Synthesis, application and modelling of spherical magnetic silicon poly-N,N′-methylenebisacrylamide nanocomposite for effective copper removal from water

In this work, a new spherical magnetic silicon-substituted poly (N,N'-methylenebisacrylamide) (NSM) nanocomposite was synthesized, examined by various known instruments and applied as an adsorbent to eliminate copper (Cu²⁺) from its water solution using batch method experiment. The particles size of NSM composite was ranged from around 24.74 to 28.27 nm. The magnetic NSM nanocomposite are mesoporous, with specific surface area of 63.675 m² g^-1 and an average pore diameter of 7.6239 nm. The adsorption of Cu²⁺ ions was most efficient at a solution pH 5. The removal process using NSM nanocomposite has been studied in various settings, including initial Cu²⁺ ion concentration, initial pH, and temperature. Using an initial Cu²⁺ ions concentration (50 mg L^-1) and NSM nanocomposite dose (2.0 g L^-1), the maximum percent clearance of Cu²⁺ ions was 96.47%. The NSM's maximum adsorption capacity (Q_m) was 30.30 mg g^-1. Experimental data were discussed using the Langmuir (LIM), Freundlich (FIM), and Tempkin (TIM) isotherm models. The experimental data from NSM aligns effectively with the LIM model. Several error functions, such as Chi-Squared Error (X²), Average Percent Error (APE), Root Mean Square (RMS), Sum of Absolute Errors (EABS), Hybrid Error Function (HYBRID), and Marquardt's Percent Standard Deviation (MPSD), were applied to validate the isotherm model data. Calculations of the error function suggest that the LIM is the most appropriate for characterizing the adsorption process. Kinetic data were analyzed by fitting pseudo-first-order (PFOM), pseudo-second-order (PSOM), intraparticle diffusion (IPDM) and film diffusion (FDM) models. The PSOM rate model exhibited a robust correlation (R² > 0.998) and predominantly governed the adsorption rate. The results show that NSM effectively removes the Cu²⁺ ions from water. Utilizing a response surface methodology analysis to optimize the degradation parameters revealed that a maximum degradation percentage of 52.56 ppm of Cu²⁺ solution and 3.79 g of NSM could be achieved.