Purification of starch and phosphorus wastewater using core-shell magnetic seeds prepared by sulfated roasting

Core-shell magnetic seeds with certain adsorption capacity that were prepared by sulfated roasting, served as the core of a magnetic separation technology for purification of starch wastewater. XRD and SEM results indicate that magnetite's surface transformed to be porous α-Fe_2O_3 structure. Compared with magnetite particles, the specific surface area was significantly improved to be 8.361 from 2.591 m~2/g, with little decrease in specific susceptibility. Zeta potential, FT-IR and XPS experiments indicate that both phosphate and starch adsorbed on the surface of the core-shell magnetic seeds by chemical adsorption, which fits well with the Langmuir adsorption model. The porous surface structure of magnetic seeds significantly contributes to the adsorption of phosphate and starch species, which can be efficiently removed to be 1.51 mg/L(phosphate) and 9.51 mg/L(starch) using magnetic separation.     

Photocatalytic activity of TiO2 containing anatase nanoparticles and rutile nanoflower structure consisting of nanorods

A series of TiO2 with different crystal phases and morphologies was synthesized via a facile hydrothermal process using titanium nbutoxide and concentrated hydrochloric acid as raw materials. The photocatalytic activity of the samples was evaluated by degradation of Methyl Orange in aqueous solution under UV-Visible light irradiation. On the basis of detailed analysis of the characterizing results of high-resolution transmission electron microscopy, X-ray powder diffraction measurements, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement, it was concluded that the photo-activity of the catalyst is related directly to the 3D morphology and the crystal phase composition. An excellent catalyst should have both a futile 3D flower-like structure and anatase granulous particles. The 3D flower-like structure could enhance light harvesting, as well as the transfer of reactant molecules from bulk solution to the reactive sites on TiO2. In addition, the optimum anatase/rutile phase ratio was found to be 80：20, which is beneficial to the effective separation of the photogenerated electron-hole pairs.     

Simultaneous determination of brominated phenols in soils

Brominated phenols （BPs）, a widely used group of emerging flame retardants, are important environmental contaminants and exhibit endocrine disrupting potential. Method for simultaneous determination of tetrabromobisphenol A （TBBPA）, tribromophenol （TBP）, dibromophenols （DBPs） and monobromophenols （MBPs） in soils using gas chromatography-mass spectrometry analysis （GC/MS） was successfully developed. Cleanup methods for soil extracts including several solid-phase extraction cartridges and different elution solvents were compared and optimized. Florisil cartridge with dichloromethane as the elution reagent was selected for sample cleanup owing to its high and reproducible recoveries of the target analytes in soils. Derivatization conditions were tested and the optimal conditions were obtained with 20 μL silylation reagent at room temperature. The chromatographic separation was optimized with different columns and DB-XLB column was selected for its excellent separation of the analytes. The limits of detection for the target compounds were from 0.04 to 0.19 ng/g. Mean recoveries of the compounds from spiked soils exceeded 84% with a good reproducibility, excepting that the recovery of 2-bromophenol was relatively poor （lower than 55%） due to its instability. The developed method was applied to the determination of the BPs in the soils collected from e-waste sites. The contents of BPs in the soils were at ng/g levels with TBBPA and TBP the most frequently detected. To our knowledge, this is the first report for the simultaneous determination of TBBPA, TBP, DBPs and MBPs in soils.     

One-step synthesis of Cu(II) metal–organic gel as recyclable material for rapid, efficient and size selective cationic dyes adsorption

Efficient removal of non-biodegradable and hazardous dyes from wastewater remains a hot research topic. Herein, a rationally designed a Cu(Ⅱ)-based metal–organic gel(Cu-MOG) with a nanoporous 3 D network structure prepared via a simple one-step mixing method was successfully employed for the removal of cationic dyes. The Cu-MOG exhibited high efficiency, with an adsorption capacity of up to 650.32 mg/g, and rapid adsorption efficiency, with the ability to adsorb 80% of Neutral Red within 1 min. The high adsorption efficiency was attributed to its large specific surface area, which enabled it to massively bind cationic dyes through electrostatic interaction, and a nanoporous structure that promoted intra-pore diffusion. Remarkably, the Cu-MOG displayed size-selective adsorption, based on adsorption studies concerning dyes of different sizes as calculated by density functional theory. Additionally, the adsorption performance of the Cu-MOG still maintained removal efficiency of 100% after three regeneration cycles. These results suggested that the Cu-MOG could be expected to be a promising and competitive candidate to conveniently process wastewater.     

