Exploring Kinetics of Phenol Biodegradation by Cupriavidus taiwanesis 187

Phenol biodegradation in batch systems using Cupriavidus taiwanesis 187 has been experimentally studied. To determine the various parameters of a kinetic model, combinations of rearranged equations have been evaluated using inverse polynomial techniques for parameter estimation. The correlations between lag phase and phase concentration suggest that considering phenol inhibition in kinetic analysis is helpful for characterizing phenol degradation. This study proposes a novel method to determine multiplicity of steady states in continuous stirred tank reactors (CSTRs) in order to identify the most appropriate kinetics to characterize the dynamics of phenol biodegradation.     

模拟煤炭气化废水中苯酚的微生物降解

苯酚是煤炭气化废水中一种典型的有机污染物,其处理受到广泛关注和研究。本文采用连续驯化和平板划线法从焦化废水和气化废水中筛选出两种苯酚高效降解菌株,分别命名为JHFS-1和QHFS-1;通过苯酚溶液的微生物降解实验研究了温度、pH、摇床转速、细菌接种量、Cu²⁺和Mn²⁺等对苯酚降解效果的影响,还考察了模拟煤炭气化产生的煤气洗涤水的微生物净化修复效果。结果发现：经16S rDNA基因测序和微生物学鉴定,两种菌株均为醋酸钙不动杆菌(Acinetobacter calcoaceticus);30℃、pH=6.0、摇床转速120r/min、接种量13%是苯酚的最优降解条件,经24h处理,苯酚降解率可达94.31%;Cu²⁺对JHFS-1降解苯酚有一定的抑制作用,Mn²⁺一定程度上促进JHFS-1对苯酚的降解;微生物对苯酚的降解遵从羟基化途径和羧基化途径;JHFS-1菌可有效降解煤气洗涤水中的有机污染物,其总有机碳(TOC)降解率达58.43%。     

混合菌对精噁唑禾草灵微生物降解的初步研究

以产碱菌属H(Alcaligenes.sp.H)以及其紫外诱变菌Huv(Alcaligenes.sp.Huv)为菌源,研究了这两种混合菌降解精噁唑禾草灵的效果.结果表明,Alcaligenes.sp.H和Alcaligenes.sp.Huv三种不同比例的混合菌降解精噁唑禾草灵的效果明显优于H单菌,其中当H菌和Huv菌比例为1:2.5时,明显优于H和Huv二种单菌对精噁唑禾草灵的降解效果.     

The multiple binding of heavy metals by digested sludge

The multiple interactions of heavy metals with anaerobically digested sludges and with digested sludge that had been washed with EDTA have been examined by equilibrating the sludge solids with solutions containing mixtures of zinc acetate, lead acetate and chromic chloride. This equilibration has been studied at 20°C and Langmuir and Freundlich isotherms were used to describe the metal binding behaviour of the solids. The rates of adsorption were also measured. This showed that while the rate constants were independent of the added metal concentration for untreated sludge, the binding constant for washed sludge was related to the initial metal concentration. A comparison of the adsorption isotherms suggests that the binding of zinc is different from that of lead and chromium.     

壳聚糖及其衍生物对重金属吸附性能的研究

壳聚糖分子中含有大量的氨基和羟基,可以进行多种化学改性,得到相应的衍生物。改性前后的壳聚糖对重金属都具有吸附作用,可以作为重金属离子的富集剂。文章综述了近年来壳聚糖及其衍生物在吸附重金属方面的研究进展,对比了不同产品对重金属的吸附容量和选择性,以及它们所适用的条件。文章指出,进一步开发水溶性和螯合能力优良的壳聚糖衍生物是今后研究的方向。     

串山垅原灌区土壤重金属污染状况研究

通过对贵溪串山垅原灌区土壤重金属Cu、Pb、Zn、Cd、As污染对农作物的危害程度分析,得出Cu是造成农田大幅度减产的主要污染因子,其次是Cd、As.提出修复农田土壤重金属污染势在必行.     

生物炭对矿区土壤重金属有效性及形态的影响

为探索生物炭作为改良剂修复矿区重金属污染土壤的可行性,以玉米秸秆为原料在450℃制备生物炭,采用扫描电镜、能谱分析以及傅里叶变换红外光谱等分析与测试手段对其进行表征。采用室内连续培养的方法,研究在不同培养时间条件下,添加不同施用量（0、1%、3%和5%）的生物炭后,对矿区土壤pH,阳离子交换量（CEC）,土壤重金属Cu、Zn、Pb和Mn有效性以及重金属不同形态变化的影响。结果表明：生物炭能够提高土壤的pH和CEC,且都随着添加量的增加而增加。56d土壤培养后,与对照相比,1%、3%和5%添加水平下pH分别增加了1.14个、1.42个和1.67个单位,土壤CEC分别增加了2.02cmol/kg、3.60cmol/kg和5.39cmol/kg。添加不同含量生物炭后,土壤中有效态重金属均呈现不同程度的降低,而且生物炭添加量越大,降幅也越大。在5%添加水平下,生物炭分别使Cu、Zn、Pb和Mn有效态下降了49.2%、46.2%、72.5%和26.3%。重金属有效态含量与土壤pH、CEC均呈显著负相关关系。添加生物炭后,土壤中重金属的形态发生了变化,由易迁移的弱酸提取态向更加稳定的残渣态转化,且生物炭添加量越大,钝化效果越显著。综上所述,玉米秸秆生物炭的添加提高了矿区重金属复合污染土壤的pH和CEC,促进了重金属复合污染土壤中Cu、Zn、Pb和Mn的弱酸提取态向化学性质稳定的残渣态转化,降低了土壤重金属的有效性,实现了对重金属复合污染土壤的修复。     

