活性炭的筛选及其吸附饮用水中低量溴化物的研究

本文通过研究星光K02活性炭、星光K04活性炭和太西活性炭等六种活性炭对饮用水中低量溴化物的吸附效率,筛选出了吸附效果最佳的太西活性炭。同时探讨了不同的活化方式、不同的吸附时间以及饮用水中不同的p H值对TAC(太西活性炭)吸附饮用水中低量溴化物(7.50μg/L)效率的影响。实验采用了蒸馏水浸泡和稀盐酸浸泡两种活化方式,用CO_2酸化的方式将饮用水中pH值分别调至6.00、7.00和7.68三个水平,在不同的时间点取样,用离子色谱仪检测其溴化物含量。不同条件下,TAC吸附溴化物效率不同。实验结果表明,用稀盐酸浸泡作为活化方式,同时将饮用水的p H值调至6.00,在实验开始后的两个小时内TAC吸附溴化物效果最佳,能达到85.35%,此时溴化物含量为1.10μg/L,即使在后续的臭氧灭菌阶段,溴离子全部被氧化成溴酸盐,溴酸盐的值会在5μg/L以内,远小于GB 5749-2006和GB 8537-2018中溴酸盐的规定限值(10μg/L),同时,TAC对饮用水中的常量元素钾钠钙镁、微量元素锶及偏硅酸等影响不大(小于10%)。因此,在实际生产中,可先将饮用水中p H值调至6.00,然后采用盐酸溶液预处理后的TAC对饮用水中低量溴离子进行去除。     

流动注射化学发光法对饮用水中黄绿青霉素的在线检测

利用黄绿青霉素对鲁米诺-过氧化氢-纳米氧化铜化学发光体系的抑制作用检测饮用水中可能出现的突发性污染,并对测定体系的条件进行单因素试验和响应面试验优化。结果表明:在优化的实验条件下,黄绿青霉素检测线性范围为0.005~3 mg/L,检出限为8.2×10~(-5) mg/L。对质量浓度为0.005 mg/L的黄绿青霉素进行平行测定11次,相对标准偏差为2.3%,黄绿青霉素加标回收率范围为78%~91%。该方法简便快捷、实用性强,可应用于饮用水中黄绿青霉素突发性污染在线快速检测。     

络合混凝法去除香菇多糖中的镉污染

目的对香菇多糖提取过程中重金属的去除方法进行研究。方法在提取香菇多糖过程中使用络合以及混凝吸附的方法对香菇多糖粗提液进行处理,去除重金属镉(Cd),并对去除过程中p H值、试剂浓度以及KMn O4预氧化的作用进行了调查。结果香菇多糖提取过程中重金属镉的去除的工艺为:使用0.5 mg/L KMn O4预氧化30 min,在p H 10.0条件下使用络合剂25 mmol/L EDTA和25 mmol/L柠檬酸钠以及混凝剂50mg/L活性炭处理1 h;此工艺下香菇多糖中Cd的去除率高达96.3%。结论本研究为香菇以及其他食材、药材中重金属污染的处理问题提供了新的方法。     

国标两种测定饮用水中氯化物含量的方法

<正>氯化物是饮用水中常规理化指标,含量通常以CL-计,含有少量氯化物饮用水通常是无毒性的,研究表明,当饮用水中的氯化物含量超过250mg/L时,人对水的咸味开始有味觉感官,氯化物含量在250 mg/L~500mg/L之间时,对人体正常生理活动没有影响,大于500mg/L时,对胃液分泌、水代谢有影响;另外,近年来国外有专家研究发现,     

水中氟离子改性活性炭去除效果研究

采用不同浓度AlCl3对活性炭进行改性处理,通过改性活性炭对水中氟离子的去除效果,确定最佳AlCl3浓度;同时研究了活性炭类型、活性炭用量和吸附时间对水中氟离子去除效果的影响。结果表明,0.50 mol/L AlCl3改性后的活性炭吸附24 h可以使水中氟离子质量浓度由6.41 mg/L降至0.45 mg/L,氟离子去除率最大,因此0.50 mol/L为AlCl3改性最佳浓度。活性炭类型不同,改性后对水中氟离子去除效果不同。随着活性炭用量的增加和吸附时间的延长,水中氟离子去除率增大。氟离子质量浓度为14.14 mg/L的水,经0.8 g改性活性炭吸附9 h后,水中氟离子质量浓度小于1 mg/L。     

