改性油页岩灰渣对水中DNBP吸附去除效果

采用PDMDAAC改性方法对油页岩灰渣进行改性,确定最佳改性方案,并研究了环境因素对改性油页岩灰渣吸附DNBP的影响。实验研究结果表明,油页岩灰渣经20 g/L 的PDMDAAC处理时,对DNBP的吸附能力最强。在吸附温度为30℃,初始溶液pH值为4的条件下,0.3 g 的改性油页岩灰渣对30.0 mg/L DNBP溶液50 mL,吸附120 min时,其吸附率达到94.48%以上。在实验条件下,改性油页岩灰渣对DNBP的吸附符合Langmuir和Freundlich等温吸附方程,相关系数分别为0.9985和0.9776,其对DNBP的理论饱和吸附量达到6.196 mg/g。改性油页岩灰渣对DNBP的吸附主要归因于离子交换和表面吸附作用。     

CS-Fe和CS-Fe/Ni的制备及其用于去除钴离子

以氯化铁为铁源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原法制备壳聚糖稳定纳米铁（CS-Fe）;并以氯化铁为铁源,硫酸镍为镍源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原共沉淀法制备壳聚糖稳定纳米铁镍（CS-Fe/Ni）。通过SEM、EDS、XRD、FT-IR等表征手段,对所制备的CS-Fe和CS-Fe/Ni的形貌及微观结构进行表征,并以Co²⁺为目标去除物评价CS-Fe和CS-Fe/Ni的反应活性。初步研究表明,制成的CS-Fe含有单质纳米铁,颗粒多数以30~90 nm球形颗粒为主;而CS-Fe/Ni材料中含有纳米铁镍,颗粒多数以30~60 nm球形颗粒为主;在相同的实验条件下,反应60 min,CS-Fe/Ni对Co²⁺的去除率高达100%,但是CS-Fe仅为88%,即CS-Fe/Ni对Co²⁺的去除率比CS-Fe高。     

餐厨垃圾和绿化废弃物混合堆肥的试用

以餐厨垃圾和绿化废弃物堆肥作为种植基质,研究了其不同堆肥比例对黑麦草(Lolium perenne L.)生长的影响。结果表明,将不同基质组分别施用后,黑麦草各项生长指标(植株高度、盖度、地上和地下生物量(干重))均良好,其中2#基质(80%土壤+20%堆肥)施用效果优于1#(90%土壤+10%堆肥)和3#(70%土壤+30%堆肥)基质。对比不同堆肥对黑麦草生长的影响发现,(80%+20%)堆肥6处理的黑麦草地上和地下生物量最大,分别约为40 g和28 g,第三茬草地上生物量(干重)与对照组相比增幅为164.3%,盖度达到了98%。本研究确定了堆肥和土壤的最佳配比以及最佳堆肥类型,不但可以解决其资源化再利用的问题,而且植物生长良好,表明该技术在城市绿化中具有一定的应用前景。     

Study on preparation method of <Emphasis Type="Italic">Zanthoxylum bungeanum</Emphasis> seeds kernel oil with zero trans-fatty acids

The seed of Zanthoxylum bungeanum (Z. bungeanum) is a by-product of pepper production and rich in unsaturated fatty acid, cellulose, and protein. The seed oil obtained from traditional producing process by squeezing or extracting would be bad quality and could not be used as edible oil. In this paper, a new preparation method of Z. bungeanum seed kernel oil (ZSKO) was developed by comparing the advantages and disadvantages of alkali saponification-cold squeezing, alkali saponification-solvent extraction, and alkali saponification-supercritical fluid extraction with carbon dioxide (SFE-CO₂). The results showed that the alkali saponification-cold squeezing could be the optimal preparation method of ZSKO, which contained the following steps: Z. bungeanum seed was pretreated by alkali saponification under the conditions of adding 10 %NaOH (w/w), solution temperature was 80 °C, and saponification reaction time was 45 min, and pretreated seed was separated by filtering, water washing, and overnight drying at 50 °C, then repeated squeezing was taken until no oil generated at 60 °C with 15 % moisture content, and ZSKO was attained finally using centrifuge. The produced ZSKO contained more than 90 % unsaturated fatty acids and no trans-fatty acids and be testified as a good edible oil with low-value level of acid and peroxide. It was demonstrated that the alkali saponification-cold squeezing process could be scaled up and applied to industrialized production of ZSKO.     