17α-Ethynylestradiol biodegradation in different river-based groundwater recharge modes with reclaimed water and degradation-associated community structure of bacteria and archaea

This study investigated 17α-ethynylestradiol(EE2) biodegradation process and primary metabolic pathways associated with community structures of microorganism during groundwater recharge using reclaimed water. The attenuation rate is 1.58 times higher in wetting and drying alternative recharge(WDAR) than in continual recharge(CR). The primary biotransformation pathways of EE2 in WDAR system began with the oxidation of C-17 on ring D to form a ketone group, and D-ring was subsequently hydroxylated and cleaved. In the CR system, the metabolic pathway changed from the oxidation of C-17 on ring D to hydroxylation of C-4 on ring A, and ring A or B subsequently cleaved; this transition was related to DO, and the microbial community structure. Four hundred fifty four pyrosequencing of 16 s r RNA genes indicated that the bacterial communities in the upper layer of the WDAR system were more diverse than those found in the bottom layer of the CR system; this result was reversed for archaea. Unweighted Uni Frac and taxonomic analyses were conducted to relate the change in bacterial community structure to the metabolic pathway. Microorganism community diversity and structure were related to the concentrations of dissolved oxygen, EE2 and its intermediates in the system. Five known bacterial classes and one known archaeal class, five major bacterial genera and one major archaeal genus might be involved in EE2 degradation. The findings of this study provide an understanding of EE2 biodegradation in groundwater recharge areas under different recharging modes and can facilitate the prediction of the fate of EE2 in underground aquifers.     

Insight into selective removal of copper from high-concentration nickel solutions with XPS and DFT: New technique to prepare 5N-nickel with chelating resin

An efficient and profitable separation process was proposed to prepare 5N(the purity of the metal solution reaches 99.999%) high-purity nickel from 3N nickel-solutions using Purolite S984. The adsorption performance of this superior resin, especially its selectivity for metal ions,was explored quantitatively. The maximum adsorption capacity for copper was 2.286 mmol/g calculated by the Langmuir model, which was twice as large as that for nickel. In the binary systems, the adsorption capacity for nickel was decreased by 45%, indicating direct competition for the active sites. The infinite separation factor for copper versus nickel exceeded 300, revealing the feasibility of preparing5N-level high-purity nickel solutions, which was further verified using the 800 BV(bed volume) effluent in the column dynamic process.According to the cost–benefit analysis, purification contributed to a profit of approximately 60,000 USD per cycle, and the investment return period was less than 1/3 years. Density functional theory analysis confirmed that four nitrogen atoms would be involved in the coordination complex and thus a structure involving two five-membered rings could be achieved. The X-ray photoelectron spectra confirmed the involvement of nitrogen atoms,implying a coordination ratio of approximately 1:1.     

Isolation and characterization of a profenofos degrading bacterium

Profenofos, a well known organophosphate pesticide, has been in agricultural use over the last two decades for controlling Lepidopteron pests of cotton and tobacco crops. In this study, a bacterial strain, OW, was isolated from a long term profenofos exposed soil by an enrichment technique, and its ability to degrade profenofos was determined using gas chromatography. The isolated strain OW was identified as Pseudomonas aeruginosa according to its physiological and biochemical properties, and the analysis of its 16S rRNA gene sequence. The strain grew well at pH 5.5–7.2 with a broad temperature profile. Bioremediation of profenofos-contaminated soil was examined using soil treated with 200 g/g profenofos, which resulted in a higher degradation rate than control soils without inoculation. In a mineral salt medium (FTW), removal in the level of profenofos of 86.81% was obtained within 48 h of incubation. The intermediates of profenofos metabolism indicated that the degradation occurred through a hydrolysis mechanism, and one of the metabolites was found to be 4 bromo-2-cholorophenol (BCP) which in turn was also mineralized by the strain. The results of this study highlighted the potentiality of P. aeruginosa as a biodegrader which could be used for the bioremediation of profenofos contaminated soil.     

Anoxic biodegradation of dimethyl phthalate （DMP） by activated sludge cultures under nitrate-reducing conditions

Worldwide extensive use of plasticized plastics has resulted in phthalates pollution in different environment. Nitrates from industry and agriculture are also widely disseminated in the soils, natural waters and wastewaters. Dimethyl phthalate (DMP) biodegradation by activated sludge cultures under nitrate-reducing conditions was investigated. Under one optimized condition, DMP was biodegraded from 102.20 mg/L to undetectable level in 56 h under anoxic conditions and its reaction fitted well with the first-order kinetics. Using the high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS) analysis, mono-methyl phthalate (MMP) and phthalic acid (PA) were detected as the major intermediates of DMP biodegradation. When combined with the determination of chemical oxygen demand (CODCr) removal capacity and pH, DMP was found to be mineralized completely under anoxic conditions. The biodegradation pathway was proposed as DMP → MMP → PA → … → CO2 H2O.The molar ratio of DMP to nitrate consumed was found to be 9.0:1, which agrees well with the theoretical stoichiometric values of DMP biodegradation by nitrate-reducing bacteria. The results of the non-linear simulation showed that the optimum pH and temperature for the degradation were 7.56 and 31.4℃, respectively.     

