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Huang J.,Central South University | Huang J.,New Mexico State University | Huang J.,Key Laboratory of Resources Chemistry of Nonferrous Metals | Yuan B.,New Mexico State University | And 2 more authors.
Journal of Colloid and Interface Science | Year: 2012

Adsorptive removal of aromatic compounds from aqueous solutions by polymeric adsorbents has attracted many concerns in recent years. A comparative adsorption study including equilibria, kinetics and column dynamics of β-naphthol from aqueous solutions was carried out using two hypercrosslinked polymeric adsorbents (HJ-1 and TEPA) we developed and two commercial polymeric adsorbents (XAD-4 and XAD-7). The adsorption isotherms could be well described by the Freundlich equation, and the adsorption equilibrium capacities of β-naphthol followed an order of q e(TEPA)>q e(HJ-1)>q e(XAD-4)>q e(XAD-7). The isosteric adsorption enthalpies on HJ-1 and TEPA decreased with increasing adsorption fractional loading, while a constant enthalpy was observed for XAD-4 and XAD-7, implying that HJ-1 and TEPA had a heterogeneous surface while XAD-4 and XAD-7 possessed a homogenous surface. The surface energetic heterogeneity of HJ-1 and TEPA could be well characterized by the Do's model. The adsorption kinetics were fitted by both pseudo-first-order and pseudo-second-order rate equations, and the intra-particle diffusion was found to be the rate-limiting step. The adsorption breakthrough data were well correlated by the Thomas and Clark models, and the dynamic capacities for TEPA, HJ-1, XAD-4 and XAD-7 adsorbents were calculated to be 341.7, 321.6, 268.0 and 173.8mg/g dry resin, which were within 90% of the corresponding equilibrium capacities obtained in the batch experiments. © 2012 Elsevier Inc. Source

Qiu Y.-R.,Central South University | Qiu Y.-R.,Key Laboratory of Resources Chemistry of Nonferrous Metals | Mao L.-J.,Central South University | Wang W.-H.,Central South University
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2014

Copolymer of maleic acid and acrylic acid (PMA-100), combining with polyvinyl butyral (PVB) ultrafiltration membrane was used for the removal of Mn(II) from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn(II) (n), pH, background electrolyte, etc on the rejection rate (R) and permeate flux (J) were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn(II) with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength. © 2014 The Nonferrous Metals Society of China. Source

Huang J.,Central South University | Huang J.,Key Laboratory of Resources Chemistry of Nonferrous Metals | Zha H.,Central South University | Jin X.,Central South University | Deng S.,New Mexico State University
Chemical Engineering Journal | Year: 2012

Phenol is a typical organic pollutant in industrial wastewater and efficient adsorptive removal of phenol from aqueous solution has attracted many attentions in recent years. In the present study, a diethylenetriamine-modified hypercrosslinked styrene-divinylbenzene (PS) resin, HJ-M05, was synthesized, characterized and evaluated for adsorptive removal of phenol from aqueous solution, and two typical commercial polymeric adsorbents, Amberlite XAD-4 and XAD-7, were employed as references. The equilibrium capacity on HJ-M05 was much larger than those on XAD-4, XAD-7 and the precursor, HJ-55. The degree of the surface energetic heterogeneity of HJ-M05 was proven to be higher than XAD-4 and XAD-7 while the adsorbate-adsorbate interaction of the adsorbed phenol molecules on HJ-M05 was much less than that on XAD-4 and XAD-7. The kinetic data on HJ-M05 could be well plotted by the micropore diffusion model while those on XAD-4 and XAD-7 could not be fitted by this model. Thomas and Yoon models were more suitable for describing the dynamic data than the Clark model and the dynamic capacities on HJ-M05, HJ-55, XAD-4 and XAD-7 were calculated to be 201.7, 178.1, 107.5 and 74.80. mg/g dry resin, respectively. 15.0. BV (1. BV = 10. ml) 1% of sodium hydroxide could regenerate the HJ-M05 resin column completely and the dynamic desorbed amount was almost equal to the dynamic adsorption amount. © 2012 Elsevier B.V. Source

Qiu Y.-R.,Central South University | Qiu Y.-R.,Key Laboratory of Resources Chemistry of Nonferrous Metals | Mao L.-J.,Central South University | Mao L.-J.,Key Laboratory of Resources Chemistry of Nonferrous Metals
Desalination | Year: 2013

Copolymer of maleic acid and acrylic acid (PMA-100), combining with polyvinyl butyral (PVB) hollow fiber ultrafiltration membrane were applied into a complexation-ultrafiltration process for the removal of heavy metal ions from an aqueous solution. Potentiometric and conductimetric titrations of the copolymer revealed that carboxylic group content was 9.5mmol.g-1 and the degree of deprotonation as pH was plotted. When low concentration (10mg/L) of solution containing heavy metal ion was processed, like Cu2+, Zn2+, Ni2+ and Mn2+, two most important factors (mass ratio of copolymer to metal and pH) were investigated and optimized to maximize both the rejection rate and permeate flux. The results show that at pH6.0 and copolymer/metal ratio 6-7 (w/w), the complexation is rapid and completed within 5min, reaching a removal efficiency above 98.8%. The copolymer could be efficiently regenerated by acidification-diafiltration and the residual concentration of Cu2+ in the concentrated copolymer solution decreased from 100mg/L to 2.6mg/L. In addition, the difference in binding ability to copolymer was studied and the relative affinity was Cu2+>Zn2+>Ni2+>Mn2+. The sequence is of great importance for guiding the selective separation of these metal ions in the future work. © 2013 Elsevier B.V. Source

Feng Q.,Central South University | Feng Q.,JiShou University | Liu S.,Central South University | Liu S.,Key Laboratory of Resources Chemistry of Nonferrous Metals | And 2 more authors.
Applied Surface Science | Year: 2012

A three-dimensional porous nanostructure electrode composed of copper skeletons and platinum shells (NPC-Pt) was prepared by electroless plating for the first time. The electrochemical behavior of this electrode for electrocatalytic reduction CO 2 in ionic liquid, 1-butyl-3- methylimidazoliumtetrafluoborate (BMIMBF 4), had been studied by cyclic voltammogram and electrochemical impedance spectroscopy with a reduction peak at -2.24 V (vs. Ag) which was more positive 180 mV than that obtained on a pure platinum electrode. The electrolyses experiments were carried out in an undivided cell under mild conditions without any toxic solvents, catalysts and supporting electrolytes, affording the dimethyl carbonate in a good yield (81%). In addition, the current for the CO 2 reduction at NPC-Pt electrode was stable, with a higher current density and current efficiency (83%). Moreover, current efficiency remained after reusing it for five times. © 2011 Elsevier B.V. All rights reserved. All rights reserved. Source

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