改良倒置A2/O工艺设计

在目前广泛采用的AO、A2O、倒置A2O等工艺的基础上,为提高脱氮除磷效率,提出改良倒置A2O工艺。并对其工艺的特点、设计和脱氮除磷效率进行了详细的研究和分析。     

土地利用/覆盖变化对长江上游非点源污染影响研究

在国内外相关研究的基础上,利用输出系数模型,结合RS和GIS技术,对长江上游的非点源污染负荷进行了空间模拟和负荷估算.模拟结果表明,在不考虑流域损失的前提下,由于土地利用造成的非点源污染负荷TN总量从20世纪70年代的123万t下降至2000年的116万t,基本呈逐年减少的趋势,由土地利用造成的TP的变化趋势与TN基本相同,从70年代的3.7万t下降到2000年的3.5万t左右.就省份、土地利用类型和水系而言,四川省、种植用地和草地以及金沙江水系和嘉陵江水系对长江上游的非点源污染贡献较大.在非点源污染负荷强度上,重庆市和嘉陵江水系单位面积负荷最高,是今后应重点治理的地区.结果表明,该模型可以对长江上游这样的超大尺度空间的非点源污染进行较好的空间模拟.     

光电催化降解壬基酚影响因素研究

采用sol-gel法制备TiO2薄膜光电极,以该电极为工作电极,铂丝作对电极,饱和甘汞电极为参比电极,对壬基酚的光电催化降解进行了研究。结果表明:该电极具有n型半导体的特征行为。在外加偏压为+0.8V、pH=5、、30mg/L的H2O2中对初始浓度为20mg/L的壬基酚溶液光照180min降解率达62.22%。讨论了氧的存在、外加偏压、pH等因素对光电催化反应的影响。     

层状氢氧化镁铝对偶氮染料酸性黑10B的脱色性能研究

分别用层状氢氧化镁铝(LDH)和焙烧层状氢氧化镁铝(CLDH)作为吸附剂吸附脱除水溶液中偶氮染料酸性黑10B.考察了脱色时间、pH值、吸附剂的投加量、温度、染料初始浓度和焙烧温度等因素对脱色率的影响.结果表明,LDH及CLDH对酸性黑10B染料具有良好的脱除效果,室温下,10g/L LDH和1g/L的CLDH对浓度为100mg/L的染料的脱色率分别达95.93%和99.97%.pH值是影响吸附能力的关键因素,吸附剂对溶液pH值有一定缓冲作用.LDH及CLDH对酸性黑10B吸附结果符合Langmuir吸附等温式.饱和吸附后的LDH及CLDH用高温热解法再生,吸附性能良好,随再生次数增多,脱色率下降.     

Effect of humic substances on the precipitation of calcium phosphate

For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate （as P） and 20 mg/L HS （as dissolved organic carbon, DOC） at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium （Ca） and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction （XRD） and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite （HAP） by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.     

高效液相色谱串联质谱法测定某市污水处理厂进出水中的全氟化合物

通过建立直接进样-高效液相色谱串联质谱（HPLC-MS/MS）测定污水处理厂进出水中的10种全氟化合物的方法,了解污水厂进出水中全氟化合物污染情况。10种目标分析物在10~500 ng/L范围内具有良好的线性关系,方法检出限为2.3~8.3 ng/L,精密度为2.1%~7.1%,加标回收率为60.6%~91.7%。应用该方法测定某市典型污水厂进出水中的全氟化合物,进水中全氟化合物质量浓度为90.9~206 ng/L,主要污染物是PFOA、PFHxS和PFBS;出水中全氟化合物的质量浓度为67.4~158 ng/L,环境排放量为6.7~22.9 g/d,主要污染物是PFOA和PFHxS。结果表明,该方法能很好地适用于复杂基质中10种全氟化合物的检测。     

固相萃取-超高效液相色谱/三重四极杆质谱法同时测定地表水中8种亚硝胺类化合物

建立了固相萃取（SPE）-超高效液相色谱/三重四极杆串联质谱（UPLC-MS/MS）同时测定地表水中8种亚硝胺类化合物的方法。水样中目标物经椰壳活性炭固相萃取小柱吸附富集,小柱经氮气吹干后采用二氯甲烷洗脱。待测样品采用Atlantis T₃柱,以水-甲醇作为流动相进行梯度洗脱,大气压力化学电离源（APCI）正离子模式多反应监测方式（MRM）进行检测,内标法定量分析。8种目标物在相关线性范围内线性良好(r≥0.9950),地表水加标回收率为55.4%~90.4%,相对标准偏差为3.1%~14.3%,方法检出限为1.1 ~1.8 ng/L。本方法准确度和灵敏度高,适用于快速测定地表水中8种亚硝胺类化合物含量。     

原子吸收法测定土壤中铅的方法

通过湿法消解土壤样品,利用石墨炉原子吸收分光光度法(GAAS)和火焰原子吸收分光光度法(FAAS)测定不同土壤样品中铅的含量,以验证2种方法的有效性并加以对比。实验结果表明:2种方法均满足土壤中铅含量的测定要求,测定的标准土样含量均在标准值的不确定度范围内,GAAS方法测定结果更接近保证值。二者的相对标准偏差(RSD)值均低于1.5%,FAAS方法的精密度更高,且具有快速简单等优势。     

Enhanced triallyl isocyanurate (TAIC) degradation through application of an O3/UV process: Performance optimization and degradation pathways

• UV/O₃ process had higher TAIC mineralization rate than O₃ process. • Four possible degradation pathways were proposed during TAIC degradation. • pH impacted oxidation processes with pH of 9 achieving maximum efficiency. • CO₃^2– negatively impacted TAIC degradation while HCO₃^– not. • Cl^– can be radicals scavenger only at high concentration (over 500 mg/L Cl^–). Triallyl isocyanurate (TAIC, C₁₂H₁₅N₃O₃) has featured in wastewater treatment as a refractory organic compound due to the significant production capability and negative environmental impact. TAIC degradation was enhanced when an ozone(O₃)/ultraviolet(UV) process was applied compared with the application of an independent O₃ process. Although 99% of TAIC could be degraded in 5 min during both processes, the O₃/UV process had a 70%mineralization rate that was much higher than that of the independent O₃ process (9%) in 30 min. Four possible degradation pathways were proposed based on the organic compounds of intermediate products identified during TAIC degradation through the application of independent O₃ and O₃/UV processes. pH impacted both the direct and indirect oxidation processes. Acidic and alkaline conditions preferred direct and indirect reactions respectively, with a pH of 9 achieving maximum Total Organic Carbon (TOC) removal. Both CO₃^2– and HCO₃^– decreased TOC removal, however only CO₃^2– negatively impacted TAIC degradation. Effects of Cl^– as a radical scavenger became more marked only at high concentrations (over 500 mg/L Cl^–). Particulate and suspended matter could hinder the transmission of ultraviolet light and reduce the production of HO· accordingly.