超声-Fenton高级氧化降解染料工业废水的研究

采用超声与Fenton高级氧化技术联合处理染料废水,取得了满意的效果。同时考察了初始浓度、初始pH值、超声时间、超声频率、超声功率、H2O2和FeSO4初始浓度等因素对其COD去除效果的影响,当超声波频率为45 kHz,功率为200 W,初始pH值为2.63,超声时间为150 min,H2O2浓度为60 mmol/L,FeSO4浓度为12 mmol/L时,染料废水COD去除率达到91.8%。     

二价铁活化过硫酸盐降解土壤中十溴联苯醚

研究了Fe~(2+)活化过硫酸钠产生的硫酸根自由基降解土壤中十溴联苯醚(PBDE~(-2)09)的效果,分别考察了Na2S2O8的用量、初始pH值、Na2S2O8与Fe~(2+)摩尔比例、反应时间4个因素对降解效果的影响。通过正交实验确定了降解污染物的最优条件。结果表明,在Na2S2O8用量为0.8 mmol·kg~(-1),初始pH为5,Na2S2O8与Fe~(2+)摩尔比为2∶1,反应时间为30 min的最优条件下,降解率达96.36%。分子探针竞争实验表明体系中产生了硫酸根自由基。Fe~(2+)活化过硫酸钠降解PBDE~(-2)09反应过程符合一级反应动力学。     

一株1，2-二氯苯降解菌的分离鉴定及其降解特性

采用富集驯化方法,从盐城芦苇湿地根际土壤中分离得到一株可高效降解1,2-二氯苯的菌株,命名为DL-1。该菌株可以在以1,2-二氯苯为惟一碳源的无机培养基上生长,能够耐受最高浓度为200 mg/L的1,2-二氯苯。根据形态特征观察、生理生化鉴定和16S rDNA序列同源性分析,该目标菌株被鉴定为蜡质芽孢杆菌（Bacillus cereus）。菌株DL-1对1,2-二氯苯降解性能研究表明,该菌株为一株兼性厌氧菌,其适宜降解浓度、适宜温度、适宜pH值和适宜接种量分别为120mg/L、32℃、7和10%,在适宜降解条件下降解12,-二氯苯4 d其降解率达到80.3%。本实验为利用该菌株降解12,-二氯苯污水的应用提供了理论基础。     

铁炭微电解-Fe~（2＋）/K_2S_2O_8降解甲基橙

针对偶氮类有机物废水具有色度大,难降解的特点,以对二甲基氨基偶氮苯磺酸钠（甲基橙）为模拟研究对象,对水体系中铁炭微电解-Fe2＋/K2S2O8降解甲基橙的方法进行了研究。通过正交实验确定出该方法各因素的影响程度,进一步通过单因素影响实验确定该方法的最佳条件是：铁炭微电解填料、FeSO4和K2S2O8投加量分别为300 g/L、1.3mmol/L和0.7 mmol/L,初始pH值为7.0。在最佳条件下,甲基橙COD和色度去除率分别能达到64.7%和68.2%。     

铁炭微电解-Fe2+/K2S2O8降解甲基橙

针对偶氮类有机物废水具有色度大,难降解的特点,以对二甲基氨基偶氮苯磺酸钠(甲基橙)为模拟研究对象,对水体系中铁炭微电解-Fe2+/K2S2O8降解甲基橙的方法进行了研究。通过正交实验确定出该方法各因素的影响程度,进一步通过单因素影响实验确定该方法的最佳条件是:铁炭微电解填料、FeSO4和K2S2O8投加量分别为300 g/L、1.3mmol/L和0.7 mmol/L,初始pH值为7.0。在最佳条件下,甲基橙COD和色度去除率分别能达到64.7%和68.2%。     

强化UV/Fenton法降解水中苯酚的研究

研究了UV/Fenton法处理含苯酚废水时H2 O2 和FeSO4 加入量及苯酚初始浓度对酚去除效果的影响及C2 O2 -4 对UV/Fenton法的增强效果。 [H2 O2 ]=2 0mmol/L ,[FeSO4 ]=5mmol/L ,反应 2 0min ,苯酚初始浓度为 5 0mg/L时 ,酚去除率达 99%。UV/Fenton体系中引入C2 O2 -4 后可有效提高对紫外和可见光的利用率 ,进而提高了对高浓度苯酚废水去除效果     

