Effect of super absorbent polymer sodium polyacrylate on the bacterial community and associated chemistry of loessial soil

ABSTRACT

Super absorbent polymers (SAPs) have been applied as soil conditioners to reduce soil water loss, but there are few studies about how SAPs affect structures of soil bacterial community, and these associated chemical residues are uncertain. Treatments under different soil moisture conditions by application of sodium polyacrylate in repacked soil columns were used to investigate their effects on the soil bacterial community structures by Illumina MiSeq sequencing. Alpha diversity analysis showed that adding SAPs had an impact on bacterial diversity. On phylum level, adding SAPs significantly reduced the amount of Actinobacteria (1.9–2.4-fold), Bacteroidetes (1.1–2.1-fold) while increased the amount of Firmicutes (1.9–4.6-fold). At genus level, effects of SAPs on the soil bacterial community structures varied with the soil moisture conditions. Under water deficit, SAPs reduced the soil pH, which promoted the proliferation of Lactobacillus (9.9–29.1-fold), and acid production by these bacteria might further promote the reduction of pH, potentially inhibiting growth of Acidobacteria (1.3–1.8-fold) and Chloroflexi (1.6–2.3-fold). The pyrolysis analysis showed that some substances such as methanesulfonyl chloride, long-chain amides and esters, were only derived from water-saturated soil treated with SAPs, which might subsequently have negative impacts on the environment and associated agriculture.     

生物质热解柔性输送装置性能研究

为了解决生物质连续热解装置的螺旋绞龙与热解管因热变形而发生的机械干涉现象,研究了一种用于生物质热解的无轴柔性连续输送装置,设计了该无轴柔性螺旋叶片参数。以稻壳、木屑和黄豆为输送物料,探究了螺距、转速和有轴、无轴等因素对输送性能的影响。结果表明:柔性输送装置的输送能力随着螺距的增加而增强,在中低转速下,物料的处理量随着转速的增加呈线性增加,表明物料的输送量和通过时间可通过调节电机转速实现精准控制;无轴螺旋输送能力比有轴螺旋增加15%~30%,且输送过程平稳,避免了物料在输送装置与输送管之间发生挤压、进而出现死机的现象。     

Tandem size exclusion chromatography-Polyacrylamide gel electrophoresis of humic acids

Humic acids (HAs) from four soils were fractionated by size exclusion chromatography (SEC) on Sephadex G-75. Three fractions were obtained in all humic acids, collected and assayed by Polyacrylamide gel electrophoresis (PAGE). The unfractionated HA from each soil was used as reference. Each chromatographic fraction formed one electrophoretic zone corresponding closely to one band of the reference sample with some admixture of the fractions preceding or following. The results indicate that fractionation of HAs by tandem SEC-PAGE can be successfully used for obtaining fractions of reduced polydispersity and different electrophoretic mobilities. Pyrolysis/methylation-gas chromatography-mass spectrometry of the full size preparations of HA and fractions with exactly defined molecular size and electrophoretic mobility showed a different distribution in humic components, mainly lipids, lignin derivatives and N-containing compounds.     

生物炭之低碳农业初探

农业生产过程与全球气候变化息息相关,如何减少农业温室气体排放,并探寻土壤固炭方法已经成为当前农业与环境研究中的热点。全文旨在摸索一条由生物质碳化技术为基础的低碳农业发展的可能途径。从低碳这一热点问题出发,本文对低碳农业的定义、特征、途径进行了基本阐述,同时论述了生物炭的基本特征,及生物炭在应用上的农学和环境学价值,并重点讨论了如何利用生物炭发展以低能耗、低排放、低污染为特征的低碳农业的可能模式,最后指出了当前生物炭在低碳农业研究和利用方面所面临的问题和挑战。     

枸杞多糖的热裂解产物研究

利用裂解气相—色谱质谱联用(Py-GC/MS)对卷烟燃烧过程进行模拟,研究枸杞多糖在无氧条件下的热裂解,以期为枸杞多糖在卷烟中的应用提供一些理论基础。用GC-MS定性定量测定分析热裂解产物。比较了不同温度(300,600,900℃)下的裂解产物差异,对裂解产物进行了归类分析,并分析了主要裂解产物致香成分的致香效果,为卷烟评吸提供了理论依据。     

生物油分级冷凝研究进展

对生物油分级冷凝的最新成果进行了总结和分析。在分级冷凝装置方面,阐述了通过多种复合式分级冷凝系统在线分离收集生物油的研究现状与进展;从生物油分级产物的理化性质角度分析了生物油高品质利用、提取高价值化工原料的可能性;同时指出了生物油分级冷凝研究中仍存在的问题及未来的研究趋势。     

生物质热解气燃烧装置设计与燃烧特性试验

针对目前生物质热解气中焦油去除困难、焦油能量难以利用等问题,结合现有燃气燃烧器相关技术,开展了生物质热解气直接燃烧技术研究与试验。燃烧器理论耗气量为2~5 m~3/h,通过理论计算确定了燃烧器参数,设计了卧式燃烧室并安装烟气催化裂解装置及烟气检测装置,搭建了热解气燃烧试验平台,并对热解气的燃烧特性进行了试验研究。以花生壳为原料,在碳化温度500℃、滞留时间30 min的条件下进行连续热解碳化,产生的高温热解气直接通入燃烧设备。结果表明,燃烧设备性能较好,热解气燃烧过程稳定,燃烧效率达到98.5%,在催化剂的作用下,燃烧效率提高到98.9%,满足设计要求。     

典型废弃生物质的热解特性研究

对6种典型废弃生物质(锯末、稻壳、纸屑、橱芥、废塑料、废橡胶)进行热重实验分析及热解动力学分析;同时,利用TG/DTG曲线分析了它们的基本热解特性,包括热解区间、最大热解速率的温度、不同加热速度等对热解进程的影响等;通过热解动力学分析,给出了基本的热解动力学方程,研究了各种原料在不同升温速率下的热解动力学参数,为废弃生物质制取生物质能源技术提供基础数据.     

生物质醋液生产原料筛选及其转化技术研究

中国是农业大国,农林生物资源丰富,但农林生物质利用还很局限,项目将从植物资源综合利用的角度出发,重点介绍生物质醋液生产原料的筛选、基本理化性质与得率的变化情况以及转化技术的研究,并确定生物质醋液的最佳工艺参数和生产流程。最终寻求一种农林生物质高效、无公害、资源化利用的方法,研制出高效稳定的醋液,对下一步作为植物生长调节剂、发展有机生态农牧业和走可持续发展之路提供技术支撑和服务平台。试验结果表明：在相同条件（温度、通风量等）下,以芦苇为原材料,将含水率调节到15%左右,热解温度调到600℃,通过精制方法所获得的醋液得率高,焦油含量低,质量好,再利用静置方法静置4~6个月,所获得的醋液pH变化小、性质较为稳定、成本低、效果最好。