poly(vinyl pyrrolidone) (PVP) induced porosity and for the second method, a mixed solvent system, which consists of a volatile solvent (acetone), was used to improve the porosity of the membrane. Different percentages of PVP showed inadequate performance, but acetone improved the operation efficiency of adsorption. The membranes were characterized by the analysis of FT-IR, SEM, BET, swelling degree, and porosity. Adding acetone to the membrane mixture solution increased the adsorption capacity by about 50%. The experimental results at different temperatures (25, 35, 45 and 55 °C) showed that the Cu²⁺ uptake was decreased with an increase in the temperature. Furthermore, pH had an important effect on the adsorption capacity of the copper ions. Nonlinear regression was applied to fit the isothermal and kinetic models. Reusability test with 0.05 M Na₂EDTA showed less than 8% reduction in adsorption capacity of the modified membrane after four cycles of adsorption–regeneration.

由于致密性是壳聚糖基膜的不利特性，因此使用两种不同的方法来增加壳聚糖/聚乙烯醇/聚乙烯亚胺（CS / PVA / PEI）膜的孔隙率，并研究了其对铜离子吸附的影响。在第一种方法中，聚乙烯吡咯烷酮（PVP）的选择性溶解会引起孔隙，而在第二种方法中，使用由挥发性溶剂（丙酮）组成的混合溶剂体系来改善膜的孔隙率。不同百分比的PVP表现出不足的性能，但是丙酮提高了吸附的操作效率。通过FT-IR，SEM，BET，溶胀度和孔隙率的分析来表征膜。在膜混合物溶液中加入丙酮可使吸附量增加约50％。随着温度的升高，2 ^+的吸收减少。此外，pH对铜离子的吸附容量有重要影响。应用非线性回归来拟合等温和动力学模型。用0.05 M Na ₂ EDTA进行的可重复使用性测试表明，经过四个吸附-再生循环后，改性膜的吸附能力降低了不到8％。