Fe~(2+)活化过硫酸钠原位修复氯苯污染地下水

通过建立土槽模型模拟实际污染场地,并采用Na2S2O8为氧化剂、柠檬酸螯合Fe2+为活化剂,研究了氯苯在地下水中的迁移分布规律、原位修复及其对地下水环境的影响。结果表明,氯苯在含水层水平纵向上的迁移作用大于横向迁移;随着时间的增加,地下水中氯苯浓度变化总趋势为先增加后减少并最终趋于稳定;随着迁移距离的增加,氯苯的浓度逐渐降低。柠檬酸螯合Fe2+活化Na2S2O8能够有效修复受氯苯污染的地下水和土壤;持续氧化36 h后,地下水和土壤中氯苯的去除率分别达到82.4%和80.3%。进一步研究发现,氧化处理后,出水的p H值基本稳定在3.5、SO2-4浓度为88.7mg/L,满足地下水Ⅱ类水质标准。     

热活化过硫酸盐氧化修复柴油污染土壤

采用热活化过硫酸盐法,考察了过硫酸盐浓度、温度、水土比和初始pH对柴油污染土壤氧化修复的影响,并分析了其动力学和热力学参数。结果表明,当Na2S2O8摩尔浓度为0.8mmol/g、温度为70℃、水土比为2.0mL/g、初始pH为11.00时,反应72h后的柴油降解率最高,达到77.85%。动力学和热力学分析表明,热活化过硫酸盐氧化降解柴油过程为自发、吸热、熵增的过程,表观活化能为-80.73kJ/mol。     

FeS/K2S2O8去除水体系中的2,4-D

以2,4-二氯苯氧乙酸(2,4-D)为目标污染物,研究了自制FeS与K2S2O8混合体系去除水体中2,4-D的影响因素,实验结果表明,30℃时,初始pH=7,FeS和K2S2O8初始浓度分别为10 g/L和3.33 g/L,反应24 h,对初始浓度为10mg/L的2,4-D去除率可达77%;FeS/K2S2O8体系对2,4-D的去除速率受反应溶液pH影响显著,在pH为中性或弱碱性条件下速率较大,酸性和过碱性条件去除速率均会减小;对比FeS和K2S2O8单独处理目标污染物的去除率,相同时间和条件下FeS/K2S2O8体系对2,4-D的去除率要高于两者单独处理2,4-D时的去除率之和;利用乙醇和叔丁醇为分针探针,采用分针探针竞争实验鉴定证明该体系中产生了SO-4·和·OH。     

超声波/Fenton工艺降解微量邻苯二甲酸二甲酯和壬基酚效能的研究

研究了在超声波、Fenton不同体系中邻苯二甲酸二甲酯(DMP)和壬基酚(NP)的降解效果.通过正交实验得到超声波/Fenton工艺各个因素影响程度的大小为:H2O2投加量＞初始pH＞反应时间＞Fe2+投加量＞超声功率.最后得到降解250mL质量浓度为100 μg/L的DMP的最佳条件:H2 O2投加量为2 mmol/L、Fe2+投加量为0.40 mmol/L、初始pH为3.00、超声功率为1 800W、反应时间为120 min,降解率可达到85.96％;降解250mL质量浓度为100 μg/L的NP的最佳条件:H2O2投加量为4mmol/L、Fe2+投加量为0.50 mmol/L、初始pH为3.00、超声功率为1 800W、反应时间为120 min,降解率可达到78.70％.     

微电解-Fenton深度处理制药废水影响因素与参数控制

采用铁炭微电解-Fenton联合工艺深度处理制药废水生化出水,探讨了初始pH、曝气量、反应时间等因素对微电解出水Fe2+和Fe3+变化规律、COD降解速率以及后续Fenton氧化效果的影响,为优化微电解-Fenton氧化联合工艺提出了微电解间歇加酸的理论。间歇加酸可提高微电解系统中COD降解速率和Fe2+含量,使后续Fenton氧化无需投加FeSO4·7H2O即可达到较好的COD去除效果。结果表明,当初始pH=2.5,曝气量为0.6 m3/h,间歇加酸30 min/次,微电解反应2 h,出水投加1 mL/L的H2O2进行Fenton氧化2 h,COD总去除率可达81.33%;间歇加酸30 min/次可将微电解反应2 h出水Fe2+浓度从50 mg/L提高至151 mg/L,COD降解速率从10.6 mg COD/(L·h)提高至22.2 mg COD/(L·h)。     

