Biosorption of heavy metals (Cd,Cu, Ni,Pb, Zn) by chemically-reinforced biomass of marine algae

Particles of two different sizes (0·105–0·295 mm and 0·84–1.00 mm diameter) of two marine algae, Sargassum fluitans and Ascophyllum nodosum, were crosslinked with formaldehyde (FA), glutaraldehyde (GA) or embedded in polyethylene imine (PEI), followed by glutaraldehyde crosslinking. They were used for equilibrium sorption uptake studies with cadmium, copper, nickel, lead and zinc. The metal uptake by larger particles (0·84–1·00 mm) was higher than that by smaller particles (0·105–0·295 mm). The order of adsorption for S. fluitans biomass particles was Pb > Cd > Cu > Ni > Zn, for A. nodosum copper and cadmium change places. Uptakes of metals range from q_max = 378 mg Pb g^?1 for S. fluitans (FA, big particles), to q_max = 89 mg Zn g^?1 for S. fluitans (FA, small particles) as the best sorption performance for each metal. Generally, S. fluitans is a better sorbent material for a given metal, size and modification, although there were several exceptions in which metal sorption by A. nodosum was higher. The metal uptake for different chemical modifications showed the order GA > FA > PEI. A comparison of different sorption models revealed that the Langmuir sorption model fitted the experimental data best.     

Sorption characteristics of heavy metal ions by a natural zeolite

Zeolites have been shown to be effective adsorbents for the removal of heavy metals from aqueous solutions. A natural material from Cuba, containing zeolite, has been used for the removal of several metal ions, namely Cu²⁺, Zn²⁺, and Ni²⁺, to evaluate its potential use as a low‐cost adsorbent. Batch experiments have been conducted to evaluate the process kinetics and the removal equilibrium at different pH values, metal and zeolite concentrations. Pseudo‐second order kinetics and Freundlich equilibrium parameters have been obtained. Results suggested that this natural zeolite has a high potential for heavy metal retention. The selectivity of the studied metals was determined as Cu²⁺ ? Zn²⁺ > Ni²⁺, related to the first hydrolysis equilibrium constant. The metal removal efficacy was strongly dependent on pH, and to a lesser extent on metal/zeolite ratio. Copyright © 2005 Society of Chemical Industry     

厌氧氨氧化生物脱氮研究进展

1994年,荷兰学者首先在一个反硝化流化床中发现了厌氧氨氧化（ANAMMOX）现象,后来的研究证明这是一种新型生物脱氮途径.由于ANAMMOX能同时去除氨氮和亚硝酸盐氮,且费用低,近10年来已成为生物脱氮新技术研究的热点.本文综述了ANAMMOX的反应机理,ANAMMOX菌的基本生理生化特征,国内外学者成功启动ANAMMOX反应过程的多种反应器,基于ANAMMOX原理开发的OLAND、SHARON-ANAMMOX和CANON工艺,并简要报道了作者近期以垃圾填埋场渗滤液处理的硝化活性污泥为驯化微生物,成功地在56 d里启动了ANAMMOX反应过程的结果.     

厌氧氨氧化过程的研究进展

氨的厌氧氧化（Anammox)是近年来微生物学领域的一个新发现，它是指在厌氧条件下，通过特定的兼性和专性厌氧的自养细菌的作用。将NH4^ -N和NO2^--N反应转化为N2的过程，国外已对此进行了广泛研究并开始应用于废水生物处理中。Anammox工艺与现有工艺相比有明显的优越性。回顾了近年来国际上在厌氧氨氧化方面的研究和应用进展。概要介绍了可能的厌氧氨氧化反应机理。参与的细菌和可行的工艺。     

强化混凝沉淀去除水中三种二价重金属离子的试验研究

本研究模拟水源水分别受到5倍超标的铅、镍、镉3种重金属的污染,考察了常规混凝工艺的去除效果,温度对于混凝-沉淀工艺去除3种重金属污染的效果影响,并本文重点研究了pH值对于去除3种重金属效果的影响.结果表明,常规混凝沉淀工艺无法将该污染水处理达标,混凝剂聚合氯化铝(PAC)投量为90mg·L-1时,可以取得相对较好的混凝...     

