磁絮凝处理废水工艺条件的响应曲面法优化研究

以聚硅硫酸铁(PFSS)为絮凝剂、磁流体为磁种,采用磁絮凝法处理模拟废水。在正交实验基础上,利用Matlab软件进行响应曲面分析,研究磁絮凝法处理模拟废水的各因素间具有的交互作用关系。回归拟合结果表明最佳工艺条件为:PFSS加入量36.8g/L,模拟废水pH7.4,磁种加入量14.7mg/L,搅拌转速266r/min。在最佳工艺条件下进行实验,TP去除率为97.70%。     

活性炭电极对溶液中NaCl的电吸附行为

用活性炭、酚醛树脂和乌洛托品制备了活性炭电极。利用扫描电子显微镜(SEM)、傅立叶变换红外光谱仪(FTIR)分析了电极的表面性质,发现电极表面的黏结剂可完全碳化,且活性炭上带有大量含氧官能团;利用电化学工作站采用循环伏安法对电极进行了测试,表明电吸附是一稳定而又可逆的过程,电极电流的最大值由碳化前的0.019 8A升至碳化后的0.042 7A,双电层电容提高到碳化前的2.16倍;对NaCl的电吸附实验表明碳化后电极的电吸附率是碳化前的1.59倍,活性炭的吸附容量也由1.14mg/g提高到3.29mg/g,且活性炭电极具有良好的重复利用性。     

膨润土接枝丙烯酸高吸水性树脂的抑尘性能研究

在微波辐射下制备了膨润土接枝丙烯酸高吸水性树脂(SAP)(一种加入聚乙烯醇(PVA),另一种不加入PVA)。结果表明:(1)红外光谱图表明,PVA与聚合网络形成了半互穿网络结构;X射线衍射图表明,膨润土与PVA、丙烯酸形成了具有无定形结构的复合产物。(2)不论是沙土堆还是尘土堆,喷洒膨润土接枝丙烯酸SAP溶液的抑尘效果明显比喷洒自来水好;喷洒膨润土接枝丙烯酸SAP溶液的尘土堆的抑尘效果好于沙土堆。(3)在温度为15℃时,考虑到节约成本的问题,首选不加入PVA的膨润土接枝丙烯酸SAP做抑尘剂;在温度为45℃时,加入PVA的膨润土接枝丙烯酸SAP适合做抑尘剂。(4)膨润土接枝丙烯酸SAP浓度越高,其耐蒸发性越高。     

小型燃油锅炉NOx的排放特征与管理控制

以68台燃油锅炉（≤10～MW）NOx排放实测数据为基础,通过统计分析方法,研究了NOx的排放特征;通过对比分析,探讨了我国燃油锅炉NOx排放控制与管理现状,讨论了进一步加强我国燃油锅炉NOx排放管理控制的可能性与可行性,并提出了相应的管理控制建议。结果表明,NOx平均排放浓度为318．2mg／m^3,基于燃料消耗量的平均排放因子为4．4kg／t,基于燃料发热量的平均排放因子为102．8ng／J,基于燃料氮含量的平均排放因子为2．1mg／mg;建议采取分阶段控制的方式,逐步提高NOx排放限制,从而实现控源减排目标。     

Using Si depletion in aerosol to identify the sources of crustal dust in two Chinese megacities

Depletion of Si in transported dust has been recognized for many years. It can be used to distinguish between transported and local dust in cities, although it rarely has been. Here we use the variations of the Si/Al ratio in 15 months of continuous PM_2.5 samples at Beijing (northern China) and Chongqing (southwestern China) to reveal the seasonal patterns of their dust sources. For both cities, peaks of concentration for Si and Al in PM_2.5 corresponded with minima of Si/Al, and could often be linked to pulsed air flow from deserts to the northwest. With significant depletion (up to 80%) and homogeneous distribution at urban and rural sites, Si/Al showed a clear seasonal evolution, which decreased from spring to summer, increased from fall to winter, and collapsed during Chinese Spring Festival, indicating the dominance of transported dust, local fugitive dust and firework influence, respectively. The low ratios implied that desert dust is a common source during spring at Chongqing, whereas its presence during cold season at Beijing was also more frequent than expected. Failing to recognize the depletion of Si may lead to an overestimate of desert dust by 15%–65% when using the average abundance of Al in crust (6%–8%), as in previous studies. The difference in Si/Al ratio between local and transported dust implies that >60% of the dust at Beijing came from outside the city during the springs of 2004–2006. This result can help resolve the contradictory findings on this topic that have been presented earlier.     

