Adhesive Performance of Sorghum Protein Extracted from Sorghum DDGS and Flour

Distillers dried grains with solubles (DDGS) is the main co-product from grain-based ethanol production. The objective of this research was to compare the adhesive performance of three types of sorghum proteins: acetic acid-extracted sorghum protein from DDGS (PI), aqueous ethanol-extracted sorghum protein from DDGS (PII) and acetic acid-extracted sorghum protein from sorghum flour (PF). Physicochemical properties including amino acid composition, and rheological, thermal and morphological properties also were characterized. Results showed that PI had the best adhesion performance in terms of dry, wet and soak adhesion strength, followed by PF and PII. The wet strength of PI at a concentration of 12% protein assembled at 150 °C was 3.15 MPa, compared to 2.17 MPa and 2.59 MPa for PII and PF, respectively. DSC thermograms indicated that the PF protein isolates contained higher levels of carbohydrates than PI and PII; such non-protein contaminants in the PF isolate could be the reason for its lower adhesion strength than PI. In addition, PI might have more hydrophobic amino acids aligned at the protein-wood interface than PII, which could explain the better water resistance of PI. The optimum sorghum protein concentration and pressing temperature for maximum adhesion strength was 12% and 150 °C. PI had a significantly higher wet strength (3.15 MPa) than unmodified soy protein (1.63 MPa for soy protein). The high percentage of hydrophobic amino acids in PI (57%) was likely a key factor in the increased water resistance of PI compared with soy protein (36% hydrophobic amino acids). These results indicated that sorghum protein has huge potential as an alternative to petroleum-based adhesives.     

电化学法去除水中氯代有机化合物的研究进展

氯代有机化合物难降解、环境危害性极大,对氯代有机化合物的污染进行治理已成为水污染控制的重要课题。介绍了直接电化学氧化法、间接电化学氧化法、直接电化学还原法和间接电化学还原法用于水中氯代有机化合物处理的机理、研究现状;总结了电化学法去除氯代有机化合物的影响因素,同时指出电化学法在实际应用中存在的问题,并展望了氯代有机化合物电化学处理技术的应用前景。     

重碳酸盐碱度对电吸附设备除盐性能影响的研究

为了系统地考察重碳酸盐碱度对电吸附设备除盐性能的影响,利用小型电吸附模块对含有不同重碳酸盐碱度的原水水质进行处理.实验结果表明,随着其含量从170 mg/L增加到400 mg/L,电吸附设备的除盐率明显下降.通过对起始工作电流降低这一变化作理论分析,认为重碳酸盐碱度在电吸附模块内部积存结垢是影响电吸附设备除盐性能的重要原因,并通过实验证实其与钙离子共同作用导致了结垢.     

生物质燃气高温过滤材料的研究

日趋严格的环保要求和某些工艺过程的特殊需要,对生物质燃气中灰尘的数量和粒度提出了更高的要求,即对生物质气化系统中的过滤工艺有了新的要求。针对生物质气化工艺的特点及其灰尘的特性,重点研究了针刺过滤毡和金属多孔材料两类高温过滤材料。通过研究比较,两种材料各有优缺点,针刺过滤毡过滤精度高,运行工况比较稳定,但是过滤气速小,适用温度低,设备比较庞大;金属多孔材料过滤精度相对较低,但是过滤气速和使用温度高,设备相对紧凑。     

PAC/AC吸附对超滤膜去除再生水中有机物影响

研究了粉状活性炭(PAC)和活性焦(AC)吸附对超滤膜(UF)去除再生水中有机物的效能及其对膜污染的影响。结果表明,PAC和AC吸附预处理可有效改善超滤膜出水水质,投量为40 mg/L时,PAC和AC单独吸附对DOC去除率分别为40.2%和32.6%,超滤出水DOC去除率则由直接膜滤时的21.4%提高至47.2%。UF对大于10 kDa的大分子有机物有较好的截留能力,PAC较AC对中小分子有机物的吸附效果更好。三维荧光(3D-EEM)分析显示,原水中溶解性微生物代谢产物和腐殖质类有机物所占比重较大;直接UF对溶解性微生物代谢产物的去除能力较好,投加PAC和AC促进了紫外腐殖酸和类腐殖酸类有机物去除,紫外腐殖酸EEM峰值分别下降51.7%和48.8%,类腐殖酸EEM峰值下降63.0%和59.9%。投加PAC和AC并经0.45 μm膜预过滤可提高超滤膜通量,其在过滤周期内的下降率由直接膜滤时的27.6%分别降至23.5%和24.4%。AC较PAC更为经济,AC-UF可替代PAC-UF作为经济可行的再生水深度净化工艺。     

