Immobilization of NZVI in polydopamine surface-modified biochar for adsorption and degradation of tetracycline in aqueous solution

Polydopamine/NZVI@biochar composite (PDA/NZVI@BC) with high removal efficiency of tetracycline (TC) in aqueous solutions was successfully synthesized. The resultant composite demonstrated high reactivity, excellent stability and reusability over the reaction course. Such excellent performance can be attributed to the presence of the huge surface area on biochar (BC), which could enhance NZVI dispersion and prolong its longevity. The carbonyl group contained on the surface of biochar could combine with the amino group on polydopamine(PDA). The hydroxyl groups in PDA is able to enhance the dispersion and loading of NZVI on BC. Being modified by PDA, the hydrophilicity of biochar was improved. Among BC, pristine NZVI and PDA/NZVI@BC, PDA/ NZVI@BC exhibited the highest activity for removal of TC. Compared with NZVI, the removal efficiency of TC could be increased by 55.9% by using PDA/NZVI@BC under the same conditions. The optimal modification time of PDA was 8h, and the ratio of NZVI to BC was 1:2. In addition, the possible degradation mechanism of TC was proposed, which was based on the analysis of degraded products by LC-MS. Different important factors impacting on TC removal (including mass ratio of NZVI to BC/PDA, initial concentration, pH value and the initial temperature of the solution) were investigated as well. Overall, this study provides a promising alternative material and environmental pollution management option for antibiotic wastewater treatment.

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基于数值模拟的青岛市O3快速来源解析

为了建立臭氧污染快速来源解析方法,提高解析结果的时空分辨率,以2017、2018年青岛市环境空气质量精细化管理实践为契机,利用CAMx-OSAT模型的污染源识别与追踪技术,预测解析未来时段特别是污染期间不同区域、行业的排放源对目标站点O3浓度的贡献量和贡献率。结果显示:模拟的春、夏季2个时段青岛市的O3来源主要为工业、电厂、交通、生活源,2个时段的模拟结果本地和外来源中工业源的贡献分别占62. 0%和65. 0%,交通源分别占24. 5%和16. 0%,生活源分别占8. 4%和8. 0%,电厂源分别占5. 0%和11. 0%,O3高浓度污染时,工业源的贡献上升明显,青岛市的O3浓度外来源的贡献约占40%~80%。该数值模型O3来源解析及预测方法已成功用于青岛市的空气质量精细化管理及应急管控。     

纳米铁与微生物联合去除地下水中的NO_3~--N

采用实验模拟装置考察油酸包覆型纳米铁、反硝化细菌及其组合方法处理地下水NO-3-N效果与反应产物的变化特征。结果表明,在模拟地下水溶解氧(0.50 mg/L)、温度(15℃)和黑暗环境中,2 g油酸包覆型纳米铁与70 mg/L NO-3-N反应,11 d后NO-3-N去除率为86.4%,其中74.7%的还原产物为NH+4-N,1.7%为NO-2-N,N2生成量仅占10%;反硝化细菌体系中,反应6 d后NO-3-N去除率为78.6%,此时未检测到NH+4-N,而NO-2-N达到最大值,为60.1%,仅有18.5%的N2生成;在油酸包覆型纳米铁-反硝化细菌耦合体系中,6 d后NO-3-N去除率达到80.3%,其中NH+4-N占17.6%,NO-2-N为30.1%,N2为32.6%。因此,比较3种材料对NO-3-N降解效果及产物得出,在地下水环境中,油酸包覆型纳米铁-反硝化细菌组合方法对地下水NO-3-N的去除效果最好,产物主要是N2,减少了还原产物NH+4-N对地下水造成的二次污染。     

Sustainable farming practices of the Chinese mitten crab (<Emphasis Type="Italic">Eriocheir sinensis)</Emphasis> around Hongze Lake,lower Yangtze River Basin,China

Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake (118.48–118.72°E; 33.36–33.38°N) are reported. Area farmed has remained relatively unchanged but production (59 932 t in 2012) increased steadily over the last 7 years, indicative of the viability and sustainability of the farming system that has gradually replaced intensive Chinese major carp polyculture around Hongze Lake. Results showed that production range was 135–2400 kg ha⁻¹ cycle⁻¹ (mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed to a normal distribution curve, with 66.7 % of farms yielding 900 kg ha⁻¹ cycle⁻¹ or more. Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0722-0) contains supplementary material, which is available to authorized users.     

