EMERGY analysis for sustainability evaluation of the Baiyangdian wetland ecosystem in China

This study presents a quantitative and ecological benefit evaluation of the Baiyangdian wetland in China between the years 2000 and 2006. Methods of EMERGY analysis were applied to illustrate the wetland ecosystem, to evaluate the economic and environmental inputs and consequent yields, and to assess the sustainability of the Baiyangdian wetland. The indicators for the integrated ecological and economic system, such as EMERGY yield ratio (EYR) (7.51), EMERGY investment ratio (EIR) (4.52), environmental loading ratio (ELR) (2.92), EMERGY exchange ratio (0.41), and EMERGY sustainable indicator (ESI) (2.57) were calculated, compared, analyzed, and discussed. The non-renewable investment in Baiyangdian was greater than renewable investment, leading to the unsustainable development of the system. High EYR indicated that the Baiyangdian integrated system had created huge profits for its people, while ELR and ESI revealed that human behavior has been a heavy burden on the environment, and countermeasures should be taken by the Chinese government to relieve and resolve these problems. Potential management methods were also proposed in this paper.     

A mini-microbial fuel cell for voltage testing of exoelectrogenic bacteria

Current methods for testing the electricity generation capacity of isolates are time- and labor-consuming. This paper presents a rapid voltage testing system of exoelectrogenic bacteria called Quickscreen, which is based on a microliter microbial fuel cell (MFC). Geobacter sulfurreducens and Shewanella baltica were used as the model exoelectrogenic bacteria; Escherichia coli that cannot generate electricity was used as a negative control. It was found that the electricity generation capacity of the isolates could be determined within about five hours by using Quickscreen, and that its time was relatively rapid compared with the time needed by using larger MFCs. A parallel, stable, and low background voltage was achieved using titanium as a current collector in the blank run. The external resistance had little impact on the blank run during the initial period. The cathode with a five-hole configuration, used to hydrate the carbon cathode, gave higher cathode potential than that with a one-hole configuration. Steady discharge and current interrupt methods showed that the anode mostly contributed to the large internal resistance of the Quickscreen system. However, the addition of graphite felt decreased the resistance from 18 to 5 kΩ. This device was proved to be useful to rapidly evaluate the electricity generation capacity of different bacteria.     

改性高炉渣对甲基橙的吸附

以盐酸和十六烷基三甲基溴化铵对包钢高炉渣进行表面改性,通过XRD、SEM和N2吸附-脱附测试研究其微观结构和孔径分布,并以阴离子型染料甲基橙溶液为模拟染料废水研究其吸附性能,进而探索最佳改性制备条件。研究结果表明：有机改性高炉渣主要化学成分为SiO2,表面有明显的孔道结构,比表面积高达394.5 m2·g-1,平均孔径为12.4 nm;有机改性高炉渣对甲基橙溶液均具有较强的吸附性能,最佳改性条件为加入改性剂盐酸浓度为3 mol·L-1、十六烷基三甲基溴化铵的最终投加浓度为8 g·L-1、水热温度160 ℃和16 h,此时所制备的有机改性高炉渣吸附性能最强,吸附率为98.06%,最大吸附量达357.14 mg·g-1。等温吸附实验表明,有机改性高炉渣对甲基橙溶液的吸附属于多分子层吸附。     

燃煤飞灰负载钾基CO2吸收剂再生反应特性的动力学分析

采用热重分析的方法对吸收剂的再生反应进行研究,说明了燃煤飞灰负载钾基CO2吸收剂的制备方法,探讨了在不同升温速率下燃煤飞灰负载钾基CO2吸收剂和纯KHCO3的再生反应特性。结果表明: 燃煤飞灰负载吸收剂的峰值失重速率为0.13~0.73 mg?min-1,在升温速率为20 ℃?min-1时,反应温度区间最小,为94.34 ℃;采用多种分析方法对吸收剂的受热分解反应进行动力学分析,纯KHCO3的反应活化能为85.7~92.0 kJ·mol-1;燃煤飞灰负载钾基CO2吸收剂的反应活化能为66.2~69.4 kJ·mol-1,随着转化率上升,2种样品的活化能均先减小后增大。燃煤飞灰负载钾基吸收剂再生反应的活化能小于纯KHCO3的活化能,说明将KHCO3负载于燃煤飞灰上有利于再生反应的进行。     

