高浓度氨氮对IC厌氧反应器运行的抑制性研究

在中温(35±1)℃条件下,以葡萄糖为有机碳源,研究氨氮对IC厌氧反应器运行的影响.实验结果表明,氨氮浓度超过3 036 mg/L时对反应器的运行有抑制作用,随着氨氮浓度的增加,抑制作用更加明显,氨氮对系统的IC50为4 500 mg/L;系统运行过程中VFA低于400 mg/L,pH值和碱度分别维持在7.21～7.62之间和2 356～3 065 mg/L之间;反应器对氨氮的平均去除率为12.67%.在毒性恢复实验中,7 d后COD去除率恢复到93.01%;恢复期系统VFA逐渐降低,从第6 d开始维持在152～162 mg/L之间;出水碱度和pH值维持在1 769～2 298 mg/L和7.09～7.27之间,系统运行稳定.     

广东省典型电子工业企业挥发性有机物排放特征研究

针对广东省电子工业进行调研与监测,分别选取了手机、相机及笔记本电脑3类典型产品的代表性企业为研究对象,利用活性炭管采样,样品经溶剂解吸后采用GC/MS分析,获得了排气筒及车间废气的VOCs含量水平及组分特征,并利用监测计算法、排放因子法及物料衡算法3种方式计算了各企业的VOCs排放量.结果表明:喷涂车间VOCs浓度范围为43.01~322.34 mg·m~(-3),调漆、供漆车间VOCs浓度范围为103~172.714 mg·m~(-3);车间中VOCs物种为8~10种,不同产品类型VOCs物种不同,但含氧VOCs的比例均超过50%.排气筒的VOCs浓度范围为48.01~155.38 mg·m~(-3),且不同产品排气筒的VOCs物种均比车间成分简单.3种方式计算的VOCs排放量不同,其中,物料衡算法计算结果最大,监测计算法计算结果最小.3类产品喷涂车间非致癌风险危害商值(HQ)在3.44×10-3~7.17之间,总危害商值之和(HI)分别为2.22×10-2、1.97及7.27.     

Nitrogen and phosphorus removal in an airlift intermittent circulation membrane bioreactor

A new airlift intermittent circulation integrated bioreactor was developed for simultaneous nitrogen and phosphorus removal of wastewater, in which, circulation of mixed liquid between mixing zone and aeration zone was realized by aeration power, alternately anaerobic/anoxic bio-environment in mixing zone was realized by intermittent circulation and simultaneous nitrogen and phosphorus removal was obtained through strengthened denitrifying phosphorus removal process. Removal performance of the reactor was investigated and pollutant removal and transfer mechanism in one operation circle was analyzed. The experiment results indicated that under the influent condition of chemical oxygen demand (COD) concentration of 642.1 mg/L, total nitrogen (TN) of 87.4 mg/L and PO₄^3?-P of 12.1 mg/L, average removal efficiencies of COD, TN and PO₄^3?-P reached 96.4%, 83.2% and 90.5%, respectively, with the hydraulic residence time of 22 hr and operation circle time of 185 min. Track studies indicated that the separation of aeration and mixing zones and intermittent circulation of mixed liquid between the two zones provided distinct biological environments spatially and temporally, which ensured the occurrence of multifunctional microbial reactions.     

巢湖沉积物重金属污染生态风险评价及来源解析

为掌握巢湖沉积物中重金属污染现状并定量解析其来源,采用定点采样的方法获得了巢湖沉积物2015～2017年Cu、Zn、Pb、Ni、Cr、Cd、As、Hg等重金属数据,使用反距离加权插值法和风险评价编码法研究了上述重金属的空间分布特征及潜在生态风险,并应用PMF模型解析了其重金属来源,结果表明:巢湖沉积物中As三年含量均值超过了GB15618中规定的碱性水田土壤风险筛选值,而Zn生物可利用形态占比高,生态潜在风险大;巢湖沉积物中各类金属的空间分布与周边交通线位置相契合,主要表现出东西高中部低的状态,巢湖沉积物中总重金属主要来自交通源(43%)、自然源(27%)、农业源(18%)、工业源(12%),交通源贡献最大、自然源占比高于农业源和工业源,表明当前巢湖正处于城市化初始阶段,其重金属污染水平较低。但随着城市化规模的扩大及程度的加深,巢湖沉积物中重金属污染存在逐年加剧的风险。     

