Polymeric ester thiourea resin (PDTU-I) is a new kind of chelating resin with functional atoms S, N and O, so it is an excellent adsorbent for noble metal ions. In batch testes, the adsorption capacities of PDTU-I for...Polymeric ester thiourea resin (PDTU-I) is a new kind of chelating resin with functional atoms S, N and O, so it is an excellent adsorbent for noble metal ions. In batch testes, the adsorption capacities of PDTU-I for Pt(IV) and Pd(II) increase with the increase of contact time, temperature and initial concentration of metal ions. The adsorption data fit Boyd's diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacities calculated by Langmuir equation are 2.54mmol/g for Pt(IV) and 4.88mmol/g for Pd(II). According to FTIR and XPS results, functional groups of PDTU-I coordinate with noble metal ions in the adsorption process.展开更多
Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacin...Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacing a nitrogen atom in the Pd(II) diimine catalyst with an oxygen atom from density functional theory method at the B3LYP/LANL2DZ level. The results show that the 1,2-insertion becomes a rival mechanism to the 2,1-insertion when the nitrogen atom is replaced by the oxygen atom leading to an asymmetric environment in the catalyst, and that the steric effect in the asymmetrical catalyst plays an important part in the polymerization. The insertion barrier from 2-O is much higher than that from 2-N. A pyramid transition state was characterized for the catalyst to convert 2-O back to 2-N through internal rotation. The propylene prefers to coordinate at the opposite side of O in the catalyst. This is the driving force for the internal rotation. The results are significant for isotactic and syndiotactic polymerization.展开更多
Treatment of precious metals in electronic waste has attracted tremendous attention and is essential for both environmental protection and resource sustainable development.In this study,a novel adsorbent for precious ...Treatment of precious metals in electronic waste has attracted tremendous attention and is essential for both environmental protection and resource sustainable development.In this study,a novel adsorbent for precious metal ions,V_(2)O_(3)spiny hollow nanospheres(pV_(2)O_(3)SHN),was synthe sized through a one-step hydrothermal-as sis ted methodology for the adsorption of Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ) from the leaching solution of electronic waste.The results reveal that the p-V2O3SHN hierarchy was successfully constructed with a hollow structure and dense spiny morphology.The prepared p-V2O3SHN can effectively remove precious metal ions such as Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ),with the selective capture order being Au(Ⅲ)> Ag(Ⅰ)> Pt(Ⅳ)> Pd(Ⅱ)> other metal ions.This superior adsorption capability can be attributed to the multi-diffusible,intermingled composition,and numerous active sites decorating the p-V2O3SHN hierarchy,facilitating the uptake of Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ) ions from electronic waste.The Langmuir model provided a better fit for the uptake process,revealing maximum uptake capacities of 833.33 mg/g for Au(Ⅲ),370.37 mg/g for Ag(Ⅰ),42.01 mg/g for Pd(Ⅱ),and 77.51 mg/g for Pt(Ⅳ) on p-V_(2)O_(3)SHN.Remarkably,p-V_(2)O_(3)SHN exhibited a robust affinity for the adsorbate due to the presence of surface defects and reduction reactions.The new p-V2O3SHN also demonstrated good reusability for three sorption cycles,highlighting its potential for electronic waste treatment.Due to its facile synthesis and excellent efficiency,hierarchical p-V2O3SHN presents itself as a promising candidate for the selective uptake of Au(Ⅲ),Ag(Ⅰ),Pt(Ⅳ),and Pd(Ⅱ) from electronic waste.展开更多
基金The National Natural Science Foundation of China(No.20476105)
文摘Polymeric ester thiourea resin (PDTU-I) is a new kind of chelating resin with functional atoms S, N and O, so it is an excellent adsorbent for noble metal ions. In batch testes, the adsorption capacities of PDTU-I for Pt(IV) and Pd(II) increase with the increase of contact time, temperature and initial concentration of metal ions. The adsorption data fit Boyd's diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacities calculated by Langmuir equation are 2.54mmol/g for Pt(IV) and 4.88mmol/g for Pd(II). According to FTIR and XPS results, functional groups of PDTU-I coordinate with noble metal ions in the adsorption process.
基金This work was supported by the Natural Science Foundation of Heilongjiang Province (No. B0313) and Research Foundation of China University of Mining and Technology
文摘Many attempts have been made to control the regioselectivity for olefin poly- merization by varying the structures of ligands in catalysts. The regioselectivity of propylene polymerization was investigated by replacing a nitrogen atom in the Pd(II) diimine catalyst with an oxygen atom from density functional theory method at the B3LYP/LANL2DZ level. The results show that the 1,2-insertion becomes a rival mechanism to the 2,1-insertion when the nitrogen atom is replaced by the oxygen atom leading to an asymmetric environment in the catalyst, and that the steric effect in the asymmetrical catalyst plays an important part in the polymerization. The insertion barrier from 2-O is much higher than that from 2-N. A pyramid transition state was characterized for the catalyst to convert 2-O back to 2-N through internal rotation. The propylene prefers to coordinate at the opposite side of O in the catalyst. This is the driving force for the internal rotation. The results are significant for isotactic and syndiotactic polymerization.
基金supported by the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.ES202306).
文摘Treatment of precious metals in electronic waste has attracted tremendous attention and is essential for both environmental protection and resource sustainable development.In this study,a novel adsorbent for precious metal ions,V_(2)O_(3)spiny hollow nanospheres(pV_(2)O_(3)SHN),was synthe sized through a one-step hydrothermal-as sis ted methodology for the adsorption of Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ) from the leaching solution of electronic waste.The results reveal that the p-V2O3SHN hierarchy was successfully constructed with a hollow structure and dense spiny morphology.The prepared p-V2O3SHN can effectively remove precious metal ions such as Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ),with the selective capture order being Au(Ⅲ)> Ag(Ⅰ)> Pt(Ⅳ)> Pd(Ⅱ)> other metal ions.This superior adsorption capability can be attributed to the multi-diffusible,intermingled composition,and numerous active sites decorating the p-V2O3SHN hierarchy,facilitating the uptake of Au(Ⅲ),Ag(Ⅰ),Pd(Ⅱ),and Pt(Ⅳ) ions from electronic waste.The Langmuir model provided a better fit for the uptake process,revealing maximum uptake capacities of 833.33 mg/g for Au(Ⅲ),370.37 mg/g for Ag(Ⅰ),42.01 mg/g for Pd(Ⅱ),and 77.51 mg/g for Pt(Ⅳ) on p-V_(2)O_(3)SHN.Remarkably,p-V_(2)O_(3)SHN exhibited a robust affinity for the adsorbate due to the presence of surface defects and reduction reactions.The new p-V2O3SHN also demonstrated good reusability for three sorption cycles,highlighting its potential for electronic waste treatment.Due to its facile synthesis and excellent efficiency,hierarchical p-V2O3SHN presents itself as a promising candidate for the selective uptake of Au(Ⅲ),Ag(Ⅰ),Pt(Ⅳ),and Pd(Ⅱ) from electronic waste.