Isolation and characterization of a thermophilic Bacillus shackletonii K5 from a biotrickling filter for the production of polyhydroxybutyrate

Polyhydroxyalkanoates（PHAs） are aliphatic polyesters accumulated intracellularly by both Gram-negative and Gram-positive bacteria. However, compared to the PHAs of Gramnegative bacteria, few endotoxins（lipopolysaccharides, LPS）, which would be co-purified with PHAs and cause immunogenic reactions, are found in the PHAs produced by Gram-positive bacteria. A thermophilic Gram-positive bacterium K5, which exhibited good growth and polyhydroxybutyrate（PHB）-accumulating ability, has been isolated and characterized from a biotrickling filter designed for the removal of NOx from flue gas in a coal-fired power plant in China. Based on the biochemical characterization and 16 S rRNA gene sequence（Genbank accession no. JX437933）, the strain K5 has been identified as Bacillus shackletonii, which has rarely been reported in the literature, and this report is the first time that B. shackletonii has been found to accumulate PHB. The strain K5 was able to utilize glucose as carbon source to synthesize PHB at a broad range of temperatures（from 35 to 50 °C）, and the ideal temperature was 45 °C. The strain K5 could effectively yield PHB of up to 69.9% of its cell dry weight（CDW）（2.28 g/L） in flask experiments employing glucose as carbon source at 45 °C, followed by 56.8% and 52.3% of its CDW when using sodium succinate and glycerol as carbon source, respectively. For batch cultivation, the strain K5 was able to produce PHB of up to 72.6% of its cell dry weight（9.76 g/L） employing glucose as carbon source at 45 °C and pH 7.0.     

Properties and coagulation mechanisms of polyferric silicate sulfate with high concentration

Polyferric silicate sulfate （PFSS） with high concentration was prepared using the composite-poly method. The coagulation properties and mechanisms of this new complex were probed using TEM, Fe-Ferron timed complex-colorimetric method, and infrared spectrum method. The results showed that the flocculating effect of polyferric silicate sulfate had an advantage over polyferric sulfate （PFS）, as the optimum coagulation effect could be obtained when the Si/Fe mole ratio was 0.75 in accordance with its macrostructure of PFSS. According to the Fe-Ferron timed complex-colorimetric method, the Si species was mainly Sic, whereas, the Fe species were Fea and Fec in the copolymerization system. The infrared spectra indicated that the structure of these new flocculants was formed by polymers, mainly by olation, which was different from polyferric sulfate, and the vibration of M-OH-M of around 1100 cm^-1, also proved that there existed Fe-OH-Fe and its polymers in some forms.     

纳滤膜组合工艺去除饮用水中可同化有机碳和致突变物

分别以太湖水和淮河水为水源的两地水厂出厂水为研究对象，研究纳滤膜组合工艺对饮用水中可同化有机碳和致突变物的去除效果。研究表明，纳滤膜对可同化有机碳的去除率为80%，能确保饮用水的生物稳定性。对致突变物的去除率大于90%。使Ames实验结果由阳性转为阴性。对两地不同原水均能生产出安全优质的饮用水。     

溶液吸收/分光光度法检测空气中偏二甲肼含量

GJB2373-95采用固体吸附/分光光度法监测空气中偏二甲肼,但是采集空气中偏二甲肼所用的SG-2固体吸附剂和采样管制作繁琐,分析步骤复杂,不适合连续监测。文章以单位自行研制的偏二甲肼动态配气系统配制已知浓度空气样品为测试环境,用标定过的美国Interscan气体检测仪实时监测其浓度为13.4×10-6～13.6×10-6,采用溶液吸收法采样并简化GJB2373-95标准方法的分析步骤。依据两种方法分别做出各自的标准曲线,并采用固体吸附法和溶液吸收法各采集两个平行样,样品采样体积分别为3.28L、3.31L和3.12L、3.14L,对应各自的标准曲线,计算出两组样品偏二甲肼含量分别为10.7×10-6、11.0×10-6和12.1×10-6、12.0×10-6。经传感器实时监测值作为第三方数据比对,结果表明溶液吸收/分光光度法监测结果准确,分析步骤简单、省时。     

