生物炭固定耐镉菌群对Cd2+的吸附及作用机制

从广西某硫化尾矿中分离出一耐镉菌群,将其固定在生物炭上制成固定化菌剂.同时,探究了生物炭种类、添加量、溶液pH、Cd²⁺初始浓度对固定化菌剂吸附Cd²⁺性能的影响,并结合吸附动力学、吸附等温线、16S rDNA、SEM、FTIR、XPS等分析测试手段研究了固定化菌剂对Cd²⁺的吸附过程和作用机制.结果表明,竹生物炭制备的固定化菌剂(ZBCM)对Cd²⁺的吸附效果最佳,在Cd²⁺浓度为20 mg·L^-1、pH=6、生物炭投加量为3 g·L^-1的条件下,ZBCM对Cd²⁺的吸附率达89.49%,较生物炭和单菌群的吸附率分别提高了54.6%和53.51%.从属水平上看,菌群主要由梭状芽孢杆菌、毛梭菌和产己酸菌构成,ZBCM吸附Cd²⁺后优势菌变为副梭菌、毛梭菌和贪铜菌,贪铜菌丰度的增长增强了ZBCM对Cd²⁺的络合和生物积累作用.ZBCM对Cd²⁺的吸附...     

紫外老化作用对纳米生物炭吸附环丙沙星的影响机制

纳米生物炭的老化行为在自然环境中是不可避免的,然而老化作用对纳米生物炭吸附污染物的影响机制尚不清楚.采用模拟光照老化,通过元素分析、扫描电镜、透射电镜和红外光谱分析老化前后纳米生物炭的组成和结构特性变化,探究了老化纳米生物炭对环丙沙星(CIP)的吸附机制以及溶液p H值和纳米生物炭浓度梯度对吸附的影响.结果表明,老化作用使纳米生物炭C元素含量降低,O元素含量增加,极性增强,芳香性和粒径降低.老化前后纳米生物炭对CIP的吸附在很大程度上取决于溶液p H值,酸性条件下溶液p H值的增加更有利于CIP的吸附.纳米生物炭浓度梯度影响研究表明,纳米生物炭在低浓度条件下更有利于CIP的吸附.老化前后纳米生物炭对CIP的吸附更符合准二级动力学模型,Langmuir模型能更好地描述CIP在老化前后纳米生物炭上的吸附行为,最大吸附量分别为607.69 mg·g^-1和920.73 mg·g^-1,老化纳米生物炭对CIP的吸附性能优于纳米生物炭,且主要的吸附机制为孔隙填充、静电作用和氢键作用.紫外老化作用增强了纳米生物炭对CIP的吸附性能.     

松嫩平原典型高氟区水库周边浅层地下水化学特征及高氟成因

高氟地下水极大地威胁水源安全,影响人体健康与生态环境.尽管近年来对高氟地下水开展了大量研究,但对水库周边浅层地下水中氟的地球化学背景、时空分布变化以及演变趋势仍缺乏系统认识.该研究综合运用数理统计、Arc GIS空间插值、Piper三线图、端元图、Gibbs图和MINTEQ地球化学模拟等方法,探讨吉林省向海水库浅层地下水中氟离子(F^-)的时空分布特征及影响机制.结果表明：(1)向海水库周边浅层地下水中F^-含量较高,浓度为0.20～5.18 mg?L^-1,平均浓度为1.76 mg·L^-1,高于我国《地下水质量标准》(GBT 14848—2017)中规定的1.00 mg?L^-1的浓度限值,属于高氟地下水,F^-浓度呈西北区域最高、东南次之、东北和西南最低的空间分布趋势;(2)该区域浅层地下水的水化学类型复杂,水化学特征以HCO₃-Na、HCO₃-Na·Ca和HCO₃-Na·Mg型为主;(3)F     

