分层型水源水库溶解性有机物性质及其膜污染特性

利用激发-发射矩阵(EEM)荧光光谱和紫外吸收光谱研究了深水型水源水库热分层期溶解性有机物(DOM)性质及其膜污染特性随水深的变化.结果表明,水体热分层导致DOM质量浓度和性质也表现出分层特征.变温层受光化学降解影响较大,DOM质量浓度较低,同时受藻类等浮游植物分泌的内源有机物影响,DOM芳香度较低,类富里酸有机物(C1组分)和类腐殖酸有机物(C2组分)荧光强度较低,但类色氨酸有机物(C3组分)荧光强度较高;斜温层DOM受径流输入影响较大,DOM质量浓度和芳香度较高,C1和C2组分荧光强度较高.膜污染方面,变温层DOM造成的总污染最大,但可逆性较好,斜温层和等温层DOM造成的总污染较低,但可逆性较差;对超滤过程中不同荧光组分迁移的分析表明,超滤膜对C3组分截留率较高,但反冲洗对被截留的C3组分去除效果较好,而被膜截留的C1和C2组分较难被反冲洗去除.     

SGO/PVDF-g-PSSA复合质子交换膜的制备及抗污染性研究

为更好的提高PVDF-g-PSSA质子交换膜的性能,将磺化氧化石墨烯（SGO）与PVDF-g-PSSA共聚物混合制得SGO/PVDF-g-PSSA复合质子交换膜.用傅里叶变换红外光谱（FTIR）、X射线光电子能谱（XPS）以及X射线测定仪（XRD）证实了GO的成功磺化.对复合膜进行SEM表征并考察了复合膜的主要性能,得到了最佳SGO掺加量.使用耗散型石英晶体微天平（QCM-D）研究了复合膜的抗污染性能.实验结果表明：当SGO添加量为1.0%时,复合膜的含水率达到44.34%,质子传导率为0.085S/cm,综合性能达到最佳.QCM-D实验表明,在纯水和50mmol/L PBS条件下,复合膜表面的BSA吸附量均最低,且|ΔD/ΔF|最大,说明吸附层较为疏松,复合膜具有较好的抗污染性.     

活性污泥中一氧化氮还原酶的提取和测定优化

通过正交实验,研究了超声破碎法和低温高压破碎法提取一氧化氮还原酶（nitric oxide reductase,nor）的活性,分析了超声强度和次数,破碎压力和次数,裂解液的添加量等因素对于胞内可溶性蛋白和核酸（DNA）的释放与提取nor活性的影响.根据活性污泥中酶的催化特性以及其他实验条件,完善了nor催化活性的测定方法.结果表明超声法提取nor的参数应设定为,超声次数为100次,超声强度为500W,裂解液的添加量为0.1mL.低温高压破碎法提取nor的参数应设定为破碎次数为4次,破碎压力为50MPa,裂解液的添加量为0.1mL.低温高压破碎法下的胞内可溶性蛋白和DNA的释放量与nor的最大催化活性要高于超声破碎法.此外,在nor催化活性的测定方法中,nor活性测定终点时间应为15min.     

Bamboo charcoal enhances cellulase and urease activities during chicken manure composting: Roles of the bacterial community and metabolic functions

Microbial enzymes are crucial for material biotransformation during the composting process. In this study, we investigated the effects of adding bamboo charcoal (BC) (i.e., at 5%, 10%, and 20% corresponding to BC5, BC10, and BC20, respectively) on the enzyme activity levels during chicken manure composting. The results showed that BC10 could increase the cellulose and urease activities by 56% and 96%, respectively. The bacterial community structure in BC10 differed from those in the other treatments, and Luteivirga, Lactobacillus, Paenalcaligenes, Ulvibacter, Bacillus, Facklamia, Pelagibacterium, Sporosarcina, Cellvibrio, and Corynebacterium had the most important roles in composting. Compared with other treatments, BC10 significantly enhanced the average rates of degradation of carbohydrates (D-xylose (40%) and α-D-lactose (44%)) and amino acids (L-arginine (16%), L-asparagine (14%), and L-threonine (52%)). We also explored the associations among the bacterial community and their metabolic functions with the changes in the activities of enzymes. Network analysis demonstrated that BC10 altered the co-occurrence patterns of the bacterial communities, where Ulvibacter and class Bacilli were the keystone bacterial taxa with high capacities for degrading carbon source, and they were related to increases in the activities of cellulase and urease, respectively. The results obtained in this study may help to further enhance the efficiency of composting.     

