糠醛厂生产过程安全评价

对企业生产过程中的危险有害因素进行安全评价,是当前企业预防事故发生的有效手段。安全评价技术在国内外已有较长的发展历史,但关于糠醛生产过程的安全评价方法及研究还比较匮乏。在糠醛生产过程中存在着火灾、爆炸、中毒、噪声等危险因素,极易造成大量的人员伤亡和财产损失。根据某糠醛厂的实际情况,结合安全评价的基本程序,采用重大危险源辨识及事故树分析评价法,对危险有害因素进行辨识和评价。结果显示,糠醛厂存在着锅炉超压爆炸的危险,利用事故树分析法可以及时的找出预防途径,有针对性地提出安全改进的合理建议,从而进一步改善糠醛厂生产过程中的环境。评价的结果对糠醛生产企业进行安全决策、减少事故隐患,具有积极的指导意义。     

杂质对硝酸铵水溶液临界爆炸温度的影响

利用自制装置对含杂质的硝酸铵水溶液临界爆炸温度进行测试研究.结果表明,Cl-单独作用在一定程度上抑制硝酸铵溶液的热分解,提高了其临界爆炸温度;pH值一定时,随着Cl-浓度的增大,硝酸铵水溶液的临界爆炸温度呈指数形式降低;Cl-浓度一定时,pH值越小,硝酸铵水溶液的临界爆炸温度越低;油脂会降低硝酸铵溶液的热稳定性.该结果...     

Advances in the treatment of multi-pollutant flue gas in China's building materials industry

In most of the world's building material industries, the control of flue gas pollutants mainly focuses on a single pollutant. However, given the large capacity and high contribution of China's building materials industry to global air pollution, the need to develop multi-pollutant emission reduction technology is urgent. Recently, China has focused on reducing the emissions of flue gas pollutants in the building materials industry, established many key research and development projects, and gradually implemented more stringent pollutant emission limits. This project focuses on the most recent advances in flue gas emission control technology in China's building materials industry, including denitration, dust removal, desulfurization, synergistic multi-pollutant emission reduction, and the construction of pilot research and demonstration projects for pollutant removal in several building material industries. On this basis, revised pollutant limits in flue gas emitted in China's building material industry are proposed.     

绿狐尾藻分解及其氮磷释放特征

湿地植物分解释放的有机物、氮和磷等会影响人工湿地对水体污染物的去除效率和出水水质.本研究采用尼龙分解袋法研究绿狐尾藻在水中的分解过程及氮磷释放特征.连续60 d的室内分解实验结果表明,前期(0～4 d)绿狐尾藻干物质质量损失速率快,占初始质量的30%,中后期(4～60 d)损失速率减慢,占31%.拟合的一级动力学分解速率常数为0. 014 2d-1,降解50%的干物质需48. 8 d.水体p H值变化情况:0～4 d从7. 60迅速下降到5. 63;中期趋于稳定;后期p H值回升到7. 03,与空白对照值接近.绿狐尾藻分解实验系统中溶解氧浓度从6. 30 mg·L~(-1)在1 d内快速下降到0. 61 mg·L~(-1),表明该系统一直处于厌氧状态.水中总氮浓度0～2 h迅速增加达到12. 7 mg·L~(-1),2 h～32 d逐渐降低到5. 80 mg·L~(-1),后期略有增加;总磷浓度初期快速升高到18. 4 mg·L~(-1),中后期趋于稳定.有机氮(占总氮65. 7%～94. 7%)和无机磷(占总磷61%～89%)是主要的氮磷存在形态.绿狐尾藻体内总氮含量随分解时间逐渐增加,从24. 3 mg·g~(-1)上升到60. 5 mg·g~(-1);而总磷含量从6. 09 mg·g~(-1)下降到2. 94 mg·g~(-1)后波动稳定,这可能与附着微生物对氮的吸收和固定等因素有关.本研究证实绿狐尾藻分解过程释放的氮磷营养元素会引起水体二次污染,为此采用合理的植物收割管理措施非常必要.     

嗜水气单胞菌强化老化纳米零价铁去除水中Cr(VI)

基于老化对纳米零价铁（NZVI）去除水中Cr（VI）的不利影响,本研究考察了接种嗜水气单胞菌（Aeromonas hydrophila）强化老化NZVI对水中Cr（VI）的去除,并分析了溶解氧、温度、pH、Cr（VI）初始浓度对其去除Cr（VI）的影响,同时利用扫描电镜（SEM）、X射线光电子能谱（XPS）等分析了反应前后材料的形貌特征及Cr的价态变化.结果表明,接种嗜水气单胞菌能显著提高无氧条件下老化NZVI对Cr（VI）的去除效果,且在酸性条件和30~40 ℃条件下去除效果较好,可能是因为该条件下更有利于老化NZVI的腐蚀和微生物的生长,此外,Cr（VI）去除效率随Cr（VI）初始浓度升高而降低.在pH=6,温度为30 ℃,老化nZVI投加量为0.1 g·L^-1,Cr（VI）初始浓度为50 mg·L^-1的条件下反应24 h后,Cr（VI）的去除率可达到100%.XPS分析表明,反应后NZVI表面沉积的Cr主要以Cr（III）的形式存在,可能为Cr（OH）₃沉淀或Fe_xCr_1-x（OH）₃共沉淀物.动力学研究发现,Cr（VI）去除过程符合准二级动力学,去除机制为Cr（VI）的吸附、还原与共沉淀,其中以还原作用为主.     