改性糠醛渣吸附脱硫废水中钙离子

石灰石-石膏法烟气脱硫技术中石灰石利用率低导致钙流失严重,为实现脱硫废水中Ca2+的资源化利用,进行糠醛渣改性和Ca2+的吸附特性研究。实验结果表明,利用H3PO4改性后的糠醛渣对脱硫废水中Ca2+具有较高的吸附率;在振荡的前30 min吸附率上升极快,至90 min时基本达到平衡吸附量;对Ca2+浓度对吸附率影响研究结果表明,平衡吸附量与平衡浓度关系符合Langmuir等温吸附方程;在初始Ca2+浓度为300 mg/L的溶液中加入3 g吸附剂,温度30℃条件下振荡90 min,平衡吸附量为8.41 mg/g。     

生物酶生态修复重金属污染土壤

以多种重金属污染的土壤为材料,研究了酶对重金属的去除效果.在单因素实验基础上,采用响应面法对重金属去除的反应条件进行优化,结果表明,α-淀粉酶质量浓度0.2%、pH 3.5、反应时间12 h为最佳淋洗修复条件,Cd、Cr、Cu、Ni、Zn去除率分别为82.36%、75.02%、38.38%、34.69%和57.54%,去除率的大小顺序为Cd >Cr >Zn >Cu >Ni.酶作为土壤的组成部分,利用酶修复重金属污染的土壤,可以降低环境风险,具有较好应用前景.     

基于文献计量分析的场地化学氧化修复技术研究热点和趋势

化学氧化修复技术具有污染物去除效率高、修复周期短和成本低等优势,在污染场地修复领域具有广阔的应用前景。基于Web of Science数据库,通过文献计量可视化软件VOSviewer和CiteSpace,分析了1990—2022年场地污染土壤和地下水化学氧化修复领域的研究热点及趋势。结果表明,1990—2022年年度发文量呈增长趋势,中国和美国是发文量排名前二的国家,2010年后中国年发文量快速增加并位居第一,中国科学院在发文量及被引频次方面均高居榜首。基于关键词分析,总结归纳了化学氧化修复技术适用污染物类型、氧化剂种类和催化/活化方法以及化学氧化联合修复技术。当前研究热点集中在催化/活化方法研发、污染物降解机理探究以及在土壤和地下水中修复应用等方面;未来研究重点将聚焦于研发新型氧化剂和靶向催化/活化材料,探究材料迁移扩散机制和活性氧化物质产生机理,发展协同化学氧化修复技术体系并推进工程化应用,以及建立化学氧化修复全过程风险监测和评价体系。     

鸟粪石负载硅藻土对土壤铅和金霉素的同步修复作用

使用镁盐改性硅藻土回收沼液中氮磷制得鸟粪石负载硅藻土 (Struvite-loaded diatomite,SD) ,将其用于土壤中铅 (Pb) 和金霉素 (CTC) 复合污染的原位修复。采用吸附-解吸实验评估SD对Pb和CTC迁移特性的影响,同时,通过测定土壤pH和酸缓冲能力、土壤Pb和CTC的有效态和形态、土壤速效磷和微生物群落结构变化等考察SD对土壤Pb和CTC的钝化能力,借助SEM、XRD、FT-IR等表征手段揭示其修复机理。结果表明,SD能有效降低Pb和CTC在土壤中的迁移特性;SD投加质量分数为3%,稳定49 d后,土壤酸中和能力提升1倍以上,土壤有效态Pb和CTC含量分别降低26%和56%,酸溶态Pb占比降低10%,残渣态Pb占比升高18%, CTC的水溶态和松散结合态占比分别降低5%和13%,紧密结合态CTC升高11%,一定程度上降低了Pb和CTC在土壤中的生物有效性;SD的投加可提升土壤速效磷含量,提高土壤微生物的相对丰度和多样性,尤其增加酸杆菌门 (Acidobacteria) 、绿弯菌门 (Chloroflexi) 和芽单胞菌门 (Gemmatimonadetes) 的相对丰度,降低放线菌门 (Actinobacteria) 和厚壁菌门 (Firmicutes) 的相对丰度;SD对土壤Pb和CTC的钝化机制主要为吸附和沉淀的协同作用。该研究可为污水氮磷资源化利用和重金属抗生素复合污染土壤原位修复提供参考。     

活性污泥和生物膜复合模型的建立与模拟

针对近年来出现的城市污水处理厂活性污泥和生物膜复合工艺,首先建立了能同时描述碳氧化、脱氮和除磷的修正ASM1（Activated Sludge Model No.1）,以及与ASM1中微生物生长过程速率方程结构形式相同、物理意义明确的生物膜模型。然后将该生物膜模型与修正的ASM1相结合,形成了活性污泥和生物膜复合模型,利用VB6.0编写了相应的模拟软件。以西安市第五污水处理厂复合工艺为对象,对其碳、氮和磷的去除进行模拟,结果表明该模型可以较好地反映出水各污染指标的变化规律。通过对进水流量、填料区的位置及填料区填料的投加率进行模拟,为填料区的优化和系统运行提出了建议。