硼酸和磷酸对PMS/Co2+均相催化氧化有机物的影响因素与机制

基于过一硫酸盐（PMS）的高级氧化方法被广泛用于有机污染物的降解.本研究以富电子偶氮染料酸性橙7（AO7）为目标有机物,探究了在硼酸（路易斯酸）和磷酸（布朗斯台德酸）两种不同类型的缓冲液中,PMS/Co²⁺均相催化氧化降解有机物的差异、影响因素及作用机制.PMS/Co²⁺均相催化氧化体系在磷酸盐缓冲液中降解有机物的k值高于其在硼酸盐缓冲液中,而在磷酸盐缓冲液中的前10 s降解率却低于其在硼酸盐缓冲液中.该体系氧化降解有机物在硼酸和磷酸缓冲液中的差异随着缓冲液、PMS浓度、Co²⁺浓度和pH的变化而有所不同.PMS/Co²⁺体系在磷酸盐缓冲液中主要通过SO₄^-·或·OH氧化降解有机物,在硼酸盐缓冲液中,PMS/Co²⁺体系主要通过非自由基途径（¹O₂）降解有机物.该研究将为PMS均相催化中不同类型缓冲液的应用提供参考.     

初始pH值对连续投加铝盐混凝去除小分子有机物的影响机制

以污水厂二级出水中小分子有机物强化混凝去除为目的,提出了连续投加混凝工艺(CDC),并以水杨酸为模型小分子有机物,研究了初始pH值对CDC工艺去除效果的影响以及铝离子与水杨酸的络合特性.结果表明,初始pH值6时CDC工艺的去除率最高,比常规混凝工艺提升了13.8%.但是初始pH值5和7时CDC工艺的提升效果较小.三维荧光结果表明,不同pH值下水杨酸和铝离子的络合特性不同.X射线光电子能谱和电喷雾质谱结果表明,pH值5时CDC工艺前期主要生成1:1络合物Al(OH)(C₇H₄O₃)(H₂O)₂.其络合作用强烈,稳定性较高,难以从水中去除.pH值6时前期主要生成中等聚合铝(如原位Al₁₃),其与水杨酸形成的络合物可以参与到铝离子的生长过程,最终生成表面崎岖形态松散的珊瑚礁状絮体,强化了水杨酸的去除.pH值7时,主要生成不定形氢氧化铝,通过絮体表面吸附小分子有机物.     

Release of Pb adsorbed on graphene oxide surfaces under conditions of Shewanella putrefaciens metabolism

In this study, Pb(II) was used as a target heavy metal pollutant, and the metabolism of Shewanella putrefaciens (S. putrefaciens) was applied to achieve reducing conditions to study the effect of microbial reduction on lead that was preadsorbed on graphene oxide (GO) surfaces. The results showed that GO was transformed to its reduced form (r-GO) by bacteria, and this process induced the release of Pb(II) adsorbed on the GO surfaces. After 72 hr of exposure in an S. putrefaciens system, 5.76% of the total adsorbed Pb(II) was stably dispersed in solution in the form of a Pb(II)-extracellular polymer substance (EPS) complex, while another portion of Pb(II) released from GO-Pb(II) was observed as lead phosphate hydroxide (Pb₁₀(PO₄)₆(OH)₂) precipitates or adsorbed species on the surface of the cell. Additionally, increasing pH induced the stripping of oxidative debris (OD) and elevated the content of dispersible Pb(II) in aqueous solution under the conditions of S. putrefaciens metabolism. These research results provide valuable information regarding the migration of heavy metals adsorbed on GO under reducing conditions due to microbial metabolism.     