HPLC-MS/MS法检测桶装饮用水中壬基酚污染水平

建立高效液相-质谱法(HPLC-MS/MS)检测饮用水中壬基酚的方法,并对天津市桶装水企业从水源、生产、储存到消费全过程中壬基酚的污染水平进行调查。壬基酚的方法检出限为0.1μg/L,加标回收率为86.3%~92.2%,相对标准偏差为3.1%~4.6%。通过对饮用水检测,发现所采集样品企业的水源中壬基酚浓度范围在5.97μg/L~12.40μg/L,表明其水源已受到壬基酚的污染,而盛装容器无壬基酚明显迁移,桶装水的生产环节能有效去除部分壬基酚。     

脂肪酸对红曲菌M2液态发酵生产色素和桔霉素的影响

主要考察了红曲菌M2液态发酵过程中,5种脂肪酸对目的产物红曲色素及有害物质桔霉素的影响。结果表明,脂肪酸能促进菌体的生长,其中辛酸和癸酸的作用最明显。当辛酸和癸酸的浓度均为0.3m L/L时,菌体生物量分别比对照提高了20%和40%。另外,癸酸和软脂酸均能促进色素的合成。当癸酸和软脂酸的浓度分别为0.05m L/L和0.025g/L时,与对照相比,黄色素产量分别提高了42.9%和17.9%,红色素的产量分别提高了33.7%和22.6%。此外,0.1m L/L的辛酸能促进黄色素的合成但对红色素的合成无影响。对桔霉素而言,5种脂肪酸均能抑制或缓解桔霉素的合成。当辛酸、己酸和癸酸的浓度分别为0.4m L/L、0.4m L/L和0.3m L/L时,桔霉素的含量分别为对照的10.8%、26%和21%。实验最后通过调节初始p H值说明了脂肪酸对桔霉素的调节不是通过p H,而可能是参与了桔霉素的合成过程。     

离子色谱法测定饮用水中9种阴离子的含量

建立一种离子色谱检测方法,用于同时测定饮用水中9种阴离子。用离子色谱法,采用As19分离柱和AG19保护柱,柱温30℃,流速1.0 m L/min。9种阴离子都能达到基线分离,在0.005~10 mg/L的浓度范围内,各组分呈良好线性关系。平均回收率在91.5%~105.3%。本方法快速、简便、准确、灵敏,可满足生活饮用水和包装饮用水卫生标准检测要求。     

腐乳中桔霉素提取条件优化及检测方法研究

对腐乳中桔霉素提取条件进行优化,确定最佳提取条件为甲苯—乙酸乙酯—甲酸(7∶3∶1,V/V)超声处理10min,提取温度50℃,提取3次,提取液经浓缩后甲醇定容。建立高效液相色谱荧光检测器法测定腐乳中桔霉素,采用Hypersil ODS 2(250 mm×4.6 mm,5μm)为分析柱,水(p H2.5)—乙腈(70∶30,V/V)为流动相,流速0.8 m L/min,采用荧光检测器分析,外标法定量。结果表明:桔霉素在0.01~100.00μg/m L范围内线性良好(R2=0.999 99),检出限0.005 mg/kg,样品加标回收率为90.4%~107.9%,相对标准偏差(RSD6)小于6%,该方法操作简便、结果可靠。     

碳氮源对不同特性红曲菌株L、Idu产色素及桔霉素的影响

选取高产桔霉素红曲菌L及低产桔霉素红曲菌Idu,采用液态培养方式,研究不同种类碳氮源对这2种菌株产色素及桔霉素的影响。结果表明:对高产桔霉素菌株L而言,大米粉作为碳源其色素产量可达到72.02U/mL,桔霉素产量最低,为1.74mg/L,色素产量较高同时桔霉素产量得到很好控制,因此为菌株L的碳源最优选择;谷氨酸钠作为氮源其色素产量可达63.96 U/mL,桔霉素产量为8.13mg/L,色素产量最高同时桔霉素含量在可控范围之内,因此作为最优氮源的选择。对低产桔霉素菌株Idu而言,除蔗糖外,其余碳源对桔霉素产量均低于1mg/L,因此选择产色能力最高的麦芽糖作为碳源,色素产量可达56.94U/mL;桔霉素的产量随着菌种产色能力的增加而增加,因此选取产桔霉素最少的硫酸铵作为氮源以避免发酵产品桔霉素的超标。     

