Adsorption of acid and basic dyes by sludge-based activated carbon:Isotherm and kinetic studies

A batch experiment was conducted to investigate the adsorption of an acid dye(Acid Orange 51) and a basic dye(Safranine) from aqueous solutions by the sludge-based activated carbon(SBAC). The results show that the adsorption of Acid Orange 51 decreases at high p H values, whereas the uptake of Safranine is higher in neutral and alkaline solutions than that in acidic conditions. The adsorption time needed for Safranine to reach equilibrium is shorter than that for Acid Orange 51. The uptakes of the dyes both increase with temperature increasing, indicating that the adsorption process of the dyes onto SBAC is endothermic. The equilibrium data of the dyes are both best represented by the Redlich-Peterson model. At 25 °C, the maximum adsorption capacities of SBAC for Acid Orange 51 and Safranine are 248.70 mg/g and 525.84 mg/g, respectively. The Elovich model is found to best describe the adsorption process of both dyes, indicating that the rate-limiting step involves the chemisorption. It can be concluded that SBAC is a promising material for the removal of Acid Orange 51 and Safranine from aqueous solutions.

Removal of lead(II) from aqueous solutions by activated carbon developed from surplus sludge

Activated carbon(AC) was prepared from surplus sludge using chemical activation method with the assistance of ZnCl2. The influences of process parameters on the AC's specific surface area and adsorption capacity for Pb2+ were examined to optimize these parameters. The optimal conditions for the preparation of AC were determined to be activation temperature of 500 °C, activation time of 1 h, impregnation ratio of 1:1(solid-to-liquid volume) with the 30% ZnCl2 solution(mass fraction), giving the BET surface area of 393.85 m2/g and yield of 30.14% with 33.45% ash. Also, the pyrolysis temperature was found to be the most important parameter in chemical activation. FTIR spectra provided the evidence of some surface structures such as C=C and C—O—C. In the adsorption studies, a rise in solution pH led to a significant increase in adsorption capacity when the pH value varied from 3.0 to 7.0, and the optimal pH for removal of Pb2+ was 7.0. It was observed that the pseudo-second-order equation provided better correlation for the adsorption rate than the pseudo-first-order and the Langmuir model fitted better than the Freundlich model for adsorption isotherm. The adsorption capacity of AC to Pb2+ was 11.75 mg/L at solution pH 7.0, the equilibrium time 480 min and 25 °C. Moreover, the adsorption process is endothermic according to the value of enthalpy change.

Systematic physicochemical characterization,carbon balance and cost of production analyses of activated carbons derived from(Co)-HTC of coal discards and sewage sludge for hydrogen storage applications

Hydrothermal carbonization(HTC)technologies for producing value-added carbonaceous material(hydrochar)from coal waste and sewage sludge(SS)waste might be a long-term recycling strategy for hydrogen storage applications,cutting disposal costs and solving waste disposal difficulties.In this study,hydrochars(HC)with high carbon content were produced using a combination of optimal HTC(HTC and Co-HTC)and chemical activation of coal tailings(CT),coal slurry(CS),and a mixture of coal discard and sewage sludge(CB).At 850℃and 800℃,respectively,with a KOH/HC ratio of 4:1 and a residence time of 135 min,activated carbons(ACs)with the highest Brunauer–Emmett–Teller specific surface(S_(BET))of 2299.25 m^(2)g^(−1)and 2243.57 m^(2)g^(−1)were obtained.The hydrogen adsorption capability of the produced ACs was further studied using gas adsorption isotherms at 77 K.At 35 bars,the values of hydrogen adsorbed onto AC-HCT(AC obtained from HTC of CT),AC-HCS(AC obtained from HTC of CS),and AC-HCB(AC obtained from HTC of the blending of coal discard(CD)and SS)were approximately 6.12%,6.8%,and 6.57%in weight,respectively.Furthermore,the cost of producing synthetic ACs for hydrogen storage is equivalent to the cost of commercial carbons.Furthermore,the high proportion of carbon retained(>70%)in ACs synthesized by HTC from CD and SS precursors should restrict their potential carbon emissions.

MALODOR POLLUTION FROM REFINERY SEWAGE TREATMENT SYSTEM AND TREATMENT TECHNOLOGY

Main malodor pollutants from oil separator of Refinery A are hydrocarbons and a small quantity of sulfides. Main malodor pollutants from surface aeration tank of Refinery B are sulfides, especially CH 3SH. And main malodor pollutants from bubbling aeration tank of Refinery C are also sulfides, of which H 2S concentration is the highest. Catalytic combustion technology is applied to treat malodorous gas from oil separator of Refinery A, in which the total hydrocarbon removal was over 97%. The purified gas meets the national standard. Activated carbon adsorption is used to treat malodorous gas from surface aeration tank of Refinery B, and main pollutant CH 3SH removal reached up to 98%～100%. As for malodorous gas from bubbling aeration tank of Refinery C, bio packing tower is used and the removals of hydrogen sulfide, organic sulfides and benzene series reached up to 80%～98%.

