长期冻融循环下固化铅锌镉复合重金属污染土抗剪强度及浸出特征研究

为了评估长期冻融循环后(最长90d (次))固化复合重金属污染土的的抗剪强度及浸出特征,采用水泥、生石灰和粉煤灰按比例混合的复合固化剂固化/稳定化铅锌镉复合重金属污染土进行三轴压缩试验及毒性特征浸出程序试验.结果表明,固化污染土体的内摩擦角仅在冻融循环3次内有明显增加,增加率高达96.3%;粘聚力在冻融循环30次内总体趋势不断下降,之后无显著变化,最终下降率达到54.23%;Pb²⁺、Zn²⁺、Cd²⁺浸出浓度与冻融循环次数呈正比;EC值与冻融循环次数在总体上正相关;长期冻融循环作用后浸出液的pH值降低.并通过扫描电子显微镜,进一步探究长期冻融循环下固化污染土抗剪强度及浸出特征的劣化机理,结果显示在冻融循环后期固化土体内生成了大量的延迟钙矾石,这些延迟钙矾石在形成过程中的膨胀作用是引起抗剪强度损失、重金属浸出浓度升高的主要原因.     

Improving of photocatalytic activity of barium ferrate via bismuth and copper co-doping for degradation of paracetamol under visible light irradiation

Nanosized Ba_{1- x}Bi_xFe_1-xCu_xO₃（12–50 nm） with x values of 0, 0.01, 0.05, and 0.1 system was prepared using the Pechini method. Structural, morphological, surface and optical characterizations were performed for the prepared samples. Cubic phase was the predominant phase for the undoped BaFeO₃ and Bi and Cu co-doped BaFeO₃ samples. Minor phases of monoclinic Ba₂Fe₂O₅, orthorhombic BaFe     

Drivers of microbial beta-diversity in wastewater treatment plants in China

As one of the most well-documented biogeographic patterns, the distance-decay relationship provides insights into the underlying mechanisms driving biodiversity distribution. Although wastewater treatment plants (WWTPs) are well-controlled engineered ecosystems, this pattern has been seen among microbial communities in activated sludge (AS). However, little is known about the relative importance of environmental heterogeneity and dispersal limitation in shaping AS microbial community across China; especially they are related to spatial scale and organism types. Here, we assessed the distance-decay relationship based on different spatial scales and microbial phylogenetic groups by analyzing 132 activated sludge (AS) samples across China comprising 3,379,200 16S rRNA sequences. Our results indicated that the drivers of distance-decay pattern in China were scale-dependent. Microbial biogeographic patterns in WWTPs were mainly driven by dispersal limitation at both local and national scales. In contrast, conductivity, SRT, and pH played dominant roles in shaping AS microbial community compositions at the regional scale. Turnover rates and the drivers of beta-diversity also varied with microorganism populations. Moreover, a quantitative relationship between dispersal limitation ratio and AS microbial turnover rate was generated. Collectively, these results highlighted the importance of considering multiple spatial scales and micro-organism types for understanding microbial biogeography in WWTPs and provided new insights into predicting variations in AS community structure in response to environmental disturbance.     

基于性能参数退化的发动机推进剂加速退化试验建模

目的 针对某火箭弹发动机推进剂加速退化试验数据,建立性能参数退化模型,分别基于最大伸长率和最大抗拉强度等不同参数,计算推进剂的激活能和不同温度下的加速因子。方法 建立基于退化轨迹的性能参数退化模型,对发动机推进剂进行加速退化试验建模,利用最小二乘法计算性能变化参数,利用阿伦尼斯模型计算加速模型的参数,并得到激活能和加速因子。结果 针对推进剂加速试验数据,给出推进剂激活能和不同温度下加速因子的计算方法。采用基于退化轨迹的性能参数退化模型,可有效评估推进剂的寿命。结论 该方法可有效地对推进剂加速试验数据进行建模,给出激活能和加速因子,更能反映推进剂的寿命特征,为寿命评估提供支撑。     

有机生活垃圾多组分联合厌氧降解产甲烷性能研究

为了阐明生活垃圾多组分的混合对其厌氧降解产气性能的影响,通过在中温（37±1）℃下对餐厨类、纸类和园林类垃圾组分进行单独和联合厌氧降解产甲烷实验,研究接种物来源对单组分和多组分物料厌氧降解产甲烷性能的影响,应用修正的Gompertz模型拟合和分析物料产甲烷过程动力学特征,并借鉴和发展评价混合物料联合厌氧降解性能的量化指标方法.试验与模型拟合结果均表明：接种物来源对各组分及其组合的厌氧生物可降解程度无显著影响,但对其降解速率存在明显影响.此外,尽管物料的混合对试验初期物料降解产甲烷速率存在促进作用,但仅有3组分混合试验组在最终累计甲烷产率方面表现出显著的协同促进,在2种接种物条件下,相比于3组分单独降解的甲烷产率分别增长了16%和14%.     