Enhancement of heavy metal ion adsorption using electrospun polyacrylonitrile nanofibers loaded with ZnO nanoparticles

This article describes the adsorption and tensile behavior of electrospun polyacrylonitrile (PAN) nanofiber mats loaded with different amounts of ZnO [0.5, 1.0, 2.0, and 5.0 wt%] nanoparticles. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transforminfrared (FTIR) spectroscopy, and thermal gravimetric analysis (TGA) were utilized to characterize the resulting composite nanofibers. Microscopic investigations revealed that the increase in surface roughness and diameter of the electrospun PAN nanofibers was due to the addition of ZnO nanoparticles. Adsorption results indicated that the fabricated PAN/ZnO (2.0 wt%) composite nanofiber mats showed the best adsorption performance with 261% and 167% increase in adsorption capacities for Pb(II) and Cd(II) from aqueous solutions, respectively, compared to pristine PAN nanofibers. The adsorption equilibrium was reached within 60 min, and the process could be described using the nonlinear pseudo-second-order kinetic model. The adsorption isotherm study was better represented by the Langmuir model, which suggested a homogeneous distribution of the monolayer adsorptive sites on the surface of the composite nanofibers. Mechanical testing revealed that the decrease in tensile strength and elongation at breakof the PAN/ZnO composite nanofiber mats was due to the formation of some bead defects and agglomerates within the structure of the PAN nanofibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47209.     

厌氧序批式反应器的厌氧氨氧化工艺启动运行

在厌氧序批式反应器中接种好氧硝化污泥,进行了培养厌氧氨氧化污泥的研究。在进水pH值为7.2～7.8,温度为30±1℃的条件下运行142d,成功培养出厌氧氨氧化污泥。反应器内的污泥量(以VSS计)由原来的9.90g/L增加到18.99g/L,水力停留时间为1.20d,总氮容积负荷为0.4318kg/(m·3d)时,总氮去除率最高达到93.3%,平均为80.5%,氨氮和亚硝酸盐氮的去除率最高分别达到93.9%和99.8%,平均去除率分别为81.2%和85.7%,氨氮和亚硝酸盐氮去除的比例为1∶1.387±0.024。对该工艺优化实验研究表明,适宜pH值为7.2～7.8,最适宜温度为35℃;且适度强化反硝化作用有利于提高反应器的脱氮性能。     

有机物对厌氧氨氧化生物脱氮影响研究

以经过处理和未经处理的生活污水中添加碳酸氢铵、亚硝酸钠为试验用水,进行了两阶段对比研究,以期考察有机物对厌氧氨氧化生物脱氮效果的影响。研究结果表明,在平均pH值为8.07,ALK为855～1468mg/L、平均进水NH3-N、NO2--N、COD的质量浓度分别为325.57、301.63、139.35mg/L的条件下,二级串联反应器两阶段的TN去除率分别为78.63%、76.57%,COD去除率分别为64.54%、66.87%。在高氨氮、低碳氮比水质条件下,难降解有机物对厌氧氨氧化细菌活性没有太大影响。同时,扫描电镜观察结果证实,污泥中形成了以厌氧氨氧化球状菌为主,其它杆状菌、丝状菌共存的微生物混培体。此外,厌氧氨氧化菌表面附着的颜色较亮的白色小球,可能是反硝化菌。     