Enhanced excess sludge hydrolysis and acidification in an activated sludge side-stream reactor process with single-stage sludge alkaline treatment: a pilot scale study

A pilot-scale side-stream reactor process with single-stage sludge alkaline treatment was employed to systematically investigate characteristics of excess sludge hydrolysis and acidification with alkaline treatment and evaluate feasibility of recovering a carbon source (C-source) from excess sludge to enhance nutrient removal at ambient temperature. The resulting C-source and volatile fatty acid specific yields reached 349.19 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS) d⁻¹ and 121.3 mg COD/g VSS d⁻¹, respectively, the process had excellent C-source recovery potential. The propionic-to-acetic acid ratio of the recovered C-source was 3.0 times that in the influent, which beneficially enhanced biological phosphorus removal. Large populations and varieties of hydrolytic acid producing bacteria cooperated with alkaline treatment to accelerate sludge hydrolysis and acidification. Physicochemical characteristics indicated that recovered C-source was derived primarily from extracellular polymeric substances hydrolysis rather than from cells disruption during alkaline treatment. This study showed that excess sludge as carbon source was successfully recycled by alkaline treatment in the process.

     

A comparative study of metal pollution and potential eco-risk in the sediment of Chaohu Lake (China) based on total concentration and chemical speciation

Total and extractable concentrations of Cu, Pb, and Zn were determined in surface sediments of west Chaohu Lake (China) by HCl-HNO₃-HF-HClO₄ digestion and an optimized BCR sequential extraction procedure, respectively. The metal pollution was evaluated by the enrichment factor approach, and the potential eco-risk was evaluated by the sediment quality guideline (SQG) and risk assessment code (RAC) assessments. The results indicated that both total and extractable metal concentrations were highly variable and were affected by sediment properties, even though the sediments were predominantly composed of <63-μm particles (>89 %). Enrichment factors of the metals based on the total and extractable concentrations all showed higher values in the northern lake area and decreasing values towards the south. This distribution indicated an input of anthropogenic metals via the Nanfei River. Anthropogenic Cu, Pb, and Zn in surface sediments showed comparable values for each metal based on the total and extractable concentrations, suggesting that anthropogenic Cu, Pb, and Zn resided predominantly in the extractable fractions. Sediment Cu had low eco-risk, and Pb and Zn had medium eco-risk by the SQG assessment, whereas the eco-risk rankings of Cu, Pb, and Zn were medium, low, and low–high, respectively, by the RAC assessment. Referencing to the labile (dilute acid soluble) metal concentrations, we deduced that the eco-risk of Cu may be largely overestimated by the RAC assessment, and the eco-risk of Pb may be largely overestimated by the SQG assessment. Overall, sediments Cu and Pb may pose low eco-risk, and Zn may pose low–high eco-risk.     

Concentration and composition variations of metals in the outdoor PM10 of elementary schools during river dust episodes

Aeolian river dust can seriously affect the air quality in central Taiwan. The main purpose of this study was to assess the concentration variations of PM₁₀ and metals at different elementary schools during river dust episodes. River dust samples were taken from eight sites in the main bare soil areas of the Choshui River. PM₁₀ aerosols from four elementary schools in Yulin County were collected by means of high-volume samplers. Fifteen elements (Fe, Al, Ca, Mg, Mn, Zn, Ti, Ni, V, Cr, As, Pb, Cu, Co, and Cd) in the river dust and PM₁₀ were analyzed in this study. The coefficients of divergence (CDs) were obtained by comparing the metal compositions in PM₁₀ aerosols at the four schools on the sampling days with the mean metal contents in the river soil samples as reference. The CD values showed that metal compositions in the aerosols at high-exposure sites during river dust episodes were similar to those compositions in the river dust. The concentrations of PM₁₀ at the high-exposure schools during river dust episodes were much higher than those during non-river-dust episodes. This study also indicated that at the high-exposure sites, both the PM₁₀ and metal concentrations were higher than at the low-exposure and control sites, not only during the river dust episodes, but also after the river dust episodes. The concentrations of toxic metals (Ni, Cr, As, and Cd) at the high-exposure sites were about 11.3 times higher during the river dust episodes (189 ng/m³) than during non-river-dust episodes (16.7 ng/m³) and about 8.9 times higher during the same periods at the control site (21.3 ng/m³).     

