Preparation and evaluation of bis(diallyl alkyl tertiary ammonium salt) polymer as a promising adsorbent for phosphorus removal

Problems associated with water eutrophication due to high phosphorus concentrations and related environmentally safe solutions have attracted wide attention. A novel bis(diallyl alkyl tertiary ammonium salt) polymer, particularly poly(N~1,N~1,N~6,N~6-tetraallylhexane-1,6-diammonium dichloride)(PTAHDADC), was synthesized and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, mercury intrusion method, and thermogravimetric analysis. The adsorption characteristics in phosphorus were evaluated in dilute solution, and the recycling properties of PTAHDADC were investigated. Results showed that PTAHDADC possessed macropores with a size distribution ranging from 30 to 130 μm concentrating at 63 μm in diameter and had 46.52% of porosity, excellent thermal stability below 530 K, and insolubility. PTAHDADC could effectively remove phosphorus at p H = 7–11 and had a removal efficiency exceeding 98.4% at pH = 10–11. The adsorption equilibrium data of PTAHDADC for phosphorus accorded well with the Langmuir and pseudo-second-order kinetic models. Maximum adsorption capacity was 52.82 mg/g at 293 K. PTAHDADC adsorbed phosphorus rapidly and reached equilibrium within 90 min. Calculated activation energy Eawas 15.18 k J/mol. PTAHDADC presented an excellent recyclability with only 8.23% loss of removal efficiency after five adsorption–desorption cycles. The morphology and structure of PTAHDADC slightly changed as evidenced by the pre-and post-adsorption of phosphorus, but the process was accompanied by the partial deprotonation of the(–CH_2)_3-NH~+ group of PTAHDADC. The adsorption was a spontaneous exothermic process driven by entropy through physisorption, electrostatic attraction, and ion exchange. Survey results showed that PTAHDADC was a highly efficient and fast-adsorbing phosphorus-removal material prospective in treating wastewater.     

安徽沿江地带投资环境综合研究

改善投资环境吸引外资是经济发展的重要内容。安徽沿江地带是长江经济带重要的组成部分，对安徽沿江地带投资环境进行了分析与评价，并就进一步完善沿江地带宏观投资环境，推动经济联合发展提出了建议与措施。     

黄山贫困山区资源特点与治贫开发对策

黄山是我国十大风景名胜区之一，但全区经济发展水平十分落后，属安徽省贫困地区之一。本文对黄山贫困山区的资源特点与存在问题进行了综合分析，指出了本区贫困落后的主要原因，并就治贫开发提出了相应对策。     

Photoelectro-Fenton mineralization of phenol through optimization of ferrous regeneration

The degradation of phenol in acidic solution at pH 3 has been investigated under various photo- and electrochemical conditions. A laboratory-scale reactor on which were mounted net electrodes (RuO₂/IrO₂-coated Ti anodes (DSA) and stainless steel cathodes) and 254 nm UV lamps was established to effectively reduce ferric reagents. The experimental results of the photoelectron-chemical reaction suggested that the current efficiency of reducing ferric ion was improved by increasing the number of electrodes used, and the UV lamps were important to inducing the reduction of ferric carboxylates, which were the major intermediates that were formed upon a particular degree of phenol oxidation. Accordingly, the addition of an initial concentration of 400 ppm ferrous salt and 10,200 ppm hydrogen peroxide (in a continuous mode) resulted in the removal of over 92 % of TOC (initial phenol?=?2,000 ppm, TOC?=?1,532 ppm) by 4 h of the photoelectro-Fenton and the sequential 2 h of the photo-Fenton processes. HPLC was utilized to monitor the formation of aromatic and carboxylate byproducts, and revealed that the aid of photo irradiation eliminated most of the oxalate residue from the final solution, which would have contributed to the 25 % of the TOC that was inactive in the electrolytic system.     