底层磷石膏粉刷石膏的性能研究

首先研究了磷石膏复合材料(PSC)的碳化性能,复配特种化纤改善PSC碳化后的体积安定性,系统地研究PSC固化体和PSC粉刷石膏的力学性能、性膨胀率、水化产物和断面形貌,以期推广底层粉刷PSC石膏在建筑领域的利用。结果表明:PSC内层的AFt衍射峰随着养护龄期的延长呈增加趋势,即AFt含量增加;而PSC外层的AFt衍射峰随着养护龄期的延长呈减少趋势,表明AFt与空气中CO2反应生成CaCO3;化纤质量掺量在0.3%时各项性能优异,365d抗压强度、抗折强度和抗冲击功(46.2 MPa、6.4 MPa和1211J/m2)分别较28d指标减小了5.0%、15.6%和0.2%;PSC耐水性性能优异,但容易受到潮湿空气中CO2的碳化腐蚀,使其力学性能降低,而底层PSC粉刷石膏很少接触到潮湿空气中的CO2,具有较大的利用价值。     

氮输入对纳帕海沼泽湿地土壤氨挥发和反硝化的影响

选取纳帕海常见湿地植物茭草（Zizania caduciflora）和水葱（Scirpus validus）]及其生长土壤为对象,通过培养实验,研究了3个不同氮输入水平[0g-m^2（对照,NO）、20g-m^2（N20）、40g-m^2。（N40）]对茭草和水葱湿地土壤氨挥发和反硝化的影响。结果表明：氮输入促进了茭草和水葱湿地土壤氨挥发化作用,增加了湿地土壤氨挥发的累积量。适量的氮输入对湿地土壤氨挥发促进显著。在培养前期适量氮输入下的氨挥发积累量高于高水平氮输入的,随着培养时间的延长,后期适量氮输入下的积累量明显下降;而高水半氮输入处理下氨挥发积累量的明显增加,适量氮输入下茭草氨挥发积累大于水葱。氮输入增强了菱草和水葱湿地土壤反硝化作用,加快了反硝化N2O的排放。适量的氮输入促进茭草反硝化作用和反硝化损失量增加明显,培养的前期的适量氮输入处理下的反硝化作用和反硝化N2O的排放增强不明显,随着培养时间的延长,高水平氮输入处理下的反硝化损失量越明显,并且水葱较茭草更为明显。后期适量氮输入下的反硝化损失速率和反硝化损失量高于高水平氮输入,适量氮输入较高水平氮输人促进明显,高水平的氮输入限制了反硝化损失,反硝化N2O的排放总量下降,土壤中氮富集增大。     

杭州秋冬季PM2.5污染特征分析

为研究杭州PM_2.5污染来源特征,利用2013—2019年杭州市PM_2.5监测数据和气象观测数据,分析了杭州市2013—2019年PM_2.5浓度变化,选取本地积累型和输入型2种PM_2.5污染过程,结合单颗粒气溶胶飞行时间质谱仪（SPAMS）和在线离子色谱数据,探讨杭州市PM_2.5化学组分和污染来源。结果表明：每年秋冬季（11月至次年3月）杭州以东北风、西北风及偏南风为主,风速低于4 m/s时,大气扩散条件差,受本地污染物积累影响,PM_2.5浓度容易出现超标;风速较大且为东北风和西北风时,受上游污染输入影响,易出现PM_2.5重度污染。本地积累型和输入型案例中,PM_2.5化学组分中占比最大的为NO₃^-、SO₄^2-和NH₄⁺;PM_2.5浓度上升过程中,二次NO₃^-和SO₄^2-转换率明显上升,其中NO₃^-上升更为显著,二次气溶胶污染严重。2次案例中,PM_2.5来源贡献占比前3位均为机动车尾气源、燃煤源和工业工艺源,其中本地积累型PM_2.5浓度上升阶段,机动车尾气源占比会明显上升;输入型案例中,输入阶段机动车尾气源占比显著上升,燃煤源贡献也小幅上升。     

