Highly selective adsorption of Pt(IV) from spent catalyst by polyethyleneimine functionalized polyethylene/polypropylene non-woven fabric

Aiming at efficient recovery of platinum (Pt) from aqueous solution, the aminated polyethylene/polypropylene non-woven fabric (PE/PP NWF) was synthesized via radiation grafting of glycidyl methacrylate (GMA), followed by ring-opening reaction with polyethyleneimine (PEI). The effects of different parameters, including pH, sorption time, initial Pt(IV) concentration, competing ions and adsorbent dosage on the Pt(IV) adsorption performance were investigated by batch adsorption tests. A high Pt(IV) adsorption capacity of 485.0 mg g⁻¹ (initial concentration: 263.5 mg L⁻¹) was achieved, and the adsorption kinetics and isotherm conformed to the pseudo-second-order model and the Langmuir isotherm model, respectively. Moreover, the PEI functionalized PE/PP NWF exhibited excellent adsorption performance over the wide pH range (1–6), and also good selectivity for Pt(IV) over multiple coexisting metal cations (Ni, Cu, Co, Pb, Mg, and Zn). The recovery ratio of Pt from spent proton exchange membrane fuel cell (PEMFC) catalysts reached 89.7% after three cycles of regeneration.     

Waste organic acid treatment with polyethyleneimine grafted polystyrene resin

Organic acid is a kind of important fine chemicals with wide application, while impropriate discharges would cause serious damage to environment. In this report, two polyethyleneimine (PEI-600, 1800) functionalized polystyrene (PS) resins were facilely prepared to remediate common organic acids. The heavier PEI-1800 resulted in surprisingly lower nitrogen loading of PSPEI under optimal conditions due to more significant extra grafting. Therefore, PSPEI-600 was used to adsorb two groups (aliphatic and aromatic) of eight common organic acids, and showed highest adsorptive capacities toward salicylic acid (SA) and trifluoroacetic acid (TFA). The adsorption of TFA was faster and was mainly due to strong acid–base interactions by forming ammonium carboxylate. SA possessed lower acidity, but its additional π-π stacking and hydrogen bonding interactions with the PSPEI resin led to a slower but overall higher uptake. Kinetic studies indicated that both acid adsorptions conformed to pseudo-second-order kinetics, and the adsorption rate was controlled by intraparticle diffusion. The adsorptions followed Langmuir isotherms and were identified as a spontaneous endothermic process.     

聚乙烯亚胺修饰坡缕石/CaIn2S4复合材料光催化降解甲基橙

以聚乙烯亚胺(PEI)修饰的坡缕石(PGS)[记为PGS(PEI)]、CaIn₂S₄前驱体为原料，一锅水热法制备了PGS(PEI)/CaIn₂S₄复合材料，通过XRD、SEM、N2吸附-脱附、UV-VisDRS及PL表征了复合材料的物化性能，阐述了该复合材料的生长机制，测试了PGS(PEI)/CaIn₂S₄复合材料光催化降解多种染料的可行性。结果表明，PGS(PEI)镶嵌在纳米花CaIn₂S₄的内部，PGS(PEI)质量分数为60%的PGS(PEI)/CaIn₂S₄复合材料[记为60%PGS(PEI)/CaIn₂S₄]的比表面积、孔容、孔径分别为138.59 m2/g、0.49 cm3/g、14.21 nm。PGS(PEI)与CaIn₂S₄之间的内置电场及PEI对光生电子的迁移提高了...