Optimizing electron spin resonance detection of hydroxyl radical in water

The parameters affecting the electron spin resonance (ESR) detection of hydroxyl free radical in water are studied and optimized. The hydroxyl radical is generated by the Fenton reaction with iron (II) ammonium sulfate and hydrogen peroxide reacting in a phosphate buffer using N-tert-butyl-alpha-phenylnitron as the spin trap. The concentrations of Fe²⁺, H₂O₂, and phosphate buffer are the parameters studied. The Taguchi method and the orthogonal experiment design were used to evaluate the effects of these parameters on the ESR signal intensity. By the analysis of the signal-to-noise ratio and the analysis of variance, the order of importance of the various parameters on the hydroxyl radical formation is determined for optimal ESR detection of hydroxyl radical. The results will help the development of water purification technologies using hydroxyl free radical as a green oxidant.     

The influence of untreated wastewater to aquatic communities in the Balatuin River,The Philippines

A risk assessment of chemical constituents in rivers that receive untreated wastewater should take into account the adverse effects of increased biological oxygen demand (BOD), ammonia and reduced dissolved oxygen (DO). This concept was tested via a field study in the Balatuin River, The Philippines, where the influence of physical and chemical factors, including the consumer product chemical linear alkylbenezene sulfonate (LAS), to aquatic communities (algae, invertebrates, fish) was determined. Periphytic algae were found to be insensitive to high BOD (>10 mg/l) and ammonia (>0.01 mg unionized NH(3)/l), concentrations from organically enriched untreated wastewater discharges. However, taxa richness and abundance of macroinvertebrates were influenced greatly by the discharges. Where BOD and ammonia concentrations were elevated, the dominant taxa were oligochaete worms and chironominds. Fish and crustaceans (freshwater crabs and prawns) were found only in sites with the least BOD concentrations (furthest upstream and downstream). The maximum concentration of LAS (0.122 mg/l) was less than that expected to affect 5% of taxa (0.245 mg/l), whereas exceedences of DO and ammonia criteria were observed in several sites. The lack of recovery observed was attributed to influences of low DO, high ammonia and poor colonization from upstream and downstream reaches due to organically-enriched discharges     

微生物抗重金属毒性研究进展

不少重金属是微生物正常生长的必需元素 ,但是当重金属在菌体内浓度过高时 ,会对菌体产生毒性。微生物可通过细胞的表面富集与细胞膜成分的改变减小毒性的破坏 ,在重金属进一步的诱导下 ,菌体会产生由结构基因与调节基因组成的抗性基因 ,通过多途径的联合作用对重金属的毒性进行解毒     

一种新型环境矿物材料在废水处理中的应用研究

实验研究表明 ,磷矿石作为一种新型环境矿物材料对重金属离子工业废水具有较好的处理效果 ,且自身具有显著的优点。采用分级处理的方法以及磷矿石的合适用量可以使处理后的工业废水达到排放标准甚至饮用标准 ,同时 ,由于磷矿石去除重金属离子速度快 ,在瞬间即可发生作用 ,使得利用动态法进行工业废水的连续处理成为可能 ,而且不会产生二次污染 ,具有工艺应用意义     

反硝化除磷的影响特性试验

采用SBR反应器（厌氧/缺氧/好氧工艺）,分别研究了乙酸盐及硝酸盐浓度变化对反硝化除磷的影响特性.试验结果表明,当进水COD浓度＞230 mg/L时,乙酸盐浓度的变化对释磷、除磷速率等影响并不显著.在硝酸盐浓度＜30 mg/L时,硝酸盐浓度越高,缺氧段除磷速率也就越高.在C/P＞23,C/N＞5条件下,SBR系统对磷、氮去除率在90%以上.     

水处理工艺去除藻毒素的效果探讨

探讨了饮用水处理的各工艺过程对藻毒素的去除作用,并根据前期已进行的实验对各工艺的优化组合进行了讨论,认为以气浮代替沉淀,并附之以粉末活性炭吸附预处理可有效地去除藻毒素;对没有条件改造沉淀池的水厂可暂时采用预氯化和粉末活性炭吸附组合的工艺也可达到较好的效果;对生物预处理工艺进行适当的强化,可达到对有机物、藻类、藻毒素等物质的有效去除.     

固相微萃取气相色谱法测定水样中的苯胺、吡啶

应用PDMS/DVB固相微萃取探头,结合GC/FID测定水中的苯胺、吡啶.优化了萃取温度、萃取平衡时间、pH等条件.该方法对苯胺和吡啶的检测限分别为0.050、0.065 mg/L,相对标准偏差6.44%～8.67%,具有快速、准确和方便等优点.     

建筑陶瓷行业SO2污染物评价及总量控制实用方法

采用高斯点源模型对建陶生产造成的SO2地面浓度增量进行计算.利用比例下降模型计算建陶业的SO2允许排放总量,并根据企业的设备生产能力进行了总量分配,在方法上具有较强的可操作性,计算结果表明,可有效降低所在地区的SO2地面浓度.     

秸秆固定化石油降解菌降解原油的初步研究

用秸秆做载体固定嗜碱芽孢杆菌(Bacillus alcalophilus SG)降解原油,其原油去除率为73.88%,高于单纯投加菌液或者菌液与秸秆的混合物的原油去除率.秸秆的最佳投加量(干重)为25.0 g/L,最佳固定化时间为30 h.用预处理过的秸秆固定SG,降低了固定化SG的原油去除率.在固定化培养基中添加无机盐离子,促进了固定化SG对原油的降解.不同初始pH的原油培养基在固定化SG降解原油的过程中逐渐呈中性或偏碱性.固定化SG在pH 6.0～10.0时对原油均有不错的降粘能力.     

污泥的粘度与浓度、温度三者关系式的实验推导

通过融合污泥粘度与污泥浓度关系式、污泥粘度与温度关系式,得到一个新的关系式:污泥粘度与污泥浓度、温度的关系式,并通过实验数据拟合出各项参数,拟合效果比较理想.得出的污泥粘度与污泥浓度、温度的关系式对了解污泥的粘度变化非常有帮助,同时,该关系式也将为污泥处理、处置方案的制定提供参考依据.