Effects of temperature and relative humidity on the methane permeability rate of biogas storage membranes

Selecting a material for biogas storage membranes is becoming increasingly vital because of the wide applications of biogas storage membranes in biogas plants. Material selection has numerous influencing factors, including gas permeability, strength, density, and so on. Among these, gas permeability has a vital role in biogas storage membranes. In this study, three kinds of biogas storage membranes with the same thickness were selected to investigate the effects of temperature (10, 20, 30, and 40°C) and relative humidity (RH; 0%, 50%, and 100%) on the permeability rate of biogas storage membranes. Results demonstrated that when various membrane samples with the same RH values were tested, temperature exhibited a strong effect on permeability rate. Kinetic analysis showed that the relationship between permeability and temperature agrees with the Arrhenius equation. However, no remarkable variation in methane permeability was observed for membranes with the same temperature but different RH values, thus suggesting that RH nearly has no obvious direct influence on the permeability rate of membranes.     

应用改进分光光度法测定多组分水样的COD

提出改进分光光度法测定多组分水样的化学需氧量(COD)。以多种物质的吸光曲线回归方程,将实时测得的水样吸光度分解成多种物质的吸光度,利用多元一次方程进行求解并计算出COD的方法。新方法对含邻苯二甲酸氢钾和丙烯酰胺水样测量的COD,误差平均值为+5.0%,对更多组分的水样测量紫外吸光度误差较大,通过引入修正系数修正后误差大幅下降,10次测量的变异系数约0.5%,精密度较好。通过分析新方法实际运用时存在的优劣之处,提出综合高锰酸盐指数(CODMn)来弥补其测量上不足的新型废水监测模式,以实现监测的快速测量、低耗能、低污染和实时性。     

施用垃圾堆肥土壤重金属在不同温度和酸雨条件下的淋溶特征

采用淋洗法,研究了垃圾堆肥中重金属在不同温度与模拟酸雨条件下的淋溶特征。结果表明,随着淋洗次数的增加,淋洗液中Cd、Cr、Cu、Ni和Pb的含量都有很大程度的减少。Cd、Cr、Cu和Ni 4种金属在模拟酸雨的情况下淋出量明显高于蒸馏水的情况,增幅都在116%和351%之间,差异显著(P<0.05)或极显著(P<0.01),而酸雨对Pb的淋出影响较小。在酸雨淋洗下,重金属的淋出率在30℃时达到最大,其中Ni随着温度的变化相对较小。而在蒸馏水淋洗下,重金属的淋出率随着温度的变化相对平稳。此外,5种重金属的淋出率明显不同,其中Cr和Ni的淋出率相对较大,Pb最小。     

KH-560交联壳聚糖固载β-环糊精薄膜对硝基苯酚的吸附行为

研究了KH-560交联壳聚糖固载β-环糊精薄膜对4-硝基苯酚、2,4-二硝基苯酚和2,4,6-三硝基苯酚的吸附行为,测定了吸附质浓度、pH、温度和吸附时间对其吸附性能的影响,并进行了热力学拟合。研究结果表明,在中性条件下,298K下吸附4-硝基苯酚在40min时可以达到平衡;随着硝基数目的增加,吸附量增大;随着温度的升高,吸附量减小;吸附过程用Langmuir模型描述更合适。     

Biosorption of divalent Pb, Cd and Zn on aragonite and calcite mollusk shells

The potential of using mollusk shell powder in aragonite (razor clam shells, RCS) and calcite phase (oyster shells, OS) to remove Pb²⁺, Cd²⁺ and Zn²⁺ from contaminated water was investigated. Both biogenic sorbents displayed very high sorption capacities for the three metals except for Cd on OS. XRD, SEM and XPS results demonstrated that surface precipitation leading to crystal growth took place during sorption. Calcite OS displayed a remarkably higher sorption capacity to Pb than aragonite RCS, while the opposite was observed for Cd. However, both sorbents displayed similar sorption capacities to Zn. These could be due to the different extent of matching in crystal lattice between the metal bearing precipitate and the substrates. The initial pH of the solution, sorbent’s dosage and grain size affected the removal efficiency of the heavy meals significantly, while the organic matter in mollusk shells affected the removal efficiency to a lesser extent.     

燃煤电厂袋式除尘器气流分布物理模型实验研究

根据相似理论建立了针对某燃煤电厂新建袋式除尘器工程的气流分布物理模型实验装置,并对其在典型工况下的气流分布情况进行了实验和分析.在此基础上,通过增加导流板和改变气流分布板的组合方式等措施,调整优化系统的气流分布情况,得出了适用于该项工程的气流分布设计和优化方案.