Efficacy of removal of CCL viruses under enhanced coagulation conditions

The focus of coagulation as a water treatment process is shifting to accommodate recent regulatory additions that strive to balance the risks between microbial and chemical contamination of drinking water. In this work, enhanced coagulation using increased ferric chloride dose and/or pH adjustment was evaluated for removal efficacy of viruses on the United States Environmental Protection Agency (USEPA) Contaminant Candidate List (CCL), their surrogates, and dissolved organic carbon (DOC). Jar tests demonstrated that optimal DOC removal was achieved using 40 mg/L FeCl3 at a pH between 5 and 6. Under these conditions, bench-scale testing resulted in a maximum removal of 2.58 log units of adenovirus type 4, 2.50 log units of feline calicivirus, 2.32 log units of MS2, 1.75 log units of PRD1, 1.52 log units of phi-X174, 2.49 log units of fr, and 56% of DOC. The trend in virus removals (MS2 and fr > PRD1 and phi-X174) was consistent between bench- and pilot-scale testing; however, pilot-plant removals exceeded bench-scale removals. Feline calicivirus was more efficiently removed than the bacteriophages, thereby suggesting potential for the bacteriophages as suitable surrogates, with MS2 and fr being more representative and PRD1 and phi-X174 (which were removed to a lesser extent) more conservative. The bacteriophages do not appear to be appropriate surrogates for adenovirus.     

N,N-dimethylsulfamide as precursor for N-nitrosodimethylamine (NDMA) formation upon ozonation and its fate during drinking water treatment

Application and microbial degradation of the fungicide tolylfluanide gives rise to a new decomposition product named N,N-dimethylsulfamide (DMS). In Germany, DMS was found in groundwaters and surface waters with typical concentrations in the range of 100-1000 ng/L and 50-90 ng/L, respectively. Laboratory-scale and field investigations concerning its fate during drinking water treatment showed that DMS cannot be removed via riverbank filtration, activated carbon filtration, flocculation, and oxidation or disinfection procedures based on hydrogen peroxide, potassium permanganate, chlorine dioxide, or UV irradiation. Even nanofiltration does not provide a sufficient removal efficiency. During ozonation about 30-50% of DMS are converted to the carcinogenic N-nitrosodimethylamine (NDMA). The NDMA being formed is biodegradable and can at least partially be removed by subsequent biologically active drinking water treatment steps including sand or activated carbon filtration. Disinfection with hypochlorous acid converts DMS to so far unknown degradation products but not to NDMA or 1,1-dimethylhydrazine (UDMH).     

流动注射化学发光法在线监测城市饮水中毒黄素突发性污染

基于碱性条件下毒黄素对鲁米诺-过氧化氢-纳米氧化铜化学发光体系光强的显著抑制作用,建立了一种在线监测和预警新方法。结合流动注射分析手段,通过微弱发光测量仪测定不同混合溶液光强。对4个影响因素进行单因素试验得出最佳结果,在此基础上经响应面优化各试验条件后进行标准曲线绘制及检出限测定,最后对不同水样进行加标回收。结果表明,该方法线性范围0.005~5.000mg/L,检出限0.001mg/L,加标回收率84%~114%。对浓度0.05 mg/L毒黄素平行测定11次,相对标准偏差(RSD)0.28%。该方法快捷便利,操作性强,可应用于城市饮水中毒黄素潜在突发性污染的快速在线监测和预警。     

Fate of endocrine-disruptor, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes

The potential occurrence of endocrine-disrupting compounds (EDCs) as well as pharmaceuticals and personal care products (PPCPs) in drinking water supplies raises concern over the removal of these compounds by common drinking water treatment processes. Three drinking water supplies were spiked with 10 to 250 ng/L of 62 different EDC/ PPCPs; one model water containing an NOM isolate was spiked with 49 different EDC/PPCPs. Compounds were detected by LC/MS/MS or GC/MS/MS. These test waters were subjected to bench-scale experimentation to simulate individual treatment processes in a water treatment plant (WTP). Aluminum sulfate and ferric chloride coagulants or chemical lime softening removed some polyaromatic hydrocarbons (PAHs) but removed <25% of most other EDC/ PPCPs. Addition of 5 mg/L of powder activated carbon (PAC) with a 4-h contact time removed 50% to >98% of GC/ MS/MS compounds (more volatile) and 10% to >95% of LC/ MS/MS compounds (more polar); higher PAC dosages improved EDC/PPCP removal. EDC/PPCP percentage removal was independent of the initial compound concentration. Octanol-water partition coefficients served as a reasonable indicator of compound removal under controlled PAC test conditions, except for EDC/PPCPs that were protonated or deprotonated at the test pH and some that contained heterocyclic or aromatic nitrogen. Separate chlorine or ozone experiments decreased the EDC/PPCP initial concentration by <10% to >90%; EDC/PPCPs were likely transformed to oxidation byproducts. Ozone oxidized steroids containing phenolic moieties (estradiol, ethynylestradiol, or estrone) more efficiently than those without aromatic or phenolic moieties (androstenedione, progesterone, and testosterone). EDC/PPCP reactivity with oxidants were separated into three general groups: (1) compounds easily oxidized (>80% reacted) by chlorine are always oxidized at least as efficiently by ozone; (2) 6 of the -60 compounds (TCEP, BHC, chlordane, dieldrin, heptachlor epoxide, musk ketone) were poorly oxidized (<20% reacted) by chlorine or ozone; (3) compounds (24 of 60) reacting preferentially (higher removals) with ozone rather than chlorine. Conventional treatment (coagulation plus chlorination) would have low removal of many EDC/PPCPs, while addition of PAC and/or ozone could substantially improve their removals. Existing strategies that predict relative removals of herbicides, pesticides, and other organic pollutants by activated carbon or oxidation can be directly applied for the removal of many EDC/PPCPs, but these strategies need to be modified to account for charged (protonated bases or deprotonated acids) and aliphatic species. Some compounds (e.g., DEET, ibuprofen, gemfibrozil) had low removals unless ozonation was used. Other compounds had low removals by all the WTP processes considered (atrazine, iopromide, meprobamate, TCEP), and removal processes capable of removing these types of compounds should be investigated.     

