Sustainable wood-based nanotechnologies for photocatalytic degradation of organic contaminants in aquatic environment

•Wood and its reassemblies are ideal substrates to develop novel photocatalysts. •Synthetic methods and mechanisms of wood-derived photocatalysts are summarized. •Advances in wood-derived photocatalysts for organic pollutant removal are summed up. •Metal doping, morphology control and semiconductor coupling methods are highlighted. •Structure-activity relationship and catalytic mechanism of photocatalysts are given. Wood-based nanotechnologies have received much attention in the area of photocatalytic degradation of organic contaminants in aquatic environment in recent years, because of the high abundance and renewability of wood as well as the high reaction activity and unique structural features of these materials. Herein, we present a comprehensive review of the current research activities centering on the development of wood-based nanocatalysts for photodegradation of organic pollutants. This review begins with a brief introduction of the development of photocatalysts and hierarchical structure of wood. The review then focuses on strategies of designing novel photocatalysts based on wood or its recombinants (such as 1D fiber, 2D films and 3D porous gels) using advanced nanotechnology including sol-gel method, hydrothermal method, magnetron sputtering method, dipping method and so on. Next, we highlight typical approaches that improve the photocatalytic property, including metal element doping, morphology control and semiconductor coupling. Also, the structure-activity relationship of photocatalysts is emphasized. Finally, a brief summary and prospect of wood-derived photocatalysts is provided.     

Lagged effect of exports,industrialization and urbanization on carbon footprint in Southeast Asia

The study aims to examine lagged causal effect of economic development policies on the carbon footprint of Southeast Asia. This study employs unit root test, cointegration test and panel data analysis methods to examine endogeneity concerns in observational data. The study applies panel data analysis methods to address unobserved country effect in the model. The balanced panel data includes a total of 240 observations with five cross sections of five nations in Southeast Asia and with 48 time-specific periods of 1970–2017. The results indicate that (1) exports, industrialization, urbanization and economic growth have lagged negative effect on the carbon footprint of the region in the short-run, and (2) there exists a long-run equilibrium relationship among exports, industrialization, urbanization, economic growth and carbon footprint in the region. The findings suggest that the economic growth, exports, industrialization and urbanization of the developing countries in Southeast Asia have been achieved at the cost of increasing the carbon footprint of the region. The findings imply that the environmental policy of the export-led growth countries never have been effective so far since the nations have achieved their economic growth at the high cost of harming the environment of the nations.     

利用活性污泥制造活性炭的研究

论述了利用在活性污泥法处理废水过程中产生的好氧污泥和厌氧污泥制造活性炭的过程,选择出最佳的制作条件,并进一步测试了产品的性能。实验结果表明,利用剩余活性污泥制造活发现灰这一方法是可行的,并且在最佳条件下制成的活性炭的吸附性能比较令人满意。     

于桥水库网箱养鱼对水质影响分析

本文通过采样监测分析了网箱养鱼对水质的影响。分析结果表明,网箱养鱼明显增加了水库水体中藻类密度ＣＯＤ、ＴＰ、ＴＮ的含量,并引起水温上升,溶解氧减少,促进水库富营养化进程,是水质恶化的重要之一。同时,残余饵料和粪便的沉积,增加了底质中的有机质ＴＰ和ＴＮ,造成水库水体的二次污染。     

Source diagnostics of polycyclic aromatic hydrocarbons in urban road runoff, dust, rain and canopy throughfall

Diagnostic ratios and multivariate analysis were utilized to apportion polycyclic aromatic hydrocarbon (PAH) sources for road runoff, road dust, rain and canopy throughfall based on samples collected in an urban area of Beijing, China. Three sampling sites representing vehicle lane, bicycle lane and branch road were selected. For road runoff and road dust, vehicular emission and coal combustion were identified as major sources, and the source contributions varied among the sampling sites. For rain, three principal components were apportioned representing coal/oil combustion (54%), vehicular emission (34%) and coking (12%). For canopy throughfall, vehicular emission (56%), coal combustion (30%) and oil combustion (14%) were identified as major sources. Overall, the PAH's source for road runoff mainly reflected that for road dust. Despite site-specific sources, the findings at the study area provided a general picture of PAHs sources for the road runoff system in urban area of Beijing.     