油田污水过滤罐活性炭原位氧化再生

采用过硫酸铵(APS)热活化复合超声波及甲醇萃取的方法原位再生油田污水过滤罐活性炭,考察了初始pH值、过硫酸铵用量、反应温度、反应时间、超声波强化APS功率及甲醇浓度对活性炭再生效果的影响。结果表明,APS热活化复合超声波及甲醇萃取的方法再生效果更好。当初始pH值为7,APS溶液浓度为500 g/L,反应温度为70℃,反应时间为30 min,超声强度为60%,甲醇萃取浓度100%,再生2次,活性炭的再生效率分别为79.16%和66.84%。

Effects of chemical modification on physicochemical properties and adsorption behavior of sludge-based activated carbon

This study aimed to explore the adsorption performance of sludge-based activated carbon(SBC)towards dissolved organic matters(DOMs)removal from sewage,and investigated the modification effect of different types of chemicals on the structure of synthesized SBC.Waste activated sludge(WAS)was used as a carbon source,and HCl,HNO 3,and Na OH were used as different types of chemicals to modify the SBC.With the aid of chemical activation,the modified SBC showed higher adsorption performances on DOMs removal with maximum adsorption of 29.05 mg/g and second-order constant(k)of 0.1367(L/mol/sec)due to the surface elution of ash and minerals by chemicals.The surface elemental composition of MSBC suggested that the content of C-C and C-O functional groups on the surface of modified sludge-based activated carbon(MSBC)played an important role on the adsorption capacities of MSBC towards DOMs removal in sewage.Additionally,the residual molecular weight of DOMs in sewage was investigated using a 3-dimension fluorescence excitationemission matrix(3 D-EEM)and high-performance size exclusion chromatography(HP-SEC).Results showed that the chemical modification significantly improved the adsorption capacity of MSBC on humic acids(HA)and aromatic proteins(APN),and both of Na OH-MSBC and HCl-MSBC were effective for a wide range of different AMW DOMs removal from sewage,while the HNO 3-MSBC exhibited poorly on AMW organics of 2,617 Da and 409 Da due to the reducing content of macropore.In brief,this study provides reference values for the impact of the chemicals of the activation stage before the SBCs application.

中心脉冲气-液-固循环流化床微生物燃料电池产电特性

为进一步提升微生物燃料电池(MFC)的电化学性能,设计并搭建了一个中心脉冲气-液-固循环流化床微生物燃料电池(CPCFB-MFC),通过设计多组实验工况研究了脉冲液流频率和幅值、颗粒循环速率及气体流量对CPCFB-MFC产电及污水处理特性的影响。在中心液流脉冲频率为0.25 Hz、脉冲幅值为0.08 m/s、颗粒循环速率为3.3 kg/(m^(2)·s)、气体流量为2 L/min条件下,CPCFB-MFC的输出电压达到最高(为649.2 mV),此时污水处理时间最短(为77 h)。通过对比不同工况的污水处理效率和综合能耗,证明了在反应器内采用脉冲液流和气-液-固循环运行方式能进一步提升MFC的综合性能。这项工作对推动微生物燃料电池技术的产业化具有重要意义。

污水生化处理工艺发展阶段化技术特征及未来趋势

百余年来,伴随人类社会和科技日新月异,污水生化处理技术也在实现快速发展与不断迭代,新工艺与新反应器、新功能微生物与新生化代谢途径不断被提出、发现和解析,并进一步推动了污水处理技术的进步与升级。回顾了过去百余年污水生化处理技术发展历程,就典型污水生化工艺,结合技术研发进展、技术成熟度及案例应用情况,给出了不同生化处理工艺代际划分与技术发展期“S曲线”,分析了近些年来新涌现出的一些革新性污水生化处理工艺的技术原理、技术特征,结合实际案例分析了工艺技术特征、技术优势与总体效能,从工艺强化、绿色低碳与集约高效等方面总结了未来污水处理发展的技术趋势,以期为“双碳背景”下排水系统提质增效工作、未来国内前瞻性污水厂工艺设计与运行提供参考和借鉴。