NOM removal by adsorption and membrane filtration using heated aluminum oxide particles

Heated aluminum oxide particles (HAOPs) are a newly synthesized adsorbent with attractive properties for use in hybrid adsorption/membrane filtration systems. This study compared removal of natural organic matter (NOM) from water by adsorption onto HAOPs with that by adsorption onto powdered activated carbon (PAC) or coagulation with alum or ferric chloride (FeCl3); explored the overlap between the NOM molecules that preferentially adsorb to HAOPs and those that are removed by the more conventional approaches; and evaluated NOM removal and fouling in hybrid adsorbent/membrane systems. For equivalent molar doses of the trivalent metals, HAOPs remove more NOM, and NOM with higher SUVA254, than alum or FeCl3. Most of the HAOPs-nonadsorbable fraction of the NOM can be adsorbed by PAC; in fact, that fraction appears to be preferentially adsorbed compared to the average NOM in untreated water. Predeposition of the adsorbents on a microfiltration membrane improves system performance. For the water tested, at a flux of 100 L/m2-hr, predeposition of 11 mg/L PAC and 5 mg/L HAOPs (as Al3+) allowed the system to operate 5 times as long before the transmembrane pressure increased by 1 psi and to remove 10-20 times as much NOM as when no adsorbents were added.     

Impact of treatment processes on the removal of perfluoroalkyl acids from the drinking water production chain

The behavior of polyfluoralkyl acids (PFAAs) from intake (raw source water) to finished drinking water was assessed by taking samples from influent and effluent of the several treatment steps used in a drinking water production chain. These consisted of intake, coagulation, rapid sand filtration, dune passage, aeration, rapid sand filtration, ozonation, pellet softening, granular activated carbon (GAC) filtration, slow sand filtration, and finished drinking water. In the intake water taken from the Lek canal (a tributary of the river Rhine), the most abundant PFAA were PFBA (perfluorobutanoic acid), PFBS (perfluorobutane sulfonate), PFOS (perfluorooctane sulfonate), and PFOA (perfluorooctanoic acid). During treatment, longer chain PFAA such as PFNA (perfluorononanoic acid) and PFOS were readily removed by the GAC treatment step and their GAC effluent concentrations were reduced to levels below the limits of quantitation (LOQ) (0.23 and 0.24 ng/L for PFOS and PFNA, respectively). However, more hydrophilic shorter chain PFAA (especially PFBA and PFBS) were not removed by GAC and their concentrations remained constant through treatment. A decreasing removal capacity of the GAC was observed with increasing carbon loading and with decreasing carbon chain length of the PFAAs. This study shows that none of the treatment steps, including softening processes, are effective for PFAA removal, except for GAC filtration. GAC can effectively remove certain PFAA from the drinking water cycle.The enrichment of branched PFOS and PFOA isomers relative to non branched isomers during GAC filtration was observed during treatment. The finished water contained 26 and 19 ng/L of PFBA and PFBS. Other PFAAs were present in concentrations below 4.2 ng/L The concentrations of PFAA observed in finished waters are no reason for concern for human health as margins to existing guidelines are sufficiently large.     