河湖沉积物对重金属吸附-解吸的研究概况

吸附-解吸是水环境体系中重金属迁移转化的一个重要过程．本文介绍了水体沉积物对重金属吸附-解吸的反应机理,以及各种环境因子的影响;同时综述了沉积物对重金属吸附模式的研究情况。     

烟气中重金属浓度的在线测量

引言 重金属元素在煤粉和城市固体垃圾燃烧过程中会分解释放出来,经历一系列物理化学变化,一部分挥发的重金属元素将富集在飞灰(尤其是亚微米级细小颗粒)上,随着烟气或炉渣排出,它们在大气中有很长的驻留时间,不为微生物降解,并转化为毒性很大的金属有机化合物,从而对人类健康和环境产生极大的危害.     

粉煤灰对水泥中重金属存在形式的影响

本文对添加不同含量的粉煤灰后,熟料水化过程中重金属元素（Cr、Mn、Cu、Pb、Zn）存在形式及其浸出毒性进行了实验和探讨。随着粉煤灰掺入量由0%提升至10%,水化产物形貌中微细孔增多,重金属元素在C-S-H中富集程度增加,熟料重金属元素浸出毒性呈现不同程度下降趋势,最大下降幅度达到56.1%,主要因为微细孔对重金属有较好的吸附作用,且重金属元素在水化产物周围的富集程度增加,有助于重金属离子以较为稳定的形态固化在水化产物中。     

液氯中重金属元素的限量检测方法

介绍一种液氯中重金属元素的限量检测方法：在弱酸性（pH值为3—4）条件下,使试样中的重金属离子与硫化钠作用,生成棕黑色悬浮物。并以采用该法检测铅标准溶液为例,进行了详细说明。     

CuNiAl复合金属氧化物催化ClO2氧化处理苯酚废水

采用共沉淀法合成CuNiAl类水滑石(CuNiAl-LDHs),将水滑石在600℃下焙烧制备出高分散CuNiAl复合金属氧化物催化剂,用XRD、FTIR和SEM对产品进行表征,并用CuNiAl复合金属氧化物催化ClO2氧化处理苯酚。研究结果表明,类水滑石中Cu、Ni、Al的摩尔比影响类水滑石的晶形结构,当n(Cu)∶n(Ni)∶n(Al)=1∶1∶1,可以得到结晶度高、晶体单一的CuNiAl类水滑石,该水滑石焙烧得到的复合金属氧化物催化ClO2氧化处理苯酚废水,可促进废水中苯酚的深度降解,使COD去除率大大提高。适宜的反应条件是:催化剂投加量为3 g/L,废水pH=7.0,反应时间60 min,反应温度室温,废水COD去除率达到65%左右。     

重金属离子在水泥砂浆中的浸出性研究

采用在生料中掺重金属化学试剂在实验室条件下烧制出的熟料,研究了重金属元素在水泥应用过程中的流向,模拟德国的水槽试验法测试了水泥砂浆中重金属离子Ph、Cd、As和Cr在不同pH值浸出液条件下的长期浸出行为,探讨了酸性条件对重金属浸出的影响。结果表明：Pb、Cd及Cr^3＋均可以稳定固化在砂浆内部,长期浸出固化率可达99．9％以上;酸性条件可以抑制Cr^3＋的浸出,促进Cr^6＋的浸出,对Pb、Cd、As的浸出影响较小。     

Removal of heavy metals in a flow‐through vertical microbial electrolysis cell

This work describes laboratory experiments aimed at evaluating the feasibility of removing heavy metals from metal‐contaminated water in flow‐through microbial electrolysis cells (MECs) with peat moss as a source of organic carbon. MECs were assembled in upflow glass columns containing granular activated carbon (GAC) bioelectrodes preceded by a layer of peat moss. The MECs were fed with metal‐contaminated surface water collected at a firing range. At hydraulic retention times (HRT) of 4–6 days, up to 99 % removal of Pb, Zn, Cu, and Fe was observed. The removal efficiency of Zn and Cu declined at an HRT of 1.7 days, while effluent Pb concentration remained below the detection limit for all of the HRTs tested. Metal extraction from MEC compartments showed an accumulation of metals in both the peat moss layer and the GAC cathode, i.e., the removal was achieved by a combination of anaerobic and bioelectrochemical pathways of metal reduction. A proliferation of sulphate reducing bacteria in the peat moss layer and electroactive species in GAC electrodes was confirmed by biomolecular analysis. The proposed flow‐through system, which combines sulphate‐reducing and electroactive microbial activities to achieve near‐complete metal removal, can be used for removing a broad range of heavy metals from contaminated water in a low‐cost passive flow treatment system.     