二氧化氯氧化法处理偏二甲肼污水工艺

利用二氧化氯氧化法处理含偏二甲肼的污水,通过实验数据分析初步确定二氧化氯氧化偏二甲肼的化学反应机理。采取二氧化氯多级串联氧化法,再通过活性炭吸附柱处理含偏二甲肼的污水。偏二甲肼与二氧化氯的摩尔之比控制在1:9~1:11,并采取多级氧化塔串联方式,可提高二氧化氯的氧化效率与利用率。对于发射场的实际污水处理工艺条件为偏二甲肼/ClO2摩尔投料比:1:9;氧化温度:15℃;陈化时间:15d;污水通过Φ25×400吸附柱(100g活性炭)流量3mL/min。处理后的污水各项指标符合GB8978-1996污水综合排放标准。     

活性炭-纳滤膜工艺去除饮用水中总有机碳和Ames致突变物

分别以地表水和地下水为水源的水厂出水为研究对象 ,探讨活性炭 纳滤膜工艺对饮用水中总有机碳和Ames致突变物的去除效果及机理 .结果表明 ,活性炭的吸附作用受其本身性质和有机物特性影响较大 ,去除能力有限 ,但它可作为纳滤的预处理 ,确保膜进水符合要求 ;纳滤则可将水中总有机碳和Ames致突变物大部分去除 ,使TA₉₈及TA₁₀₀菌株在各试验剂量下的MR值均小于 2 ,Ames试验结果均完全呈阴性 ,确保了饮用水的安全性 .两者的组合是获得优质饮用水的有效处理工艺 .     

不同组合净水工艺对水中致突变物的去除

对５种组合净水工艺的出水及原水进行Ａｍｅｓ试验,结果显示,生物陶粒能部分去除水中直接致突变有机物,降低原水的ＭＲ比值,ＴＡ９８菌株ＭＲ比值在剂量为１Ｌ／皿水样及０．５Ｌ／皿水样时,分别比原水减少了４０．２％及４１．９％。     

NF和RO对致突变物和无机离子去除效果比较

以自来水为原水,采用反渗透和纳渗进行深度处理试验研究,比较了２种膜对致突变物和无机离子的去除率。结果表明,ＲＯ和ＮＦ均能使Ａｍｅｓ试验呈阳性的水转变为阴性;ＮＦ对一价阳离子（Ｋ＾＋、Ｎａ＾＋）的去除率比ＲＯ低１０％左右,对二价阳离子（Ｃａ＾２＋、Ｍｇ＾２＋）的去除率略低于ＲＯ,ＮＦ比ＲＯ能多保留一些离子。     

有限信息下对排污者进行管理的一种激励机制

管理者和排污者之间的信息不对称是环境管理的一大障碍 .应用激励机制设计理论设计了有限信息下应用排污收费对排污者进行管理的一种激励机制 .这种机制将起到激励真实信息的作用 ,利于减少管理成本 .     

光催化降解模拟室内挥发性有机污染物研究

用浸渍-提拉法制备玻璃弹簧负载型TiO2薄膜催化剂,在自制的反应器中进行光催化降解由丙酮、甲苯、对二甲苯组成的模拟室内挥发性有机污染物VOCs研究。研究发现：催化剂中掺杂金属离子能影响催化剂的降解效果,降解效果依次为掺铈TiO2〉纯TiO2〉掺银TiO2;气体流量显著影响降解效果,丙酮、甲苯和对二甲苯的最佳降解流量分别为3、5、7L／min;混合气体中非对称性的极性分子的降解效率高于对称性分子,导致丙酮、对二甲苯组分降解率降低,甲苯降解率增高。     

皂素清洁生产工艺的研究(Ⅰ)

黄姜淀粉经过!-淀粉酶液化,加糖化酶和酵母进行边糖化边发酵生产酒精。发酵后黄姜渣用酸水解法提取薯蓣皂素。黄姜淀粉利用率为86.30%,耗酸量为传统工艺的55%,废水的总COD比传统工艺减少了60.25%,皂素收率比传统工艺提高20.37%。     

主动脉动气流分选处理废弃催化剂

废弃催化剂重整后含有富集贵金属的海绵体和烧结磁珠,二者的有效分选是提纯贵金属富集体的重要环节。主动脉动气流分选装置能够对此物料进行干法分选,避免了湿法分选对物料的改性,有利于贵金属富集体的后续提纯。介绍了主动脉动气流分选装置的结构,分析主动脉动气流分选机理及其动力学模型。通过实际物料进行分选试验。结果表明,在脉动频率为7/3 Hz,气流流速为2.50~6.00 m/s时,总分选效率Ef高于94.50%;在气流流速为3.33 m/s时,分选效率最高,总分选效率Ef可达97.63%。