Removal of bromate from drinking water using the ion exchange membrane bioreactor concept

Bromate is a disinfection byproduct with carcinogenic properties that has to be removed from drinking water to concentrations below 10 or 25 microg/L. This work evaluates the applicability of the ion exchange membrane bioreactor (IEMB) concept for the removal of bromate from drinking water, in situations where nitrate is also present in concentrations up to 3 orders of magnitude higher than bromate. The batch results obtained show that the biological reduction of bromate was slow and only occurring after the complete reduction of nitrate. The specific bromate reduction rates varied from 0.027 +/- 0.01 mg BrO3(-)/g(cell dry weight) x h to 0.090 mg BrO3(-)/ g(cell dry weight) x h for the studied concentrations. On the other hand, transport studies, using anion exchange membranes showed that Donnan dialysis could efficiently remove bromate from polluted waters. Therefore, the use of a dense, nonporous membrane in the IEMB system, isolates the water stream from the biological compartment, allowing for the uncoupling of the water production rate from the biological reduction rate. The IEMB system was used for the treatment of a polluted water stream containing 200 microg/L of BrO3(-) and 60 mg/L of NO3(-). The concentrations of both ions in the treated water were reduced below the recommended levels. No bromate accumulation was observed in the biocompartment of the IEMB, suggesting its complete reduction in the biofilm formed on the membrane surface contacting the biocompartment. Therefore, the IEMB has proven to be a technology able to solve specific problems associated with the removal of bromate from water streams, since it efficiently removes bromate from drinking water even in the presence of nitrate, a known competitor of bromate biological reduction, without secondary contamination of the treated water by cells or excess of carbon source.     

Enrichment of deoxynivalenol and establishment of online early warning treatment system for drinking water

An online monitoring and early warning system was established to detect drinking water pollution from deoxynivalenol (DON). Flow injection chemiluminescence was selected as online monitoring tool for its low detection limit, fast detection process and broad linear range. The toxigenic strain of Fusarium graminearum (GDMCC3.507, freeze-dried powder) was incubated and grown on potato dextrose agar (PDA) culture medium under constant temperature of 26 °C for 5 days. Different culture conditions were investigated to determine the most suitable conditions to culture the fungi and enrich DON that produced by Fusarium graminearum. Powder activated carbon (PAC) was used to remove DON in drinking water. A dynamic threshold X ± 5SD was established to detect DON in drinking water effectively. Calculation of standard curve indicated that 6 mg DON could be easily extracted from 100 mg corn culture medium. Emergency detoxification was achieved by PAC and the removal rate reached 76% after 50 min of adsorption process. Once the chemiluminescence intensity exceeded the X ± 5SD value of the exact point during the monitoring process, the tap water was estimated to have excessive toxin. The establishment of this emergency system could provide a basis for dealing with sudden pollution of drinking water.     

苹果渣对Cr(Ⅵ)吸附性能的研究

采用静置吸附法,以苹果渣为生物吸附剂,研究其对Cr6+的吸附作用、吸附过程的影响因素、热力学和动力学行为。结果显示：苹果渣对Cr6+的吸附率随其粒径的减小而增大;Cr6+初始质量浓度相同时,吸附率随苹果渣加入量的增加而增大;苹果渣加入量相同时,吸附率总体上随Cr6+初始质量浓度增加呈增大趋势;正交试验得到3个因素对吸附效果的影响程度顺序为吸附温度＞pH值＞吸附时间,最优吸附条件为pH4、吸附温度60℃、吸附时间5h,此条件下吸附率为72.43%;苹果渣对Cr6+的吸附是先快速吸附,吸附时间超过120min后为慢速吸附,用Freundlich吸附等温式能较好地描述其吸附热力学情况,吸附动力学可以用二级动力学模型描述;对于50mg/L的Cr6+溶液,苹果渣为吸附剂时的最佳固液比为8:1000(m/V);苹果渣对中、低质量浓度Cr6+溶液(≤30mg/L)的吸附效果优于活性炭。     

红曲桔霉素高效液相色谱测定条件的优化

对高效液相色谱测定红曲桔霉素的方法进行优化 ,比较不同色谱柱及流动相组成对分离效果的影响 ,确定了采用色谱柱ZORBAXEclipseXDB C1 8( 5 μm ,2 5 0mm× 4 6mm) ,流动相组成为V(乙腈 )∶V(水 ) ( pH2 5 ) =35∶65。在优化条件下分离到的桔霉素色谱图经质谱鉴定为单一组分。在优化的色谱条件下绘制了标准曲线 ,低浓度标准样品的质量浓度与峰面积的线性关系良好 ,R2 =0 9997。标准桔霉素HPLC的最低检测质量浓度为 0 0 5mg/L