不同孔径HZSM-5协同低温等离子体催化降解甲苯性能研究

研究了HZSM-5分子筛孔径对其在等离子体场内催化降解甲苯的影响.采用化学液相沉积法对HZSM-5分子筛进行改性,利用XRD、氮气吸附脱附等方法表征样品的骨架结构和表面性质,并用择形吸附实验对样品孔径进行表征.同时,评价了HZSM-5分子筛体系中降解甲苯的性能,研究了分子筛吸附甲苯性能及臭氧的产量,并采用飞行时间质谱(TOF-MS)和气相色谱-质谱联用仪(GC-MS)分析了反应产生的有机副产物.结果表明:液相沉积法成功调控了HZSM-5孔径,样品孔径随沉积剂用量增加而减小;同时,样品均具有相同的MFI骨架结构,比表面积和孔容相差不大.HZSM-5的孔径尺寸对甲苯去除率影响不大,但对碳平衡有影响,孔径越大,碳平衡越好.孔径较大的HZSM-5分子筛对甲苯具有更大的吸附速率和吸附容量,同时更多臭氧参与反应,生成·OH和O·,促进甲苯深度氧化,减少副产物,提高碳平衡.     

超声波/H_2O_2工艺对活性藏青废水的脱色处理

采用超声波/H2O2工艺对活性藏青模拟废水进行降解,考察了双氧水投加量、废水初始pH值、废水初始浓度、无机阴离子、金属离子等因素对降解效果的影响。结果表明:在pH为2,反应温度为50℃,H2O2投加量为33.3 mg/L,金属离子催化作用下,超声波/H2O2对活性藏青降解率可达92.7%,远远高出单独超声波作用时的降解率8.5%,COD Mn去除率达86.9%。这主要是因为在超声波的空化作用下H2O2会迅速产生·OH自由基增强了氧化降解效果,充分发挥了两者的协同作用。     

A facial strategy to efficiently improve catalytic performance of CoFe2O4 to peroxymonosulfate

Cobalt iron spinel (CoFe₂O₄) has been considered as a good heterogeneous catalysis to peroxymonosulfate (PMS) in the degradation of persistent organic pollutants due to its magnetic properties and good chemical stability. However, its catalytic activity needs to be further improved. Here, a facial strategy, “in-situ substitution”, was adopted to modify CoFe₂O₄ to improve its catalytic performance just by suitably increasing the Co/Fe ratio in synthesis process. Compared with CoFe₂O₄, the newly synthesized Co_1.5Fe_1.5O₄, could not only significantly improve the degradation efficiency of phenol, from 50.69 to 93.6%, but also exhibited more effective mineralization ability and higher PMS utilization. The activation energy advantage for phenol degradation using Co_1.5Fe_1.5O₄ was only 44.2 kJ/mol, much lower than that with CoFe₂O₄ (127.3 kJ/mol). A series of related representations of CoFe₂O₄ and Co_1.5Fe_1.5O₄ were compared to explore the possible reasons for the outstanding catalytic activity of Co_1.5Fe_1.5O₄. Results showed that Co_1.5Fe_1.5O₄ as well represented spinel crystal as CoFe₂O₄ and the excess cobalt just partially replaced the position of iron without changing the original structure. Co_1.5Fe_1.5O₄ had smaller particle size (8.7 nm), larger specific surface area (126.3 m²/g), which was more favorable for exposure of active sites. Apart from the superior physical properties, more importantly, more reactive centers Co (Ⅱ) and surface hydroxyl compounds generated on Co_1.5Fe_1.5O₄, which might be the major reason. Furthermore, Co_1.5Fe_1.5O₄ behaved good paramagnetism, wide range of pH suitability and strong resistance to salt interference, making it a new prospect in environmental application.