微囊化生物流化床处理邻二氯苯废水

采用海藻酸钠—壳聚糖—活性炭(SA-CA-PAC)生物微胶囊包埋优势降解菌用于生物流化床处理邻二氯苯废水。比较了微囊化菌和悬浮菌对废水的降解效果,同时考察了初始浓度、接种量、pH值、温度和曝气量对降解率的影响。结果表明,微囊化菌比悬浮菌拥有更适宜的生长环境,具有更好的pH稳定性和热稳定性。微囊化菌的降解效果优于悬浮菌,处理150 mg/L的邻二氯苯废水的最佳接种量为10%,最适pH为7.5,最适温度为30℃。     

pH dependence of persulfate activation by EDTA/Fe(III) for degradation of trichloroethylene

The ability of free ferrous ion activated persulfate (S₂O₈²⁻) to generate sulfate radicals (SO₄⁻) for the oxidation of trichloroethylene (TCE) is limited by the scavenging of SO₄⁻ with excess Fe²⁺ and a quick conversion of Fe²⁺ to Fe³⁺. This study investigated the applicability of ethylene-diamine-tetra-acetic acid (EDTA) chelated Fe³⁺ in activating persulfate for the destruction of TCE in aqueous phase under pH 3, 7 and 10. Fe³⁺ and EDTA alone did not appreciably degrade persulfate. The presence of TCE in the EDTA/Fe³⁺ activated persulfate system can induce faster persulfate and EDTA degradation due to iron recycling to activate persulfate under a higher pH condition. Increasing the pH leads to increases in pseudo-first-order-rate constants for TCE, S₂O₈²⁻ and EDTA degradations, and Cl generation. Accordingly, the experiments at pH 10 with different EDTA/Fe³⁺ molar ratios indicated that a 1/1 ratio resulted in a remarkably higher degradation rate at the early stage of reaction as compared to results by other ratios. Higher persulfate dosage under the EDTA/Fe³⁺ molar ratio of 1/1 resulted in greater TCE degradation rates. However, increases in persulfate concentration may also lead to an increase in the rate of persulfate consumption.     

US/Zn~0体系降解水中的对硝基苯甲酸

为高效去除水体中的对硝基苯甲酸、开发新型水处理技术,提出以超声与单质锌联用降解水中的对硝基苯甲酸。考察了锌投加量、溶液初始pH、声功率及溶液初始浓度对拟一级反应速率常数(k0US/Zn)的影响,比较了US、Zn0和US/Zn03体系下的降解常数,并对US/Zn0体系的降解机理进行了初探。结果表明,以上4种因素对k0US/Zn均有很大影响,k0US/Zn分别在溶液初始pH为5、声功率为120 W、溶液初始浓度为0.04 mmol/L时达到最大值,且随着锌投加量的增加而增加。超声与单质锌在降解对硝基苯甲酸的过程中存在很好的协同作用,在最优条件下,k0US/Zn=0.052 min-1,分别是单独超声降解及单独锌降解的21.5倍和2.53倍。在联用体系中,主要是依靠OH·氧化及单质锌还原的相互加强来去除对硝基苯甲酸。     

The reductive degradation of 1,1,1-trichloroethane by Fe(0) in a soil slurry system

Most studies on the treatment of chlorinated contaminants by Fe(0) focus on aqueous system tests. However, few is known about the effectiveness of these tests for degrading chlorinated contaminants such as 1,1,1-trichloroethane (TCA) in soil. In this work, the reductive degradation performance of 1,1,1-TCA by Fe(0) was thoroughly investigated in a soil slurry system. The effects of various factors including acid-washed iron, the initial 1,1,1-TCA concentration, Fe(0) dosage, slurry pH, and common constituents in groundwater and soil such as Cl^?, HCO₃ ^?, SO₄ ^2?, and NO₃ ^? anions and humic acid (HA) were evaluated. The experimental results showed that 1,1,1-TCA could be effectively degraded in 12 h for an initial Fe(0) dosage of 10 g L^?1 and a soil/water mass ratio of 1:5. The soil slurry experiments showed two-stage degradation kinetics: a slow reaction in the first stage and a fast reductive degradation of 1,1,1-TCA in the second stage. The reductive degradation of 1,1,1-TCA was expedited as the mass concentration of Fe(0) increased. In addition, high pHs adversely affected the degradation of 1,1,1-TCA over a pH range of 5.4–8.0 and the reductive degradation efficiency decreased with increasing slurry pH. The initial 1,1,1-TCA concentration and the presence of Cl^? and SO₄ ^2? anions had negligible effects. HCO₃ ^? anions had a accelerative effect on 1,1,1-TCA removal, and both NO₃ ^? and HA had inhibitory effects. A Cl^? mass balance showed that the amount of Cl^? ions released into the soil slurry system during the 1,1,1-TCA degradation increased with increasing reaction time, suggesting that the main degradation mechanism of 1,1,1-TCA by Fe(0) in a soil slurry system was reductive dechlorination with 1,1-DCA as the main intermediate. In conclusion, this study provides a theoretical basis for the practical application of the remediation of contaminated sites containing chlorinated solvent.     