城市排水系统中挥发性有机污染物检测及处理措施研究

针对目标城市污水排水系统中挥发性有机污染物含量超标的问题,以排水系统出水端水样为研究对象,对水样中的典型挥发性有机污染物含量进行了检测,并在原有混凝处理工艺的基础上进行改进,形成了混凝+活性炭吸附处理工艺,优化了相关处理参数。结果表明:经原有混凝工艺处理后,污水中三种挥发性有机污染物的含量均较高,无法达到GB 18918—2002中规定的排放要求。D型活性炭对污水的处理效果最好;活性炭的投加量越大,吸附时间越长,污水中挥发性有机污染物的含量越小,去除率越大;随着污水p H值的升高,污水中挥发性有机污染物的含量先减小后增大,去除率则先增大后减小。确定最佳处理参数为选择活性炭类型为D型、投加质量浓度为150 mg/L,吸附时间为6 h,污水p H值为5,此时污水中三种挥发性有机污染物的含量均能达到GB 18918—2002中规定的排放要求。

提标升级对乡镇污水处理厂碳排放特征的影响

在碳达峰、碳中和和流域水污染防治的背景下,乡镇污水处理厂减污降碳协同势在必行。基于成都市某乡镇市政污水处理厂2016—2022年水质水量数据,分析提标升级前后化学需氧量、氨氮、总磷、总氮的时间变异性,利用《IPCC 2006国家温室气体清单指南》(2019年修订版)、《城镇水务系统碳核算与减排路径技术指南》评估直接、间接碳排放强度特征,探究提标升级前后碳排放量对季节、水质及污染物削减量的响应。结果表明:1)污水处理厂主体工艺从周期循环活性污泥法(CASS)升级为厌氧-缺氧-好氧-膜生物反应器法(AAO-MBR)后,出水水质满足DB 51/2311—2016《四川省岷江、沱江流域水污染物排放标准》,升级后通过增加碳源、利用MBR膜截留污泥等措施,使出水水质指标更加稳定,对污染物的处理效率更高;2)提标升级后,直接、间接碳排放强度分别为0.296和1.082 kg/m^(3)(以CO_(2)当量计),分别增加41.59%和105.70%,且夏季碳排放强度显著低于其他季节(P<0.01),升级前后的间接碳排放强度均高于直接碳排放强度;3)提标升级后,总碳排放强度增加了0.643 kg/m^(3)(以CO_(2)当量计),工艺升级导致的电耗增加,使得间接碳排放强度变化更显著。乡镇污水处理厂提标升级在提高处理效能的同时也增加了碳排放量,建议在工艺改造中协同考虑污染物去除与能耗控制,以实现减污降碳协同增效。

生物接触氧化耦合生物活性炭工艺处理高盐污水实验总结

针对炼化企业废水盐含量高、稳定达标处理难、能耗高等问题,提出了生物接触氧化-生物活性炭工艺。通过梯度提高进水盐含量的方法成功驯化出耐盐菌,启动了生物接触氧化单元,池中生物挂膜良好,脱氮除碳效果显著,出水COD(化学需氧量)可稳定控制在90 mg/L以下,总氮在15 mg/L以下。菌群分析结果表明,在高盐含量(高盐)废水环境中,接触氧化单元生物膜中菌群数量和多样性较接种污泥发生明显改变,主要功能菌为Thiovirga、Thauera、Flavobacterium、Gemmobacter、Hydrogenophaga等。在生物活性炭单元,通过耐盐高效菌剂与活性炭的有机结合,提高了该单元对进水COD波动的抗冲击能力,活性炭表面形成生物膜,系统运行稳定,可控制出水COD基本在60 mg/L以下,氨氮质量浓度在2 mg/L以下,总氮在15 mg/L以下。全流程以生物降解为核心,工艺流程短、运行成本低,为高盐污水的稳定达标处理提供了技术支撑。

生活污水尾水回用对稻田土壤微生物量碳氮和土壤酶活性的影响

为探讨农村生活污水尾水回用对稻田土壤微生物量碳氮和酶活性的影响,通过田间试验,以池塘水灌溉下不施肥和常规施肥为对照,探讨尾水耦合氮肥施加方式对稻田土壤微生物量碳氮、土壤酶(脲酶、磷酸酶、硝酸还原酶、过氧化氢酶、蔗糖酶)活性以及土壤养分等的影响。结果表明,2019年和2021年收获期尾水仅施蘖肥、尾水常规施肥、尾水减氮施肥土壤微生物量碳较常规施肥处理分别增加了28.75%~34.75%和14.43%~23.63%,土壤微生物量氮分别增加了7.10%~16.04%和15.9%~46.88%。尾水灌溉处理脲酶活性两年间分别增加了34.92%~51.61%和0.98%~2.94%,有机质分别增加了1.11%~11.10%和6.38%~11.40%,年际间比较发现无论池塘水灌溉还是尾水灌溉土壤有机质含量均有上升趋势,而尾水灌溉处理土壤有机质增幅更大。综上所述,尾水灌溉提高了稻田土壤有机质、微生物量碳氮的含量和脲酶活性,说明尾水回用在一定程度上会增加土壤肥力,具有一定的土壤改良作用,但长期回用下的环境安全性还需要通过进一步试验确定。

