废水产氢产酸／同型产乙酸耦合产酸条件优化

为了更好地发挥产氢产酸／同型产乙酸耦合系统在废水厌氧发酵生产乙酸方面的优势,有必要寻找一种简单有效的方法以获得该系统产酸的优化条件。利用经过加热处理并活化的厌氧污泥作种泥,以模拟废水中的葡萄糖为底物,针对发酵时间、底物浓度、种泥浓度、初始pH进行4因素10水平均匀设计实验,得到了乙酸生产指标与产酸条件之间关系的回归方程;也得到了以高乙酸产量为主要目标导向同时兼顾高乙酸产率和高乙酸生产强度目标的优化条件;优化条件实验乙酸浓度比均匀设计中最高乙酸浓度提高20％左右。研究表明,将均匀设计应用于废水产氢产酸／同型产乙酸耦合产酸条件优化,可以避免盲目性,迅速获得满意结果。     

高效吸收氧化法处理炼油工业恶臭气体研究

以碳酸钠溶液为吸收液,对苯二酚为催化荆,研究了对炼油企业硫化氢恶臭气体的吸收氧化效果,考察了吸收氧化的影响因素、再生方法及再生效果。结果表明：高效氧化吸收法处理硫化氢恶臭气体效果很好,吸收液可循环使用。     

Combination e ect of pH and acetate on enzymatic cellulose hydrolysis

The productivity and e ciency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate influence the enzymatic hydrolysis of cellulose. The e ects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5–8, and acetate concentrations (0–60 mmol/L). A batch kinetic model for enzymatic cellulose hydrolysis was constructed from experimental data and performed. The base hypothesis was as follows: the rates of enzymatic cellulose hydrolysis rely on pH and acetate concentration. The results showed that the suitable pH range for cellulase production and cellulose hydrolysis (represents e ciency of cellulase) was 2.6–7.5, and 5.3–8.3, respectively. Moreover, acetate in the culture medium had an e ect on cellulase production (KI = 49.50 mmol/L, n = 1.7) less than cellulose hydrolysis (KI = 37.85 mmol/L, n = 2.0). The results indicated that both the pH of suspension and acidogenic products influence the enzymatic hydrolysis of cellulose in an anaerobic environment. To enhance the cellulose hydrolysis rate, the accumulated acetate concentration should be lower than 25 mmol/L, and pH should be maintained at 7.     

土壤悬浮液中五氯酚钠（PCP-Na）的分析方法研究

探索了利用紫外分光光度法测定土壤悬浮液中五氯酚钠的方法。采用紫外可见分光光度计,选定在波长255．6nm处测定土壤悬浮液中五氯酚钠的含量,所得线性回归方程为Y=0．0287X＋0．0022,相关系数r=0．9999,检测限为0．016mg／L,加标回收率为93．357％～95．907％,实验结果表明此法简单、快速,准确性较高。     

HACCP原理在某醋酸装置职业病防控中的应用

目的运用危害分析与关键控制点原理对某新建醋酸装置进行职业病危害控制效果评价,探讨HACCP原理应用于建设项目职业病危害控制效果评价的科学性和实用性。方法通过对某醋酸装置的工程分析和职业卫生调查,识别各种职业病危害因素;并依据职业病危害因素检测和健康检查结果,分析其危害程度。运用HACCP原理,找出职业病危害控制的关键控制点,提出预防控制技术,并验证其效果。结果检测结果显示醋酸充装站、醋酸泵、醋酸精馏塔采样口醋酸浓度超标,醋酸外操岗位8h等效连续A声级超过85dB(A)。结论 HACCP可以运用到化工企业职业病危害防控中,为预防、控制和监督工业企业职业病危害提供科学依据。     

乙酸铜对银鲳幼鱼急性毒性及抗氧化酶活性的影响

为评价乙酸铜对银鲳的安全性及毒性效应,采用静水急性暴露实验,研究了8个乙酸铜浓度梯度(0、0.150、0.206、0.282、0.387、0.531、0.729、1.00 mg·L~(-1))对银鲳幼鱼的急性毒性,以肝脏和鳃组织的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化酶(GSH—PX)以及谷胱甘肽巯基转移酶(GST)活性为指标研究乙酸铜对银鲳幼鱼的毒理作用,并进行安全评价。结果表明,高浓度乙酸铜会对银鲳幼鱼产生了较大的毒性,48 h和96 h-LC_(50)分别为0.898 mg·L~(-1)、0.264 mg·L~(-1),安全质量浓度为0.026 mg·L~(-1);不同浓度乙酸铜胁迫下银鲳幼鱼组织中的SOD、CAT、GSH-PX和GST活性均表现为低浓度被诱导而高浓度受抑制的规律,与乙酸铜浓度呈抛物线型剂量效应关系,此外,肝脏中4种抗氧化酶活性普遍高于鳃组织。研究发现,乙酸铜胁迫对抗氧化酶的影响,可以反映银鲳幼鱼机体的受损状况,其中SOD可较灵敏地指示早期低浓度的铜污染。     