Application of surface molecular imprinting adsorbent in expanded bed for the adsorption of Ni(2+) and adsorption model

A new surface molecular imprinting adsorbent (SMIA) was used in an expanded bed. The expansion ratio and adsorption performance were studied at different volumetric rates, inlet concentrations, and pH values. A model based on the Adams-Bohart adsorption model of breakthrough curves was established. The predicted curves had good agreement with the experimental curves. The breakthrough time (T(1/2)) decreased with increasing inlet concentration when the outlet concentration was half the initial concentration (C/C(0)=0.5). The inlet concentration had little effect on the adsorption rate constant (k(1)) value when the initial concentration (C(0)) was above 150 mg/L. However, T(1/2) values increased with increasing initial pH of the inlet solution, and the k(1) value decreased due to the competition between H(+) and Ni(2+).     

纳米银和PVP包被纳米银对HepG2细胞遗传毒性的比较研究

为了探讨纳米银对HepG2细胞DNA损伤、染色体畸变等遗传毒性指标的影响,以期为纳米银体外遗传毒性评价提供参考依据,本文采用2种纳米银材料(20 nm-PVP包被纳米银、20 nm-无包被纳米银),分别以20μg·mL~(-1)、40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)的剂量对HepG2细胞染毒24 h,用Hoechst-33258染色法检测细胞凋亡,彗星实验检测DNA损伤,胞质分裂阻滞微核细胞组学试验法检测染色体畸变。结果表明,20 nm Ag NPs组在160μg·mL~(-1)时引起细胞凋亡数显著增多(P0.05);20 nm PVP-Ag NPs组在80μg·mL~(-1)和160μg·mL~(-1)剂量组中细胞凋亡数显著增多(P0.01)。2种纳米银引起HepG2细胞发生细胞凋亡,并呈剂量效应关系。彗星试验结果表明,20 nm Ag NPs和20 nm PVP-Ag NPs在40μg·mL~(-1)、80μg·mL~(-1)、160μg·mL~(-1)剂量组中,Olive尾矩、尾长和尾部DNA百分比与空白对照组相比均有显著差异(P0.05)。2种纳米银对HepG2细胞DNA损伤程度为:20 nm Ag NPs20 nm PVP-Ag NPs。胞质分裂阻滞微核细胞组学试验结果表明,2种纳米银均不会引起核质桥数发生明显改变(P0.05),20 nm Ag NPs在高染毒剂量下引起微核总数、I型微核、II型微核、核芽数明显升高(P0.05);20 nm PVP-Ag NPs在各染毒剂量下均会引起微核总数及I型微核数量升高(P0.01),II型微核数在160μg·mL~(-1)剂量下升高明显(P0.01),剂量大于20μg·mL~(-1)时核芽数升高(P0.01)。20 nm PVP-Ag NPs对细胞核的影响大于20 nm Ag NPs(P0.05)。总之,2种纳米银材料均会引起HepG2细胞DNA损伤及染色体畸变等遗传毒性效应的改变,无包被纳米银比PVP包被纳米银更容易引起DNA损伤,PVP包被纳米银比无包被纳米银更容易引起细胞染色体畸变相关效应;2种材料对HepG2细胞的损伤存在浓度-效应关系,浓度越高遗传毒性损伤越严重。     

Fabrication and photocatalytic ability of an Au/TiO<Subscript>2</Subscript>/reduced graphene oxide nanocomposite

A new type of Au/TiO₂/reduced graphene oxide (RGO) nanocomposite was fabricated by the hydrothermal synthesis of TiO₂ on graphene oxide followed by the photodeposition of Au nanoparticles. Transmission electron microscopy images showed that Au nanoparticles were loaded onto the surface of both TiO₂ and RGO. Au/TiO₂/RGO had a better photocatalytic activity than Au/ TiO₂ for the degradation of phenol. Electrochemical measurements indicated that Au/TiO₂/RGO had an improved charge transfer capability. Meanwhile, chemiluminescent analysis and electron spin resonance spectroscopy revealed that Au/TiO₂/RGO displayed high production of hydrogen peroxide and hydroxyl radicals in the photocatalytic process. This high photocatalytic performance was achieved via the addition of RGO in Au/TiO₂/RGO, where RGO served not only as a catalyst support to provide more sites for the deposition of Au nanoparticles but also as a collector to accept electrons from TiO₂ to effectively reduce photogenerated charge recombination.

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