复合金属改性生物炭对水体中低浓度磷的吸附性能

通过FeCl_3和KMnO_4溶液对果壳生物炭进行浸渍改性,探索复合改性生物炭(Fe:Mn=1:1)对低浓度磷的吸附性能.结果表明,铁锰复合改性生物炭对低浓度磷的吸附效果远远大于铁改性及锰改性; SEM和FT-IR测定表明,铁锰复合改性后生物炭表面可能存在铁锰氧化物和铁氢氧化物.在磷浓度为0. 5 mg·L~(-1)、温度为298 K、固液比(mg∶L)为500时,吸附量为0. 96 mg·g~(-1).当溶液的pH为4～10,均具有较高的去除率和吸附量.等温吸附实验数据符合Freundlich方程,为多层吸附.吸附热力学研究表明,ΔG~θ0、ΔH~θ 0和ΔS~θ 0,说明该吸附是自发、熵增加的吸热过程.吸附动力学分析发现,改性后生物炭在60 min内基本达到吸附平衡,吸附过程符合准二级动力学方程,以化学吸附为主.可为天然水体和污水处理厂低浓度除磷提供理论数据支撑.     

不同生物炭对磷的吸附特征及其影响因素

为了实现植物生物质资源化利用,选择5种生物质材料制备生物炭,通过比较5种生物炭材料的磷吸附能力,筛选出了2种磷吸附效果较佳的材料,并探明了筛选生物炭材料的理化性质及其对磷的吸附特征.结果表明,5种生物炭材料中,仅水稻秸秆和玉米秸秆生物炭对磷具有吸附能力.Langmuir等温吸附曲线表明,水稻秸秆生物炭对废水中磷的吸附能力强于玉米秸秆生物炭,理论最大吸附量为：水稻秸秆生物炭(9.78 mg·g^-1)>玉米秸秆生物炭(0.39 mg·g^-1).水稻秸秆生物炭的比表面积(148.30 m²·g^-1)和总孔体积(0.11 cm³·g^-1)远高于玉米秸秆生物炭8.26 m²·g^-1和0.03 cm³·g^-1,同时水稻秸秆生物炭有更高的Mg、 Ca、 Fe和Al元素含量.水稻秸秆生物炭和玉米秸秆生物炭对磷吸附的最佳pH为酸性;在不同的pH范围内（3.0～11.0）,水稻秸秆生...     

KOH活化鱼鳞基生物炭的制备及其对VOCs的高效吸附去除研究

以废弃生物质罗非鱼鱼鳞为原料,用 KOH一步炭化活化法制备了鱼鳞基多孔生物炭,并借助 XRD、SEM、FTIR及 Boehm等方法对所制备生物炭的孔隙结构、形貌特征及表面化学性质进行表征 .结果表明：650 ℃条件下制备的生物炭（FSBC-1）表面含有最多的含氧基团,其中酚羟基含量为 0.3102 mmol·g^-1,而 850 ℃条件下制备的生物炭（FSBC-3）具备最高的比表面积(3370 m²·g^-1)和孔容(1.91 cm³·g^-1). 静态吸附实验表明,所制备生物炭对非极性分子甲苯的吸附过程符合 Langmuir模型,而 n-layer BET 模型能更好地描述材料对极性分子丙酮的吸附 .298 K条件下,FSBC-3 对 3 kPa 甲苯的吸附量高达 12.75 mmol·g^-1,对 20 kPa 丙酮的吸附量达 16.74 mmol·g^-1. 动态吸附实验和机理分析表明,对于低浓度VOCs,所制备生物炭对非极性分子甲苯的穿...     

铁改进型蓝藻生物炭的制备及对地表水中磷的协同吸附机制

为缓解水体富营养化以及蓝藻堆积问题,采用经过聚合硫酸铁(PFS)脱水后的蓝藻制备生物炭吸附水体中的磷酸盐,其中生物炭经过水蒸气活化调节孔隙结构.通过响应面法对蓝藻生物炭的制备条件进行优化.当PFS投加量为458 mg·L^-1、碳化温度为433℃和生物炭前体物与水蒸气的质量比为1∶11.选取不加PFS生物炭(F₀H₁₁-433)与加PFS生物炭(F₄₅₈H₁₁-43)进行X射线衍射(XRD)、傅里叶红外光谱(FTIR)、 Zeta电位和拉曼光谱(Raman)表征,来研究蓝藻生物炭与PFS对磷酸盐的去除是否具有协同效应.结果表明,与F₀H₁₁-433相比,F₄₅₈H₁₁-433表面出现铁氧化物,零电荷点(pH_pzc)从4.41提高到6.19,生物炭的无序、缺陷程度得到提高.准二级动力学模型和Langmuir模型适用于描述F₄₅₈H₁₁     

