Applied Sciences  
Polyethylenimine-Modified Magnetic Chitosan for the Uptake of Arsenic from Water  
[PERSON], [PERSON],*2, [PERSON],*2, [PERSON],*3,*4, [PERSON] and [PERSON]  
Chemistry Department, College of Science, Princess Nourah hint Abdulrahman University,  
Riyadh 11671, Saudi Arabia; [EMAIL_ADDRESS]  
Department of Chemical Engineering, College of Engineering, King Khalid University,  
Abha 6411, Saudi Arabia  
Research Laboratory of Energy and Environment, Department of Chemical Engineering, National School of Engineers, Gables University, Gables 6072, Tunisia  
Higher Institute of Biotechnology of Sfax (ISBS), Sfax University, P.O. Box 263, Sfax 3000, Tunisia; [EMAIL_ADDRESS]  
Department of Chemistry, College of Science, King Khalid University, P.O. Box 9004,  
Abha 64113, Saudi Arabia; [EMAIL_ADDRESS]  
Chemistry Department, Faculty of Science, Mansoura University, Mansoura 35516, Egypt  
Coregonbendence: [EMAIL_ADDRESS] (F.M.A.A.); [EMAIL_ADDRESS] (K.M.K.); [EMAIL_ADDRESS] (A.A.)  
The removal of heavy metals from water has become a global environmental problem. Various materials have been applied as adsorbent to remove metals from water. In this field, nanomaterials have been gaining increasing interest due to their exceptional properties. In this work, we discuss the synthesis of a core-shell structure nanocomposite by the modification of magnetic chitosan (CS) (Fe\({}_{3}\)O\({}_{4}\)/CS) with polyethyleneimine (PEI) to produce Fe\({}_{3}\)O\({}_{4}\)/CS/PEI composite for the adsorption of arsenic ions (As(V) and As(III)) from aqueous solution. The synthesized materials were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM). The results indicated the successful combination of three components of the nanocomposite. The adsorption conditions were optimized by studying the effect of different parameters included pH, contact time, initial concentration, and adsorbent dosage. The optimum adsorption pH was found to be 6.7 while the optimum adsorbent dosage was found to be 2.0 and 1.5 g/L for As(III) and As(V), respectively. The removal efficiency for the uptake of As(III) and As(V) ions over Fe\({}_{3}\)O\({}_{4}\)/CS/PEI nanocomposite at optimum conditions was found to be 99.5 and 99.7%, respectively. The experimental results were fitted using [PERSON]'s and [PERSON]'s isotherms. The data were more fitted to [PERSON] isotherm providing a suggestion of monolayer adsorption with maximum adsorption capacity equal to 77.61 and 86.50 mg/g for the removal of As(III) and As(V), respectively. Moreover, linear regression coefficient (R\({}^{2}\)) indicated that the adsorption of arsenic ions over the synthesized magnetic nanocomposite obeyed pseudo 2 nd order suggesting the chemisorption process. The reusability of the nanosorbent for arsenic uptake using sodium hydroxide as eluent was also assessed up to five cycles. Interestingly, Fe\({}_{3}\)O\({}_{4}\)/CS/PEI nanocomposite can be considered as a promising adsorbent for As ions' removal from water and should be tested for the removal of other pollutants.  
magnetic nanomaterials; arsenic removal; adsorption; core-shell structures +
Footnote †: journal: Applied Sci. 2021, 11, 5630. [[https://doi.org/10.3390/app11125630](https://doi.org/10.3390/app11125630)]([https://doi.org/10.3390/app11125630](https://doi.org/10.3390/app11125630))