Performance and mechanism of carbamazepine removal by FeS-S2O82– process: experimental investigation and DFT calculations

● Synergistic removal of carbamazepine (CBZ) was obtained in the FeS-S₂O₈^2– process. ● SO₄^•− and •OH were identified as the main radicals in the FeS-S₂O₈^2– process. ● Heterogeneous oxidation would be dominant first, followed by homogeneous reaction. ● Degradation pathway of CBZ was well elucidated by experiments and DFT calculations. As persulfate (S₂O₈^2–) is being increasingly used as an alternative oxidizing agent, developing low-cost and eco-friendly catalysts for efficient S₂O₈^2– activation is potentially useful for the treatment of wastewater containing refractory organic pollutant. In this study, the degradative features and mechanisms of carbamazepine (CBZ) were systematically investigated in a novel FeS- S₂O₈^2– process under near-neutral conditions. The results exhibited that CBZ can be effectively eliminated by the FeS-S₂O₈^2– process and the optimal conditions were: 250 mg/L FeS, 0.5 mmol/L S₂O₈^2–, and pH = 6.0. The existence of Cl⁻ (1 and 50 mmol/L) has little influence on the CBZ elimination, while both HCO₃⁻ and HPO₄²⁻ (1 and 50 mmol/L) significantly suppressed the CBZ removal in the FeS-S₂O₈^2– process. CBZ could be degraded via a radical mechanism in the FeS-S₂O₈^2– process, the working radical species (i.e., SO₄^•− and •OH) were efficiently formed via the promoted decomposition of S₂O₈^2– by the surface Fe²⁺ on the FeS and the dissolved ferrous ions in solution. Based on the identified oxidized products and Fukui index calculations, a possible degradation pathway of CBZ was speculated. More importantly, a two-stage oxidation mechanism of CBZ elimination was speculated in the FeS-S₂O₈^2– process, the activation of S₂O₈^2– by the surface-active Fe^(II) of FeS dominated in the initial 5 min, while homogeneous oxidation reactions played more essential parts than others in the following reaction stage (5–60 min). Overall, this study demonstrated that the FeS-S₂O₈^2– process is capable of removing CBZ from water efficiently.     

城市降雨径流人工湿地处理的效能研究

根据广东省东莞市同沙水库集水区的降雨径流的平均水质特征,采用改进的人工湿地系统对其污染物的降解效果和耐冲击负荷能力进行了模拟研究,实验中人工模拟城市降雨径流污染物平均浓度COD为169.19 mg/L、TP为0.58 mg/L、TN为5.69 mg/L和NH4+-N为3.69 mg/L.实验结果表明,该湿地系统各对污染...     

武汉市城区大气监测优化布点研究

对武汉市城区网格布点实测ＴＳＰ、ＳＯ２获取了城区大气污染总体水平的数据，运用Ｆｉｓｈｅｒ最优分割方法，求出城区５个优化测点数，运用模糊聚类方法对武汉城区４８个网格测点的ＴＳＰ、ＳＯ２污染强度置信水平进行聚类；运用日均值和百分位数逼近方法检验；结合优化布点原则等，最终确定的ＴＳＰ、ＳＯ２的５个优化测点能集中反映城区大气环境中ＴＳＰ、ＳＯ２的总体污染水平。     

反相高效液相色谱法测定污水中壬基酚聚氧乙烯醚总量

建立了固相萃取一反相液相色谱一荧光检测法分析污水中壬基酚聚氧乙烯醚总量的方法.固相萃取采用Wa-ters Oasis HLB固相萃取柱(30 μg×60 mg×3 mL),6 mL二氯甲烷/甲醇(90/10,V/V)混合溶剂洗脱,洗脱液用氮吹仪浓缩至1 mL,回收率为99.68%.采用ZORBAX Eclipse XDBC-18(4.6 mm×150 mm,5 μm)反相色谱柱,甲醇/水为流动相,流速1.0 mL/min,以每分钟增加2.5%的梯度陡度进行洗脱,流动相中甲醇比例由70%增加到100%,柱温23℃,进样量15μL.荧光检测器的激发波长230 nm,发射波长313 nm.采用外标法定量.该方法的空白加标和污水样品加标回收率均在90%以上,标准偏差小于10%,定量下限为0.97～1.90 μg/L.利用该方法分别对污水处理厂进水水样、二级处理出水水样、再生水水样进行了测定,测定结果的准确度和精密度满足痕量分析的要求.     

Sustainable water–energy–environment nexus

Environmental Science and Pollution Research -