小波分析在郑州市供暖期PM2.5浓度相关性分析中的应用

为分析供暖期内各种物质与PM2.5的相关性和变化规律,以郑州市供暖期为例,运用Morlet小波分别对PM2.5、PM10、CO、NO2、和SO2的浓度进行分析,并对比各自主周期的小波系数模。结果表明,PM10与PM2.5波动主周期均为33 d,主周期小波系数模差值为0,与PM2.5相关性最高;SO2波动主周期为12 d,与PM2.5相差最大,相关性最低。由于燃煤中各成分含量不同,供暖期SO2与CO、NO2呈中度相关,相关系数依次为0.6045和0.6949;SO2与PM10呈低度相关,相关系数为0.4010。供暖期污染最严重的污染物是PM10和NO2,与非供暖期相比,两者与PM2.5相关系数增量分别为:0.1255和0.2858,相关性提高幅度较大。     

地下水浅埋区某加油站特征污染物空间分布

加油站渗漏污染地下水已经是一个世界性的问题。由于浅埋区加油站储罐与地下水密切接触,更加剧储罐的腐蚀。为揭示加油站渗漏的典型污染物石油烃（TPH）、苯系物（BTEX）、萘和甲基叔丁基醚（MTBE）在该水文地质条件下的迁移变化,在浅埋区某加油站开展了平、枯、丰水期的地下水监测工作。在水平分布上,TPH、BTEX、萘基本相似,均在加油岛附近形成高浓度区,而MTBE则更易随地下水流动而迁移,呈现出不同的污染晕。在垂直分布上,地下水的水位变动是污染物浓度分布的主要影响因素。     

Cytotoxicity, genotoxicity and ecotoxicity assay using human cell and environmental species for the screening of the risk from pollutant exposure

For the screening of the risk from environmental contamination, the cytotoxic/genotoxic effects of various model pollutants were determined using an in vivo system comprised of human HeLa cells; the ecotoxicity was also determined using the acute and genotoxicity tests on two aquatic sentinel species widely used in biomonitoring, namely, freshwater crustacean, Daphnia magna and larva of aquatic midge, Chironomus tentans. Nonylphenol (NP), bisphenol A (BPA), bis(2-ethylhexyl) phthalate (DEPH) and paraquat dichloride (PQ) were used as the model pollutants. The results showed that exposure of HeLa cells to NP, BPA and DEHP was sufficient for the expression of noticeable genotoxic and cytotoxic effects. Ecotoxicity results showed that, as expected, D. magna was more sensitive than C. tentans to chemical exposure. BPA may exert a genotoxic effect on D. magna and C. tentans, given that DNA strand breaks increased in both species exposed to this compound, whereas NP-induced DNA damage occurred only in C. tentans. In vivo genotoxic data obtained in aquatic sentinel species could provide valuable information for freshwater quality monitoring. From the results of the present study, the use of cytotoxic, genotoxic and ecotoxic tests using human cell system, as well as, biomonitoring species, seems to be relevant for preliminary evaluation of the human health and ecological effects of pollutants and thus, a promising screening tool for environmental monitoring and risk assessment.     

自然生态恢复过程中尾矿废弃地土壤微生物变化

尾矿废弃地是一种人为的裸地,其自然生态恢复过程表现为典型的生态系统原生演替过程.尾矿废弃地自然生态恢复过程为人们了解生态系统发展过程中土壤微生物群落的变化提供了一个良好的机遇.该研究以2处(即,铜陵杨山冲尾矿废弃地和铜官山新尾矿废弃地)不同时期弃置的、处于3个演替阶段(原生裸地阶段、隐花植物结皮阶段和草本维管植物群落阶段)的铜尾矿废弃地为研究对象,利用传统培养法(稀释平板法)和分子生物学法(净DNA含量法)相结合的手段对土壤微生物量和土壤微生物群落结构变化及其影响因素进行了调查.数据分析表明:随着尾矿废弃地上植物群落的形成和发展,尾矿废弃地水分含量增加、pH降低、土壤有机质和总氮质量分数提高;土壤微生物数量逐渐增加,维管植物群落下的尾矿废弃地中土壤微生物数量明显高于处于演替初期阶段的隐花植物结皮,高于裸地;不同演替阶段尾矿废弃地中土壤微生物群落结构表现为细菌(60.68﹪～97.45﹪)>放线菌(2.50﹪～39.13﹪)>真菌(0.05﹪～0.82﹪);相关分析发现,尾矿废弃地土壤微生物量变化与基质的含水量、总氮和有机质质量分数呈正相关,而与pH变化呈负相关.研究结果表明,在尾矿废弃地自然生态恢复过程中,伴随着植物群落形成、发展和基质理化性质的逐步改善,尾矿中土壤微生物也逐步恢复.     

重金属污染土壤植物修复研究进展

土壤重金属污染是当今世界面临的主要环境问题之一.植物修复定义为利用绿色植物去除环境中的污染物或使其无害化的生物技术.与传统环境修复技术相比,植物修复技术具有治理成本的低廉性,环境美学的兼容性,治理过程的原位性.本文主要对超富集植物的概念和特征、土壤重金属污染植物修复的方法和原理以及土壤重金属植物修复技术的强化措施进行了综述,并对植物修复的近期研究工作进行了展望.