Distribution and source of microplastics in China's second largest reservoir - Danjiangkou Reservoir

Fresh water microplastic pollution is of pressing concern globally, but its distribution and sources in reservoirs are poorly documented. Danjiangkou Reservoir is the second largest reservoir in China and is divided into the Han Reservoir and Dan Reservoir. In this work, microplastic abundances and morphological characteristics of the reservoir were investigated. The microplastic abundance of 15 main tributaries of the reservoir was also measured. The vertical distribution (in water column and sediment), horizontal distribution (in Han Reservoir and Dan Reservoir) and source of microplastics were analyzed. Microplastics accumulated in the middle layer of the reservoir, and the size and color of the microplastic particles changed from the surface to the bottom, which implies that surveys of surface water are not enough to determine the microplastic contamination for deep water reservoirs. In the surface water, the microplastic abundance in the Han Reservoir was lower than that in the Dan Reservoir (p < 0.05), but microplastic abundance did not differ significantly in the intermediate and bottom water. Tributaries were one of the main sources of microplastics for Han Reservoir but not for Dan Reservoir. Agricultural cultivation in the hydro-fluctuation belt might be an important source of microplastics in the Dan Reservoir, which should be given additional attention. The results of this study can provide valuable information for developing microplastic sampling strategies in deep water reservoirs. Further studies are recommended to investigate the process through which microplastics in the hydro-fluctuation belt enter the reservoir and the sinking behavior of microplastics in the reservoir.     

生活垃圾填埋场封场后种植植物中重金属迁移研究

在上海老港生活垃圾填埋场填埋单元封场的覆盖土中掺混了矿化垃圾种植植物,分析Cd、Pb、Cu、Zn 4种重金属在土壤和植物中的迁移变化,研究表明:(1)覆盖土土质从一般耕作土变成肥沃土壤;覆盖土和种植混合土重金属Cd、Pb、Cu、Zn中Cd、Pb含量相近,但种植土的Cu含量略大于覆盖原土,Zn含量远大于覆盖原土;(2)植物能富集土壤和垃圾中的重金属,木本植物的根部富集重金属的能力强于草本植物,但重金属在草本植物根、茎、叶中的迁移速度大于木本植物;(3)植物根、茎、叶的Cu、Zn含量均远大于未受污染土壤种植植物相应部位的Cu、Zn含量,种植的植物不能供家养动物食用,以免通过食物链作用危及人体安全.     

Recovery elemental sulfur from calcium sulfide prepared by red gypsum in sulfuric acid wastewater treatment

Journal of Material Cycles and Waste Management - Red gypsum comes from TiO2 production industry by sulfate method, which comes from the low acidic liquid stream treatment using lime or limestone....     

Characteristics,decoupling effect,and driving factors of regional tourism’s carbon emissions in China

Environmental Science and Pollution Research - By revealing the temporal and spatial differentiation of China’s regional tourism carbon emissions and its decoupling relationship with tourism...     

Influence of different inoculation densities of black soldier fly larvae (Hermetia illucens) on heavy metal immobilization in swine manure

The disposal of organic waste by the biocomposting of black soldier fly larvae (BSFL) has drawn broad attention. However, the discrepancies in heavy metal immobilization between BSFL biocomposting with different inoculation densities and aerobic composting need to be further researched. In this study, BSFL with inoculation densities of 0.08%, 0.24% and 0.40% was added to swine manure to investigate its influence on heavy metal bioaccumulation and bioavailability. The physicochemical properties, BSFL growth performance and amino acid contents were measured. The results showed that the germination index, total prepupal yield and bioavailable fraction removal rate (%) of Cr and Pb at an inoculation density of 0.40% of BSFL were the highest among all of the BSFL biocomposting groups. Although the bioaccumulation factor and heavy metal (Cd, Cr, Cu and Zn) concentrations of the BSFL body from swine manure with inoculation densities of 0.24% and 0.40% of BSFL were similar, the BSFL inoculation density of 0.40% had the best absorption effect on these heavy metals in terms of total prepupal yield. Therefore, this study provides a basis for exploring the optimal inoculation density of BSFL biocomposting to reduce the harmful effects of heavy metals in swine manure.