Multiuse silicon hybrid polyurea-based polymer for highly effective removal of heavy metal ions from aqueous solution

Due to the growing quantities of numerous toxic and dangerous pollutants, wastewater has created increasing risks. Adsorp- tion is extensively implemented for various wastewater remediation processes owing to its facility, reasonable treatment quality, capable of a large range of adsorbents, and low-cost. Therefore, the in situ polymerization method was successfully used via the reaction of pyromellitic acid dianhydride (PMDA) and N-(3-(trimethoxysilyl) propylene ethylene diamine (TMSPEDA) followed by modification with toluene 2, 4-diisocyanate (TDI) for the synthesis of silicon hybrid polyurea- based polymer (SiHPUP). Due to its high selectivity, high thermal stability, and total insolubility in water, the hybrid poly- mer has been used as an outstanding sorbent for heavy metal ions [Co(II), Pb(II), and Cr(III)]. Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) have been used to characterize the hybrid sorbent (SiHPUP). Adsorption studies showed high adsorption of Cr(III) on SiHPUP, followed by Pd(II) and Co(II) at pH 7.5. The process was thermodynamically exothermic. The best-adapted models for the results were Langmuir and the pseudo-second-order kinetics model. Kinetic tests provide superior results at lower concentrations of SiHPUP for Cr(III) and Pd(II), while at higher concentrations, Co(II) adsorption was favourable. Highest elution of Pb(II) (94.3%)>Co(II) (92.4%) > Cr(III) (83.1%) with HCl (0.1 M) was demonstrated in desorption studies. The regeneration studies showed a 9, 10, and 16% loss in Cr(III), Co(II), and Pb(II) adsorption, respectively, on SiHPUP, after four consecutive cycles. Accord- ing to the findings, the fabricated silicon hybrid polyurea-based polymer provides a new insight and optimistic design for heavy metal wastewater purification.