分子筛对重金属废水吸附性能的实验研究

为验证分子筛对重金属废水的处理效果,以实际含锰废水为研究对象,采用13X分子筛,通过实验研究了吸附材料用量、吸附时间、搅拌转速和溶液pH对Ca²⁺、Mn²⁺、Mg²⁺吸附效果的影响。结果表明：吸附材料用量增加对Mn²⁺、Mg²⁺的吸附影响较大;随着吸附时间增长,各金属离子去除率增加;适当的转速有利于金属离子的吸附,但各金属离子对应的最佳转速各不相同;pH提高,能够促进分子筛对金属离子的吸附。13X分子筛对金属离子的吸附机理为离子交换吸附和表面吸附。研究表明,13X分子筛在处理低浓度含锰重金属废水方面表现出良好的应用前景。     

硫酸盐生物还原和重金属的去除

重金属废水的排放带来了长期的环境污染。利用硫酸盐还原菌生物还原硫酸盐的过程中同时可将重金属化学沉淀为难溶金属硫化物而去除。文章对硫酸盐生物还原法去除重金属的原理、特点、影响因素和研究现状进行了阐述．从而说明该法去除重金属是可行和有效的,它对于处理重金属废水具有现实意义。     

炼油废催化剂中分离有害重金属工艺条件研究

以炼油废催化剂为原料,用硫酸、盐酸、硝酸3种不同的酸处理含高镍等重金属元素的炼油废催化剂。采用火焰原子吸收光谱法测定其中镍、汞、铅、铬、镉5种重金属的含量,探讨炼油废催化剂中分离有害重金属的最佳工艺条件。结果表明：在煅烧温度为400 ℃,煅烧时间为3 h,质量分数为10%的硫酸,液固体积比为5∶1,浸出时间为5 h的条件下,镍、汞、铅、铬、镉的浸出效果最好。     

改性膨润土吸附重金属离子的研究与应用进展

膨润土具有很强的吸附能力,通过对膨润土进行改性,可提高其对重金属离子的去除能力.国内外学者对改性膨润土用于含重金属离子污水的处理进行了广泛的研究.概述了膨润土改性制备方法和表征手段,讨论了影响改性膨润土吸附重金属离子的主要因素.对近年来国内外改性膨润土吸附水体中铬、镉、汞、铅、镍等重金属离子的应用研究进行了综述,并指出了改性膨润土用于重金属废水处理存在的问题和今后的研究方向.     

衣藻对重金属生物吸附的实验研究

以衣藻为生物吸附材料,研究了它对重金属钴、铜、锌的生物吸附,并用Freundlich等温吸附方程对实验数据进行处理。结果表明衣藻对这三种金属吸附能力大小顺序为锌钴铜;农藻对重金属的吸附能力很强,可用衣藻来处理含重金属的废水。     

Ozonation of 1,3,6‐naphthalenetrisulfonic acid in presence of heavy metals

A study was conducted of the mechanisms by which heavy metals, commonly present in industrial effluents, increase the purification effectiveness of ozone in the removal of organic contaminants of low biodegradability. For this purpose, the ozonation of 1,3,6‐naphthalenetrisulfonic acid (NTS) in the presence of Ni(II), Fe(II), Mn(II), Zn(II), Sr(II), Cr(III), Cd(II), Hg(II), and Cu(II) was examined. The presence of small amounts of Mn(II), Fe(II), Ni(II), Zn(II), and Cr(III) was observed in the system, increasing the degradation rate of the NTS and transforming the dissolved organic matter into CO₂. The mineralization of the organic matter was highly favored, especially in the first minutes of treatment. The results obtained appear to indicate that the activity of the metals in the NTS ozonation process is related to their reduction potential. Thus, metals susceptible to oxidation by ozone are potential promoters of NTS ozonation. The presence of Fe(II) or Mn(II) during NTS ozonation increased its degradation rate by 79% and 72% respectively. Moreover, the reaction kinetics of metal oxidation with ozone controls the increase in the purification effectiveness of these systems. The presence of radical scavengers (tert‐butanol or bicarbonate) in the medium during the promoted ozonation of NTS showed a negative effect on this process, and the NTS degradation rate decreased with an increasing concentration of these inhibitors in the system. These results confirm that the degradation of NTS by ozone in the presence of heavy metals occurs by a radical mechanism. O₃/Zn(II) and O₃/Fe(II) systems were applied to the decontamination of urban waste waters. The presence of Zn(II) or Fe(II) during the ozonation produced a reduction during the first 5 min of treatment of 20% or 44%, respectively, in the concentration of dissolved organic matter present in the system. These results show that ozonation in the presence of heavy metals is a highly promising system for the purification of waste waters and industrial effluents. Copyright © 2004 Society of Chemical Industry