Dietary antioxidants (selenium and N-acetylcysteine) modulate paraoxonase 1 (PON1) in PCB 126-exposed rats

Environmental pollutants polychlorinated biphenyls (PCBs), especially dioxin-like PCBs, cause oxidative stress and associated toxic effects, including cancer and possibly atherosclerosis. We previously reported that PCB 126, the most potent dioxin-like PCB congener, not only decreases antioxidants such as hepatic selenium (Se), Se-dependent glutathione peroxidase, and glutathione (GSH) but also increases levels of the antiatherosclerosis enzyme paraoxonase 1 (PON1) in liver and serum. To probe the interconnection of these three antioxidant systems, Se, GSH, and PON1, we examined the influence of varying levels of dietary Se and N-acetylcysteine (NAC), a scavenger of reactive oxygen species (ROS) and precursor for GSH synthesis, on PON1 in the absence and presence of PCB 126 exposure. Male Sprague–Dawley rats, fed diets with differing Se levels (0.02, 0.2, or 2 ppm) or NAC (1 %), were treated with a single intraperitoneal injection of corn oil or various doses of PCB 126 and euthanized 2 weeks later. PCB 126 significantly increased liver PON1 mRNA, protein level and activity, and serum PON1 activity in all dietary groups but did not consistently increase thiobarbituric acid levels (thiobarbituric acid reactive substances, TBARS), an indicator of lipid oxidation and oxidative stress, in liver or serum. Inadequate (high or low) dietary Se decreased baseline and PCB 126-induced aryl hydrocarbon receptor (AhR) expression but further increased PCB 126-induced cytochrome P450 1A1 (CYP1A1) expression, the enzyme believed to be the cause for PCB 126-induced oxidative stress. In addition, a significant inverse relationship was observed not only between dietary Se levels and PON1 mRNA and PON1 activity but also with TBARS levels in the liver, suggesting significant antioxidant protection from dietary Se. NAC lowered serum baseline TBARS levels in controls and increased serum PON1 activity but lowered liver PON1 activities in animals treated with 1 μmol/kg PCB 126, suggesting antioxidant activity by NAC primarily in serum. These results also show an unexpected predominantly inverse relationship between Se or NAC and PON1 during control and PCB 126 exposure conditions. These interactions should be further explored in the development of dietary protection regimens.     

温度对复合厌氧折流板膜生物反应器处理生活污水效能的影响简

将新型CAMBR反应器（厌氧折流板反应器（ABR）与膜生物反应器（MBR）优化组合）用于处理生活污水,研究温度对该反应器处理效能的影响。实验水力停留时间7.5 h,混合液回流比设置为200%,pH值为6.5~8.5,溶解氧3 mg/L左右。控制3个温度梯度：高温（32~37℃）,中温（20~25℃）,低温（5~10℃）,每个温度运行35 d。结果表明,在高温条件下,系统出水COD、NH₄⁺-N、TN和TP平均浓度分别为25、0.5、12.5和0.7 mg/L。在中温条件下,系统出水COD、NH₄⁺-N、TN和TP浓度分别30、1.2、12.5和0.4 mg/L。在低温条件下,COD和TP分别经过15 d和20 d调整适应,出水可恢复至35 mg/L和1 mg/L。由于低温（10℃以下）对硝化细菌产生强烈抑制,出水NH₄⁺-N去除率最终稳定在35%,TN去除率为40%。低温条件下,该反应器应用于污水处理中需注意适当保温,以保证出水水质。     

亚硝态氮对同时产甲烷反硝化工艺处理畜禽粪水的影响

为进一步提高同时产甲烷反硝化反应对畜禽粪水化学需氧量(COD)和氮的去除效率,应用畜禽粪水于接种颗粒污泥的厌氧混合式反应器,进行不同COD与亚硝态氮浓度比值(COD/NO-2-N)对同时产甲烷反硝化反应的影响研究。通过实时监测反应器内COD、凯氏氮(TKN)、辅酶F420、β-葡萄糖苷酶、产气率、pH和氧化还原电位(ORP)等指标得出,COD/NO-2-N为30/1、40/1时,COD去除率、辅酶F420和β-葡萄糖苷酶含量与空白无亚硝态氮的变化规律一致,亚硝态氮几乎未对糖类水解菌及产甲烷菌活性产生抑制作用;而COD/NO-2-N为10/1、20/1时,COD去除率、辅酶F420和β-葡萄糖苷酶含量较低,糖类水解菌及产甲烷菌活性受到抑制。