纳米零价铁改性生物炭对水中氨氮的吸附特性及机制

传统生物炭材料对水中氨氮(NH⁺₄-N)的吸附效果不佳.以生物炭为载体负载纳米零价铁制得生物炭基纳米零价铁复合吸附剂nZVI@BC,通过吸附实验,考察nZVI@BC对NH⁺₄-N的吸附特性,并采用SEM-EDS、 BET、 XRD和FTIR分析nZVI@BC的组成和结构特性,探讨nZVI@BC吸附NH⁺₄-N的主要机制.结果表明,在298K下铁/生物炭质量比为1∶30时制备的复合吸附剂(nZVI@BC1/30)对NH⁺₄-N的吸附性能最佳,比负载前生物炭的吸附量提高了45.96%,饱和吸附量可达16.60 mg·g^-1.伪二级动力学模型和Langmuir模型更符合nZVI@BC1/30对NH⁺₄-N的吸附过程.共存阳离子与NH⁺₄-N之间存在竞争吸附,其对nZVI@BC1/30吸附NH⁺     

过氧化钙/海泡石海藻酸钠缓释凝胶复合材料的制备及其对内源磷的控制性能

以载纳米过氧化钙海泡石为基本骨架,采用海藻酸钠包覆和镧离子交联研制了CPS60@SA/La复合材料,通过批量吸附实验和表征分析考察了其对富营养化水体中磷的去除效果及机制.结果表明,所制材料具有良好的释氧性和除磷能力,纳米过氧化钙和镧位点是其主要的活性组分.随着缓释凝胶用量增加,磷的去除率也相应增加;CPS60@SA/La对高浓度磷的去除过程符合准二级动力学模型和Langmuir吸附等温模型的描述,最大吸附容量为198.25 mg·g^-1 (20℃);CPS60@SA/La在p H 3～9范围内均对磷酸盐有良好的去除能力,F^-、HCO₃^-、CO₃^2-和HA的共存对CPS60@SA/La的除磷效果有轻微抑制作用;在实际河道水体中,该复合材料可缓慢释氧,保持水体溶解氧浓度大约为8.51 mg·L^-1,为泥水界面处的好氧微生物提供良好条件,对上覆水和间隙水中的磷酸盐均有良好的去除和固定能力,去除效果稳定,其使用有望提升水体自净能力.     

纤维氧化镁改性生物炭及其磷吸附研究

以农业废弃物花生壳为原料,在氯化镁、活性氧化镁水溶液中经陈化、热解得到纤维氧化镁改性生物炭(FMgO-BC).同时,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、比表面积分析(BET)等手段对FMgO-BC的组成、形貌进行了表征,并探索了FMgO-BC对磷废水的吸附动力学、颗粒内扩散、等温吸附及竞争吸附.结果表明,制备的FMgO-BC呈多孔结构且纤维状氧化镁交织嵌在生物炭表面,提供了大量的活性位点,同时,FMgO-BC呈规则、分层的孔隙结构,有利于吸附质的传输.在废水pH为3～10范围内,FMgO-BC对废水中磷酸盐具有较高的吸附能力.吸附动力学研究表明,FMgO-BC对磷酸盐的吸附复合准二级动力学模型,对于100 mg·L^-1的含磷废水在1 h即可达到吸附平衡.等温吸附拟合得到FMgO-BC的理论最大吸附量为625.63 mg·g^-1.FMgO-BC的磷吸附机理主要包括MgO质子化、静电吸附、络合等方式.因此,纤维氧化镁修饰生物炭能够显著提升生物炭对于废水中磷的吸附能力与速率.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.