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.     

Application of geographic information system technique and analytical hierarchy process model for land-use suitability analysis on coastal area

Land-use suitability is the ability of a given type of land to support a defined use. GIS is known as a powerful tool for handling spatial data in land-use analysis. Application of this tool alone cannot overcome the lack of consistency in opinions given by experts when trying to assign relative importance to each of the several criteria considered in a suitability analysis. The combination of GIS and Multi-Criteria Decision Analysis (MCDA) is a powerful approach used to assess land suitability. To address this issue, the Analytical Hierarchy Process method is used in combination with the GIS tool. The aim of this study is to demonstrate how GIS tools and AHP model can be used for integrated coastal resource planning and management. Based on the information from final map/suitability map, we can define the best area. The findings indicate that the area 1 (2111 m) from class 3 is the most appropriate one because it has good facilities and wide open areas. This study indicates how the integrated tool is handled effectively in a land use suitability analysis for building hotels in the coastal areas of Terengganu in Malaysia. This research develops a framework for integrating GIS and AHP to incorporate the decision maker’s preferences on a range of factors in finding land areas suitable for coastal development.     

城市污水一级强化处理工艺——高负荷生物吸附再生法的应用研究

根据理论分析提出生物吸附-沉淀-再生的城市污水处理工艺，即高负荷生物吸附再生法。该工艺对污染物去除的作用主要包括污泥的絮凝作用、吸附作用和生物代谢作用，而以前两者的作用为主。对城市污水的生产性试验研究结果表明，该工艺能够较大程度地提高SS、COD、SCOD和BOD等污染物的去除率，具有明显的处理效果，对于西北干旱缺水地区实现污水资源化是切实可行的方法。     

环境规划中的非线性特征

 在实际环境规划中,很少考虑到非线性特征对环境投入的效益影响.以国内外目前主要3类水环境规划为例,研究了环境投入与环境改善之间的关系.对每一类环境规划,环境改善均随投入的增加而迅速减少.由于传统的环境管理或规划在选择下一种措施之前总是将大部分费用投入到前一种措施中,因此传统的环境管理或规划忽略了环境系统有关的非线性特征.应将有关费用投入以保证下一步措施获得最大的环境改善.与传统的环境管理或规划相比,这种考虑环境系统有关非线性特征影响的投入策略可以达到用较少的经费获得迅速的环境改善.     

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.     

香根草和黑麦草对重金属铅的生理响应及累积性研究

以香根草(Vetiveria zizanioides)和黑麦草(Lolium perenne)为材料,通过水培研究了0,5,10,50,200,500 mg/L铅处理对两种植物生长、生物量的影响及铅在植物根、茎叶中的累积特征,结果表明,(1)铅浓度10 mg/L以下,香根草和黑麦草能够正常生长;铅浓度为5 mg/L条件...     

再生水中硫酸盐还原菌对Q235碳钢的腐蚀行为

再生水回用是缓解我国水资源危机的有效途径。然而由于再生水营养丰富,微生物大量繁殖成为其回用的关键问题。从以再生水作为补充水源的3倍循环冷却水中分离纯化出硫酸盐还原菌(SRB),在实验室条件下,采用环境扫描电镜(SEM)、原子力显微镜(AFM)、线性极化电阻、极化曲线、电化学阻抗谱(EIS)等方法研究了SRB对Q235碳钢的腐蚀行为。结果表明,浸泡初期SRB生物膜抑制碳钢的腐蚀,随后促进碳钢的腐蚀,表现为点蚀,随着浸泡时间的延长,腐蚀速率逐渐下降并趋于稳定,但碳钢表面的粗糙度和腐蚀坑深却逐渐增大。7 d时碳钢表面形成完整的生物膜,随后扩散作用成为电极反应控制的主导。     

天然超细针状羽绒粒子对染料的吸附性能

采用超细粉体加工设备制备了天然超细针状羽绒粒子,考察其对模拟染料废水溶液中酸性大红3R、直接耐酸大红4BS、还原大红R的吸附性能,探讨了pH、吸附剂用量等因素对染料吸附的影响。实验结果表明,超细羽绒粒子是一种针状介孔吸附材料,具有连续的孔径分布和发达的孔结构。染料溶液pH为3.0,超细羽绒粒子用量5 g/L时吸附效果最好。对吸附数据进行Langmuir、Freundlich、Tempkin以及D-R吸附模型线性拟合,得出超细羽绒粒子对3种染料的吸附规律最符合Langmuir等温吸附方程,其理论最大吸附容量分别为137.55、108.11和87.72 mg/g。对吸附能计算发现,超细羽绒粒子对酸性大红3R、直接耐酸大红4BS以及还原大红R的吸附是化学吸附过程。研究表明,超细羽绒粒子是一种最具有应用潜力的吸附印染废水中有毒有机染料的高效吸附剂。     

Interaction of As and Sb in the hyperaccumulator <Emphasis Type="Italic">Pteris vittata</Emphasis> L.: changes in As and Sb speciation by XANES

Arsenic (As) and antimony (Sb) are chemical analogs that display similar characteristics in the environment. The As hyperaccumulator Pteris vittata L. is a potential As–Sb co-accumulating species. However, when this plant is exposed to different As and Sb speciation, the associated accumulating mechanisms and subsequent assimilation processes of As and Sb remain unclear. A 2-week hydroponic experiment was conducted by exposing P. vittata to single AsIII, AsV, SbIII, and SbV or the co-existence of AsIII and SbIII and AsV and SbV. P. vittata could co-accumulate As and Sb in the pinna (>1000 mg kg^?1) with high translocation (>1) of As and Sb from the root to the pinna. P. vittata displayed apparent preference to the trivalent speciation of As and Sb than to the pentavalent speciation. Under the single exposure of AsIII or SbIII, the pinna concentration of As and Sb was 84 and 765 % higher than that under the single exposure of AsV or SbV, respectively. Despite the provided As speciation, the main speciation of As in the root was AsV, whereas the main speciation of As in the pinna was AsIII. The Sb in the roots comprised SbV and SbIII when exposed to SbV but was exclusively SbIII when exposed to SbIII. The Sb in the pinna was a mixture of SbV and SbIII regardless of the provided Sb speciation. Compared with the single exposure of As, the co-existence of As and Sb increased the As concentration in the pinna of P. vittata by 50–66 %, accompanied by a significant increase in the AsIII percentage in the root. Compared with the single exposure of Sb, the co-existence of Sb and As also increased the Sb concentration in the pinna by 51–100 %, but no significant change in Sb speciation was found in P. vittata.     

火山石生物滤床对微囊藻毒素的去除

微囊藻水华爆发导致大量微囊藻毒素释放至地表水环境中,严重威胁着饮用水供水安全.通过不同条件火山石自然曝气生物滤床(活性挂膜、灭活挂膜、未挂膜和无填料滤床)对不同形态、构型(MC-LR、MC-RR)的微囊藻毒素的去除实验,探讨其去除效率、途径和机理.结果表明,火山石自然曝气生物滤床对微囊藻毒素的去除是微生物降解和基质吸附共同作用的结果.胞外毒素和胞内毒素的总去除率分别为58%和91%.其中,胞外毒素主要通过微生物降解作用途径去除,占胞外毒素总去除率的(41±4.2)%,胞内毒素则主要通过基质吸附途径去除,占胞内毒素总去除率的(64±5.1)%.生物膜吸附、光降解等其他途径无明显作用.另外,不同构型的微囊藻毒素在火山石自然曝气生物滤床中均能有效去除,MC-LR和MC-RR的去除率分别为68%和54%.