新型SBBR处理畜禽废水脱氮实验研究

以畜禽废水为处理对象,将序批式运行模式应用到好氧三相内循环生物流化床中,考察在不同模式下的处理效果及氮的转化情况。实验结果表明,在室温条件下,进水COD浓度为2 000 mg/L左右,总氮为140 mg/L左右时,保持溶解氧在2~2.5 mg/L,交替好氧/缺氧运行方式处理效果优于单一的好氧/缺氧方式;模式为3 h(曝气)-1.5 h(停曝)-1.5 h(曝气)-1 h(停曝)时系统对总氮和氨氮处理效果最好,总氮去除率达到90%,系统主要脱氮方式为同步硝化反硝化和短程硝化反硝化。     

Selective removal of Cr(VI) from aqueous solution by adsorption on mangosteen peel

Mangosteen peel, rich in polyphenolic compounds, was used to prepare the adsorbent exhibiting highly selective adsorption for Cr(VI) over other metal ions such as Pb²⁺, Fe³⁺, Zn²⁺, Cd²⁺, and Cr³⁺ at the pH values of 1～4. The chemical modification method proposed by using calcium hydroxide is quite cost-effective and ecofriendly without using any toxic reagents or causing any secondary pollution. The adsorption isotherm results revealed that the adsorption of Cr(VI) on the gel fit well the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) at pH levels 1, 2, 3, and 4 was evaluated to be 2.46, 2.44, 1.99, and 2.14 mol/kg, respectively. The adsorption mechanism for Cr(VI) on the saponified gel was verified to follow an esterifiaction reaction coupled with the reduction of Cr(VI) to Cr(III) in which H⁺ plays a role of promoter. Thus, modified mangosteen peel gel has the prominent selectivity and low cost for Cr(VI) removal.     

连片生态浮床对微污染河水的净化效果

选取漕桥河的支流庙尖浜作为实验河段,以睡莲(Nymphaea alba)、菖蒲(Acorus calamus Linn)和水芹(Oenan-the javanica(Blume)DC)作为微污染水体净化的浮床植物,研究连片生态浮床的净化能力随季节的变化和浮床面积对连片生态浮床净化能力的影响。结果显示,秋-冬-春季节内植物的净化能力随季节变化呈"U"型,相应的河水水质的变化呈一个倒置的"U"型;在一定营养负荷和植物正常生长状况下,沿水流方向,氮、磷含量随浮床面积的增加而降低——春季时,随浮床面积增加,菖蒲区对TN的去除率由8.6%增加到26.7%,TP的去除率由17.1%增加到58.2%,水芹区对TN和TP的去除率最高可达22.0%和28.0%。研究表明连片生态浮床是河道水质改善的有效可行的方法之一,可为太湖入湖河流的营养物质控制提供科学依据。     

HZ-16型大孔树脂吸附处理含RDT-8废水

采用HZ-16型大孔树脂对含三（三溴苯氧基）三嗪（RDT-8）废水进行吸附及脱附处理。实验结果表明：在废水流量为4.0 BV/h的条件下,树脂最佳吸附工艺条件为出水体积88.0 BV,此条件下出水COD小于291 mg/L,挥发酚质量浓度小于0.08 mg/L;在脱附液流量为0.5 BV/h的条件下,树脂最佳脱附工艺条件为脱附液体积3.0 BV,此条件下脱附液中挥发酚质量浓度为30.6 mg/L,挥发酚脱附率高达76.4%。在最佳吸附-脱附工艺条件下,连续进行10次动态吸附-脱附实验,吸附出水中COD为137~294 mg/L,COD去除率为72.5%~89.1%,挥发酚质量浓度稳定在0.05 mg/L以下,挥发酚去除率为99.8%~100%,说明HZ-16型大孔树脂的吸附-脱附性能稳定。     

A review of mechanochemistry applications in waste management

Mechanochemistry is defined to describe the chemical and physicochemical transformation of substances during the aggregation caused by the mechanical energy. Mechanochemical technology has several advantages, such as simple process, ecological safety and the possibility of obtaining a product in the metastable state. It potentially has a prospective application in pollution remediation and waste management. Therefore, this paper aims to give an overall review of the mechanochemistry applications in waste management and the related mechanisms. Based on our study, the modification of fly ash and asbestos-containing wastes (ACWs) can be achieved by mechanochemical technology. Waste metal oxides can be transformed into easily recyclable sulfide by mechanochemical sulfidization. Besides, the waste plastics and rubbers, which are usually very difficult to be recycled, can also be recycled by mechanochemical technology.