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1.
High efficient removal of mercury from aqueous solution by polyaniline/humic acid nanocomposite.
Zhang, Y, Li, Q, Sun, L, Tang, R, Zhai, J
Journal of hazardous materials. 2010;(1-3):404-9
Abstract
A composite sorbent PANI/HA was prepared by adding humic acid (HA) into chemical oxidation process of polyaniline (PANI). The sorbent was characterized by BET analysis, transmission electron microscopy, and FT-IR spectra. Batch adsorption results showed that the sorbent had high affinity to Hg(II) in aqueous solutions. The adsorption kinetics results of Hg(II) showed that the adsorption reached equilibrium within 200 min and adsorption rates could be described by pseudo-second-order kinetics. Sorption of Hg(II) to PANI/HA agreed well to the Langmuir adsorption model at different ionic strengths with the maximum adsorption capacity of 671 mg g(-1) (I=0.20 M). The experimental results showed solution pH values had a major impact on Hg(II) adsorption and with the help of HA the sorbent can effectively remove Hg(II) in a wide pH range (pH 4-7.5). An adsorption mechanism was proposed based on the XPS results.
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2.
Characterization and adsorption mechanism of Zn2+ removal by PVA/EDTA resin in polluted water.
Zhang, Y, Li, Y, Yang, LQ, Ma, XJ, Wang, LY, Ye, ZF
Journal of hazardous materials. 2010;(1-3):1046-54
Abstract
Batch adsorption experiments were conducted using a PVA/EDTA resin as an adsorbent to adsorb Zn(II) ions from single component system in which experimental parameters were studied including solution pH, contact time, adsorbent dose and initial metal ions concentration. The equilibrium isotherms were determined at pH 6 under constant ionic strength and at different temperatures. The results showed that the maximum removal of Zn(II) (99.8%) with 1 g L(-1) of sorbent was observed at 40 mg L(-1) at an initial pH value of 6. Removals of about 60-70% occurred in 15 min, and equilibrium was attained at around 30 min. The equilibrium data for the adsorption of Zn(II) on PVA/EDTA resin was tested with various adsorption isotherm models among which three models were found to be suitable for the Zn(II) adsorption. In addition, the kinetic adsorption fitted well to the pseudo-second-order model and the corresponding rate constants were obtained. Thermodynamic aspects of the adsorption process were also investigated. Furthermore a higher desorption efficiency of Zn(II) from the PVA/EDTA resin using acid treatment was available by more than 95%.
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3.
[Research development on disinfection technology for viruses in drinking water].
Zhang, Y, Zhang, Q, Liu, Y, Dai, R, Liu, X
Wei sheng yan jiu = Journal of hygiene research. 2010;(5):647-50
Abstract
With the deterioration of water source pollution, the quality requirements for drinking water of countries will become stricter and stricter, and the microbe index has been one of the important aspects. The introduction of the virus index and the development of disinfection technology focusing on virus have significant importance for the improvement of the drinking water standards and for the protection of people health in every country. To be familiar with the domestic and abroad research development of the disinfection control technology focusing on virus provides certain theory guidance and technological support for continuously improving drinking water standard in our country and for establishing safer drinking water processing technologies. So, this article will comprehensively describes 4 aspects: resistance comparison of virus over every disinfection technology, influential factors of disinfection, research development of new technology, and the mechanisms.
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4.
Optimization of Xhhh strain biodegradation with metal ions for pharmaceautical wastewater treatment.
Sun, SL, Wu, B, Zhao, DY, Zhang, XX, Zhang, Y, Li, WX, Cheng, SP
Journal of environmental biology. 2009;(5 Suppl):877-82
Abstract
Effects of three ions, Mn2+, Cu2+ and Zn2+ on biological treatment of pharmaceutical wastewaterby a functional strain Xhhh were investigated. Through orthogonal tests, Cu2+ was determined to be the most important factor influencing Xhhh biodegradation performance. Biodegradation kinetic experiments demonstrated that with Cu+ concentration at about 200 mg l(-1), the maximum of specific growth rate and specific degradation rate were obtained to be 0.033 and 0.075 d(-1), respectively. The optimal levels of Mn2+ (5.00 mg I(-1)), Cu2+ (2.00 mg l(-1)) and Zn2+ (5.00 mg l(-1)) were achieved based on experimental results of their effects on the activities of manganese peroxidase and lignin peroxidase, and biodegradation kinetic parameters. Among three types of biodegradation kinetic models (Monod, Tessier and Contois), Tessier model was found most reasonable for kinetics description of Xhhh growth (R2 = 0.995) and pollutants degradation (R2 = 0.970) in the case of metals optimization. Both kinetics evaluation and experimental results demonstrated that optimization with the three metals made a great contribution to Xhhh growth and COD removal for pharmaceutical wastewater treatment.
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5.
Bioremediation of contaminated surface water by immobilized Micrococcus roseus.
Li, H, Li, P, Hua, T, Zhang, Y, Xiong, X, Gong, Z
Environmental technology. 2005;(8):931-9
Abstract
The problems caused by contaminated surface water have gradually become more serious in recent years. Although various remediation technologies were investigated, unfortunately, no efficient method was developed. In this paper, a new bioremediation technology was studied using Micrococcus roseus, which was immobilized in porous spherical beads by an improved polyvinyl alcohol (PVA) - sodium alginate (SA) embedding method. The experimental results indicated that COD removal rate could reach 64.7 % within 72 hours when immobilized M. roseus beads were used, which was ten times as high as that of free cells. The optimum inoculation rate of immobilized M. roseus beads was 10 % (mass percent of the beads in water sample, g g(-1)). Suitable aeration was proved necessary to enhance the bioremediation process. The immobilized cells had an excellent tolerance to pH and temperature changes, and were also more resistant to heavy metal stress compared with free cells. The immobilized M. roseus beads had an excellent regeneration capacity and could be reused after 180-day continuous usage. The Scanning Electronic Microscope (SEM) analysis showed that the bead microstructure was suitable for M. roseus growth, however, some defect structures should still be improved.