纳米零价铁的制备及其去除水中对氯硝基苯的研究

通过FeSO4与KBH4反应,利用液相还原法制备纳米零价铁颗粒(NZVI),用XRD、SEM和BET对其性能进行表征。在常温常压下利用纳米铁还原废水中的对氯硝基苯(p-CNB),探讨了反应条件对还原率的影响。结果表明,制备过程中碱性物质(NaOH)的添加可以明显减小颗粒粒径,增大比表面积,提高纳米铁还原反应的效率。NZVI对于对氯硝基苯有很好的去除效果,NZVI用量、p-CNB初始浓度和pH值均对其去除效率产生影响。在纳米铁投加量为1 g/L,pH=2的条件下,添加NaOH的纳米铁能在120 min内将质量浓度为50 mg/L的对氯硝基苯基本完全降解,降解率为98.8%。此外,还对NZVI还原对氯硝基苯的机理进行了初步探讨。     

掺Al-TiO2改性膨润土去除微污染水中COD和NH4-N

采用掺Al-TiO2作为改性剂制备改性膨润土,考察了微波辐射功率、辐射时间、TiO2改性剂用量、铝盐掺杂量、pH值对微污染水中COD和NH4-N去除效果的影响。实验表明,微波辐射功率为460 W,辐射时间为8 min,TiO2改性剂用量为1.3 mmol/g,铝盐掺杂量为0.2 mmol/g为最佳制备条件。pH值为6.0,改性膨润土投加量为40 mg/L,沉淀时间为30min时,对微污染水中初始浓度15 mg/L的COD和5 mg/L的NH4-N去除率分别达到92%和59%以上。     

Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion

In situ chemical oxidation (ISCO) is a technique used to remediate contaminated soil and groundwater systems. It has been postulated that sodium persulfate (Na2S2O8) can be activated by transition metal ions such as ferrous ion (Fe2+) to produce a powerful oxidant known as the sulfate free radical (SO4-*) with a redox potential of 2.6 V, which can potentially destroy organic contaminants. In this laboratory study persulfate oxidation of dissolved trichloroethylene (TCE) was investigated in aqueous and soil slurry systems under a variety of experimental conditions. A chelating agent (i.e., citric acid) was used in attempt to manipulate the quantity of ferrous ion in solution by providing an appropriate chelate/Fe2+ molar ratio. In an aqueous system a chelate/Fe2+ molar ratio of 1/5 (e.g., S2O8(2)-/chelate/Fe2+/TCE ratio of 20/2/10/1) was found to be the lowest acceptable ratio to maintain sufficient quantities of Fe2+ activator in solution resulting in nearly complete TCE destruction after only 20 min. The availability of Fe2+ appeared to be controlled by adjusting the molar ratio of chelate/Fe2+. In general, high levels of chelated ferrous ion concentrations resulted in faster TCE degradation and more persulfate decomposition. However, if initial ferrous ion contents are relatively low, sufficient quantities of chelate must be provided to ensure the chelation of a greater percentage of the limited ferrous ion present. Citric acid chelated ferrous ion appeared effective for TCE degradation within soil slurries but required longer reaction times. Additionally, the use of citric acid without the addition of supplemental Fe2+ in soil slurries, where the citric acid apparently extracted native metals from the soil, appeared to be somewhat effective at enhancing persulfate oxidation of TCE over extended reaction times. A comparison of different chelating agents revealed that citric acid was the most effective.     

臭氧辅助UV/Fenton法处理电镀添加剂生产废水

采用臭氧辅助光芬顿法处理电镀添加剂生产废水，考察双氧水、FeSO₄·7H₂O、pH和反应时间等因素对废水COD和UV₂₅₄去除的影响。实验结果表明，pH=4，臭氧通入量为0.25 g，双氧水的投加量93.3 mL/L，FeSO₄·7H₂O投加量为5.3 g/L，最佳反应时间为30 min，COD和UV₂₅₄去除率分别达到92.64%和87.95%。这表明，臭氧辅助光芬顿法对电镀添加剂生产废水处理效果显著，处理时间大大减少。