Anthraquinone acted as a catalyst for the removal of triphenylmethane dye containing tertiary amino group: Characteristics and mechanism

Herein, we found that anthraquinone (AQ) acted as a catalyst for the rapid and effective removal of triphenylmethane dye containing tertiary amino group (TDAG). Results showed that AQ had an enhanced catalytic reactivity towards the removal of TDAG compared to hydro-quinone, which was further proved and explained using density functional theory (DFT) calculations. AQs could achieve a TDAG removal efficiency and rate of approximately 100% and 0.3583 min⁻¹, respectively, within 20 min. Quenching experiments and electron paramagnetic resonance (EPR) tests indicated that the superoxide radical (O₂^•−) generated through the catalytic reduction of an oxygen molecule (O₂) by AQ contributed to the effective removal of the TDAG. In addition, it was found that the electrophilic attack of the O₂^•− radical on the TDAG was the driving force for the dye degradation process. Decreasing the pH led to protonation of the substituted group of AG, which resulted in formation of an electron deficient center in the TDAG molecule (TDAG-EDC⁺) through delocalization of the π electron. Therefore, the possibility of the electrophilic attack for the dye by the negative O₂^•- radical was significantly enhanced. This study revealed that the H⁺ and the O₂^•− generated by the catalytic reduction of O₂ have synergistic effects that led to a significant increase in the dye removal rate and efficiency, which were higher than those obtained through persulfate oxidation.     

电活化过硫酸盐去除铜绿微囊藻的效果及机理研究

为了开发微藻及藻类有机物的高效去除技术,采用电活化过硫酸盐(EC/PS)体系处理含铜绿微囊藻的水样. 通过藻细胞密度和叶绿素a含量测定以及扫描电镜观察,研究了EC/PS体系的除藻特性及影响因素;采用荧光区域积分法定量分析了除藻过程中胞内有机物(IOM)和胞外有机物(EOM)的变化特征;利用电子顺磁共振波谱仪测定了EC/PS体系中的自由基类别,并分析了EC/PS体系的除藻机理. 结果表明:①在初始藻细胞密度为1.24×107~1.30×107 cells/mL,电压为7 V,初始pH为6,初始PS浓度为4 mmol/L的条件下,当EC/PS体系处理60 min时,藻细胞和叶绿素a的去除率分别达90.80%和98.41%,明显优于单独EC体系和单独PS体系;当EC/PS体系处理10 min时,IOM的总荧光响应值降低了77.39%. 在处理过程中,以腐殖酸类物质为主的胞内有机物会大量释放. ②EC/PS体系中电化学作用对除藻的平均贡献率为54.63%;同时,除藻过程可产生大量的SO₄?·和·OH,且其随处理时间的增加而增加. 研究显示,EC/PS体系能有效去除铜绿微囊藻及藻类有机物,反应体系中的SO₄?·和·OH发挥了重要作用.      

基于改进相互作用矩阵的基坑施工安全风险评价

为解决现有基坑施工风险评价方法过于单一、客观性不足的问题，从勘察设计与监测、支护结构、土方施工、排水与降水、周围环境5个方面选取19个基坑施工安全影响因素；利用引入C-OWA算子的相互作用矩阵对其进行交互耦合分析，考虑各因素的单独作用效果的同时，在削弱专家主观偏好和综合考虑各因素相关性的基础上，研究其协同作用效果；最后用实例验证方法的实用性，结果表明:该项目整体风险偏高，其中排水系统能力、地下水水位和地下管线埋布是影响该基坑施工安全的主要风险因素，需重点防控。