硝酸铵氧化法制备氯化亚铜技术研究

介绍了硝酸铵氧化分解海绵铜生产氯化亚铜的方法。工艺过程：将海绵铜加入硝酸铵和硫酸的混合液中,海绵铜中的铜溶解得到硫酸铜溶液;向硫酸铜溶液中加入亚硫酸铵和氯化铵,亚硫酸铵将硫酸铜还原为硫酸亚铜,氯化铵将硫酸亚铜氯化沉淀为氯化亚铜;氯化亚铜经酸洗、醇洗、烘干得到成品;滤液经蒸发浓缩得到硫酸铵副产品。最佳制备条件：（1）海绵铜溶解过程,反应温度为60 ℃,硫酸浓度为0.2~0.3 mol/L,硝酸铵用量为过量10%~20%;（2）沉淀氯化亚铜过程,亚硫酸铵与硫酸铜的物质的量比为0.6,氯化铵与硫酸铜的物质的量比为1.0~1.1; （3）沉淀氯化亚铜用质量分数为2%的硫酸水溶液洗涤,再用质量分数为95%的乙醇洗涤,再经烘干得到氯化亚铜产品,所得产品质量符合GB/T 27562-2011《工业氯化亚铜》要求。     

厌氧氨氧化脱氮工艺研究进展

厌氧氨氧化（ANAMMOX）新型生物脱氮工艺能同时去除氨和亚硝酸盐,并且因其运行成本低、无二次污染等优点,而具有广阔的应用前景。但其倍增时间过长（11天）,受影响的因素较多等特点使其难以工业化,因此得到了广泛关注。本文综述了厌氧氨氧化工艺应用的研究现状,其单级系统具有投资少、占地小等优点,而两级系统则运行更灵活、稳定;剖析了其温室气体（N2O）排放特性,对厌氧氨氧化过程中可能的N2O代谢途径进行分析并就现有单级系统与两级系统N2O的排放数据进行归纳;讨论了厌氧氨氧化工艺运行的稳定性,就一些对该工艺产生抑制作用的因素进行总结,如重金属、抗生素、酚类等有毒物质;最后对厌氧氨氧化工艺未来研究和应用动态进行了展望,预测该工艺今后在低温环境中的应用以及从单一的氨氮去除到多种污染物去除的可能性。     

原子吸收分光光度法测定中药材中重金属含量

采用火焰法、石墨炉法,样品消解后直接测定中药材丹参、白芍中重金属铜、铅、镉的含量。结果表明：重金属铜在0～0.8μg/mL、铅在0～80μg/L、镉在0～0.8μg/L范围线性关系良好,相关系数分别为0.995 6、0.996 3、0.999 4;丹参、白芍中所含铜、铅、镉均符合《中国药典》规定。本法简单、快速、灵敏,适用于中药材中微量重金属的测定,结果满意。     

标准加入原子吸收法连续测定光亮镀镍液中铜、锌、铬、铅、铁杂质的含量

在相同的光亮镀镍液中分别加入浓度依次递增的铜、锌、铁、铬、铜的标准溶液。用原子吸收光谱法连续测定镀液中铜、锌、铁、铬、铅杂质的含量,优选出最佳的仪器工作条件,讨论了共存元素的干扰及消除。该方法简单,准确度和精密度高,具有使用价值。     

Removal of toxic metals from aqueous mixtures. Part 1: Biosorption

The biosorption of toxic metals from an aqueous mixture containing zinc, copper and nickel, in the presence of calcium and sodium ions (usual co‐existing cations in related systems) has been investigated. Industrial biomass samples of different origin have been examined batchwise as effective sorbents, including bacteria (Streptomyces rimosus), fungi (Penicillium chrysogenum) and yeasts (Saccharomyces carlsbergensis and Saccharomyces cerevisiae). The effect of solution pH was evaluated in the range of 3–11.5. Selectivity was observed, particularly for the removal of copper. The observed removal of metals by the application of biosorption was also compared in laboratory experiments with other more conventional separation techniques (filtration, centrifugation and flotation). © 1999 Society of Chemical Industry     