排板式介质阻挡放电等离子体降解苯的研究

考察了自制排板式等离子发生器对不同进气条件(进气浓度、进气流量和进气湿度)下含苯气的降解效果。结果表明,苯降解率随进气浓度和进气流量的提高而降低,但在高进气浓度和高进气流量下,苯降解率仍保持在50%以上。苯降解率在进气湿度约30%时达到最大值,过低和过高的进气湿度都不利于苯的降解。采用多级串联可提高等离子发生器对高进气浓度和高进气流量的适应能力,4级串联较单级时的苯降解率最高可提高39%。排板式等离子体发生器可作为未来等离子体发生器工业化的重点研发对象。     

Preparation of porous semi-IPN temperature-sensitive hydrogel-supported nZVI and its application in the reduction of nitrophenol

Nanoscale zero-valent iron(n ZVI) particles supported on a porous, semi-interpenetrating(semi-IPN), temperature-sensitive composite hydrogel(PNIPAm-PHEMA). n ZVI@PNIPAmPHEMA, was successfully synthesized and characterized by FT-IR, SEM, EDS, XRD and the weighing method. The loading of nZVI was 0.1548 ± 0.0015 g/g and the particle size was30–100 nm. NZVI was uniformly dispersed on the pore walls inside the PNIPAm-PHEMA.Because of the well-dispersed n ZVI, the highly porous structure, and the synergistic effect of PNIPAm-PHEMA, nZVI@PNIPAm-PHEMA showed excellent reductive activity and wide p H applicability. 95% of 4-NP in 100 m L of 400 mg/L 4-NP solution with initial p H 3.0–9.0 could be completely reduced into 4-AP by about 0.0548 g of fresh supported n ZVI at 18–25 °C under stirring(110 r/min) within 45 min reaction time. A greater than 99% 4-NP degradation ratio was obtained when the initial p H was 5.0–9.0. The reduction of 4-NP by nZVI@PNIPAm-PHEMA was in agreement with the pseudo-first-order kinetics model with Kobsvalues of 0.0885–0.101 min-1.NZVI@PNIPAm-PHEMA was able to be recycled, and about 85% degradation ratio of 4-NP was obtained after its sixth reuse cycle. According to the temperature sensitivity of PNIPAmPHEMA, n ZVI@PNIPAm-PHEMA exhibited very good storage stability, and about 88.9%degradation ratio of 4-NP was obtained after its storage for 30 days. The hybrid reducer was highly efficient for the reduction of 2-NP, 3-NP, 2-chloro-4-nitrophenol and 2-chloro-4-nitrophenol. Our results suggest that PNIPAm-PHEMA could be a good potential carrier, with n ZVI@PNIPAm-PHEMA having potential value in the application of reductive degradation of nitrophenol pollutants.     

Comparative study of polyhydroxyalkanoates production from acidified and anaerobically treated brewery wastewater using enriched mixed microbial culture

The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(～2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.     

Enrichment of thermophilic and mesophilic microbial consortia for efficient degradation of corn stalk

Six different environmental samples were applied to enrich microbial consortia for efficient degradation of corn stalk,under the thermophilic and mesophilic conditions.The consortium obtained from anaerobic digested sludge under thermophilic condition(TC-Y)had the highest lignocellulose-degrading activity.The CO_2yield was 246.73 m L/g VS in23 days,meanwhile,the maximum CO_2production rate was 15.48 mL/(CO_2·d),which was28.75%and 52.27%higher than that under mesophilic condition,respectively.The peak value of cellulase activity reached 0.105 U/mL,which was at least 34.61%higher than the other groups.In addition,49.5%of corn stalk was degraded in 20 days,moreover,the degradation ratio of cellulose,hemicellulose and lignin can reach 52.76%,62.45%and42.23%,respectively.Microbial consortium structure analysis indicated that the TC-Y contained the phylum of Gemmatimonadetes,Acidobacteria,Chloroflexi,Planctomycetes,Firmicutes,and Proteobacteria.Furthermore,the Pseudoxanthomonas belonging to GammaProteobacteria might be the key bacterial group for the lignocellulose degradation.These results indicated the capability of degrading un-pretreated corn stalk and the potential for further investigation and application of TC-Y.     

Denitrification and microbial community in MBBR using A. donax as carbon source and biofilm carriers for reverse osmosis concentrate treatment

In this study,raw Arundo donax(A.donax)pieces were applied as carbon source and biofilm carriers for denitrification in a lab-scale moving bed biofilm reactor(MBBR)for the treatment of reverse osmosis concentrate gathered from local wastewater reuse plant.At stable phase(about 60 days),efficient denitrification performance was obtained with73.2%±19.5%NO_(3-)~-N average removal and 8.10±3.45 g N/(m~3·day)NO_(3-)~-N average volumetric removal rate.Mass balance analysis showed that 4.84 g A.donax was required to remove 1 g TN.Quantitative real-time PCR analysis results showed that the copy numbers of 16S r-RNA,narG,nirS,nosZ and anammox gene of carrier biofilm and suspended activated sludge in the declination phase(BF2 and AS2)were lower than those of samples in the stable phase(BF1 and AS1),and relatively higher copy numbers of nirS and nirK genes with lower abundance of narG and nosZ genes were observed.High-throughput sequencing analysis was conducted for BF2 and AS2,and similar dominant phyla and classes with different abundance were obtained.The class Gammaproteobacteria affiliated with the phylum Proteobacteria was the most dominant microbial community in both BF2(52.6%)and AS2(41.7%).The PICRUSt prediction results indicated that 33 predictive specific genes were related to denitrification process,and the relative abundance of 18 predictive specific genes in BF2 were higher than those in AS2.