醋酸铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响

为了研究环境中常见重金属污染物铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响及其可能的分子机制,使用不同浓度醋酸铅暴露大鼠胰岛瘤细胞INS-1,利用磺酰罗丹明B(sulforhodamine B,SRB)法检测细胞存活率;Western blot法检测不同浓度醋酸铅对细胞中自噬与凋亡标志蛋白及哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路标志分子表达的影响;利用活性氧(reactive oxygen species,ROS)试剂盒检测细胞内ROS水平;用ROS清除剂N-乙酰-L-半胱氨酸(N-acetylcysteine,NAC)预处理细胞,检测醋酸铅引起的细胞自噬与凋亡是否受到影响。使用统计学软件SPSS 17.0对数据进行统计学分析后,与对照组相比,醋酸铅导致INS-1细胞的存活率下降(p0.05),且呈时间-剂量依赖性;随醋酸铅浓度增大,自噬和凋亡标志蛋白表达增加,mTOR信号途径标志分子没有明显变化;NAC预处理后醋酸铅引起的细胞自噬和凋亡减少。实验结果表明,醋酸铅可通过mTOR-非依赖途径诱导INS-1细胞的自噬与凋亡,其可能机制为刺激细胞内ROS的产生。     

硫酸盐还原菌促进市政污泥厌氧发酵产乙酸

添加各浓度钼酸盐考察不同抑制水平下硫酸盐还原菌(SRB)对市政污泥发酵产酸的作用. 结果表明:在有硫酸盐存在时,未抑制SRB体系中ρ(乙酸)占ρ(总VFAs)的比例可达83%,无丙酸、丁酸积累;而在SRB高抑制水平体系中,ρ(乙酸)只占约40%. 随后以未添加硫酸盐体系为对照,研究了硫酸盐投加方式及在发酵中后期抑制SRB对产物中挥发性脂肪酸(VFAs)成分及其浓度的影响;同时,通过对dsrA酶的编码基因含量定量分析发现,随着硫酸盐的加入,SRB数量速增,产物中丙酸、丁酸先后转化为乙酸,且ρ(乙酸)占ρ(总VFAs)的比例可达90%以上. 添加SRB可作为实现污泥发酵定向累积乙酸的调控手段.      

Toxic effect of sodium perfluorononyloxy-benzenesulfonate on Pseudomonas stutzeri in aerobic denitrification,cell structure and gene expression

• OBS inhibited the growth of P. stutzeri and destroyed its structure. • OBS was toxic to the aerobic denitrification process of P. stutzeri. • OBS induced the production of ROS in P. stutzeri. • OBS affected the expression of key genes involved in denitrification and SOD. The toxicities of sodium perfluorononyloxy-benzenesulfonate (OBS) to animals and plants are similar to those of perfluorooctane sulfonate. However, the mechanism of its toxicity to aerobic denitrifying bacteria is still unclear. In the present study, the ecotoxicity of OBS on an aerobic denitrifying strain, Pseudomonas stutzeri, was evaluated. The results showed that a dosage of OBS clearly affected the growth and aerobic denitrification of P. stutzeri. When compared with an unamended control, the degradation efficiency of the total nitrogen decreased by 30.13% during exposure to 200 mg/L of OBS, and the complete degradation time of nitrate-nitrogen was delayed by 4 h. The lactate dehydrogenase and superoxide dismutase produced by the bacteria increased with the concentration of OBS, and reactive oxygen species were also detected by confocal laser scanning microscope imaging. Transmission electron microscope imaging revealed chromosome deformation of the cells and damage to cell content; moreover, outer membrane vesicles were secreted from the bacteria, which was the important detoxification mechanism of P. stutzeri to OBS. Expression of the genes involved in aerobic nitrification and oxidative stress were also changed under OBS stress, which further confirmed the toxicity of OBS to P. stutzeri. This study reveals the environmental exposure risk of OBS from the perspective of microorganisms.     

富磷污泥厌氧发酵过程中乙酸浓度对磷释放的影响

以强化生物除磷(EBPR)污泥为研究对象,考察了不同初始乙酸浓度条件下富磷污泥厌氧发酵过程中磷及相关指标的变化,并探讨释磷机制.结果表明:初始乙酸浓度对污泥最大释磷量影响不大,(73.1±2.2)%的污泥总磷量(TP)以磷酸盐的形式释放到液相中,其主要来自聚磷的分解.聚磷的分解途径包括:1)聚磷菌(PAOs)通过吸收乙酸贮存聚β-羟基烷酸酯(PHA)的厌氧生物释磷机制释放磷酸盐;2)PAOs的维持作用导致的聚磷直接分解过程.当初始乙酸浓度不充足时,生物释磷过程受限制,聚磷以相对较慢的速率直接分解;随着乙酸浓度的增大,生物释磷速率增快,同时随之增加的PHA含量能促进污泥的水解酸化.上清液中PO43--P和Mg2+浓度在达到最大值后出现了下降的现象,其可能形成鸟粪石等沉淀.根据试验数据,本文提出了从富磷污泥中回收磷的策略,即可在厌氧消化开始前向污泥中投加一定量碳源,并在发酵24h内分离上清液进行磷回收,这样不仅可以快速大量地从上清液中回收磷并减少沉淀引起的管道堵塞等问题,还可消除高浓度磷酸盐对厌氧消化的影响.