铜镉渣综合利用研究

利用铜、镉和锌氧化还原电位相差较大的原理,对铜镉渣有价金属进行了分离。结果表明,控制浸出温度为50 ℃、硫酸质量分数为17%、液固体积质量比为4 mL/g、浸出时间为2.5 h时,金属铜可以得到优先分离。采用二段逆向锌还原镉,一段采用连续加锌置换,锌粉加入量为理论量的90%,加锌时间控制在20 min左右,二段置换中锌加入量为理论量的1.2~1.3倍,溶液中99.6%的镉被除去。除镉后溶液除钴后,硫酸锌溶液能够满足电锌要求。     

浏阳七宝山矿区复杂多金属矿综合利用

针对浏阳市七宝山矿区复杂多金属矿的综合利用,文章进行了实验分析、条件研究、尾矿综合利用、铜铅混合浮选及铜铅分离试验、选铜尾矿试验研究、工艺流程的完善、选铅废水回用、废水取代硫酸的研究、流程综合设计、药剂制度的完善和技术路线研究。     

Comparison of filter media,plant communities and microbiology within constructed wetlands treating wastewater containing heavy metals

The aim of this study was to investigate the treatment efficiency of passive vertical‐flow wetland filters containing Phragmites australis and/or Typha latifolia and granular media of different adsorption capacities. A cost–benefit analysis was performed on the characteristics of constructed wetlands. Cheap gravel and sand as well as expensive granular activated carbon, charcoal and Filtralite (light expanded clay) were used as filter media. Different concentrations of lead and copper sulfate were added to polluted urban beck inflow water in order to simulate pre‐treated mine wastewater, landfill leachate or highway runoff. The relationships between growth media, microbial and plant communities as well as the reduction of lead, copper, five‐day biochemical oxygen demand (BOD) in particular, and potentially pathogenic bacteria were investigated. A breakthrough of copper within the first 9 weeks was only recorded for filters containing media with limited adsorption capacities. The breakthrough was independent of the presence of plants. However, after maturation of the biomass, which dominated the schmutzdecke and litter zone, lead and copper concentrations were reduced by 97–99% and BOD by 41–60% in all wetlands. There appears to be no additional benefit in using macrophytes and expensive adsorption media in constructed wetlands to enhance metal reduction during the set‐up period of 5 months. © 2001 Society of Chemical Industry     

厌氧氨氧化影响因素实验研究

研究了水力停留时间(HRT)、温度、pH和进水m(NH_4~+-N)∶m(NO_2~- -N)对厌氧氨氧化脱氮性能的影响.实验结果表明,厌氧氨氧化的最佳HRT、温度、pH、进水m(NH_4~+-N)∶m(NO_2~- -N)分别为12 h、30～35℃、7.02～8.36、0.95～1.2.在最佳反应条件下,当进水TN质量浓度为365.5～432.4 mg/L时,对NH_4~+-N、NO_2~--N、TN的平均去除率分别为96.8%、97.8%、92.4%.     

阳极溶出方波伏安法同时测定竹叶提取物中的铜、铅和镉

在CH3COOH-CH3COONa底液中,用阳极溶出方波伏安法同时测定竹叶提取物中铜、铅、镉3种元素含量,该法的最佳条件为:控制CH3COOH-CH3COONa缓冲溶液的pH=4 5,且c(CH3COONa)=0 12mol/L;选择方波频率为30Hz,电位扫描速度为4mV/s,在-0 8V处富集240s后采用方波伏安法正向扫描至0 15V。当铜、铅、镉金属离子的质量浓度为0 05～30μg/L时,线性关系较好,相关系数分别为0 9985,0 9992和0 9985,加标回收率分别为101 6%,99 0%和101 0%。     

杂环三氮烯类试剂的合成及其应用

综述了近年来报道的杂环三氮烯类试剂的合成及应用情况。介绍了部分新试剂在光度分析中的应用实例，初步探讨了试剂的灵敏度和取代基之间的相互影响以及杂环三氮烯类试剂今后的合成方向。