城市污水处理系统中重金属污染物的检测及治理技术研究

为了明确城市污水处理系统中重金属元素的变化情况,提出更加高效的重金属污染物治理措施,以某城市污水处理厂A/O处理工艺中不同处理单元的水样为研究对象,采用电感耦合等离子体发射光谱仪和原子荧光光度计对水样中不同类型的重金属元素(Cu、Pb、Cr、Cd、Ni和Hg)质量浓度进行了检测,并针对性地开展了活性炭吸附试验。结果表明:目标城市污水处理厂进水水样中重金属Cu、Pb、Cr、Cd和Hg的质量浓度均超标,而经过A/O工艺处理后,不同处理单元出口的水样中重金属元素的质量浓度均有所降低,但最终出口水样中Pb和Cr的质量浓度仍超标,而Cu元素的质量浓度也高达0.283 mg·L^(-1)。活性炭吸附试验的最佳工艺参数为:吸附剂类型为改性活性炭E,吸附剂投加量为200mg·L^(-1),吸附时间为10min。在此最佳工艺条件下,水样中重金属Cu、Pb和Cr的质量浓度可分别降低至0.005 2、0.001 9、0.001 3 mg·L^(-1),均能达到国家标准GB/T 18918—2002中的排放要求。

江苏某化工园污水处理厂提标改造设计

为了响应苏政办提出的提标改造要求,对江苏某化工园污水处理厂进行提标改造设计。改造思路为新增臭氧预处理单元处理农药类企业排水,科学合理地结合一期、二期现有建构筑物,改造/利旧预处理单元、生化处理单元和深度处理单元,增设活性碳吸附深度处理单元,确保出水各指标达标排放。经过了一年多的运行,污水处理厂进水水质满足设计进水水质要求,出水水质连续稳定达到《城镇污水处理厂污染物排放标准》(GB18918-2002)表1一级A排放标准,持续改善园区河道及相关海域的水环境,减轻了企业污水处理负担,增强了园区招商引资的吸引力,提高了附近居民的生活质量,也为类似化工园污水处理厂的改造提供一定参考。

Effect of biomass addition on the surface and adsorption characterization of carbon-based adsorbents from sewage sludge

Sewage sludge with the additive corn cob was used as prescusor to prepare sludge-based carbon adsorbents by pyrolysis method. And then, the carbonizated products were activated with potassium hydroxide. The mixing ratio of the corn cob to sewage sludge was investigated. The surface area and pore size distribution, elemental composition, surface chemistry structure and the surface physical morphology were determined and compared. The results demonstrated that the addition of corn cob into the sewage sludge sample could effectively improve the surface area （from 287 to 591 m 2 /g） and the microporosity （from 5% to 48%） of the carbon based adsorbent, thus enhancing the adsorption behavior. The sulfur dioxide adsorption capacity was measured according to breakthrough test. It was found that the sulfur dioxide adsorption capacity of the adsorbents was obviously enhanced after the addition of the corn cob. It is presumed that not only highly porous adsorbents, but also a high metallic content of these materials are required to achieve good performances.

无动力废气处理设备对VOCs的处理效果及应用

根据公司污水井无组织排放废气特征,在实验室培养制取生物菌,将其固定在活性炭上,装填于原位无动力废气处理装置中,在实验室和含油污水井上验证装置对无组织排放气体的去除效果,成功解决了污水井无组织排放气体难以治理的问题。

低碳源生活污水生物脱氮工艺研究进展

针对低碳源生活污水总氮脱除的难题,分别从传统生物脱氮工艺、新型生物脱氮工艺、碳源对污水脱氮的影响进行了综述。传统生物脱氮工艺主要包括活性污泥法、生物膜法、泥膜复合法,相较于单一的传统活性污泥法或生物膜法,泥膜复合工艺对低碳源生活污水可以获得较高的脱氮效果;新型生物脱氮工艺主要包括短程硝化反硝化、厌氧氨氧化、同步硝化反硝化及自养反硝化,其中短程硝化反硝化需严格控制运行条件以获得较高的总氮去除率;厌氧氨氧化无须外碳源,但需要严格控制环境条件以保持厌氧氨氧化菌的活性;同步硝化反硝化工艺运行参数的波动对处理效果影响显著;自养反硝化节省了外碳源的投入,但保持自养反硝化微生物的活性是关键;碳源作为污水生物脱氮反硝化过程的重要影响因素,主要有外投加单一碳源、外投加组合碳源及利用内源碳,需要根据具体处理的污水水质水量情况,以及可利用的碳源情况进行选择。为此,对低碳源生活污水脱氮技术提出了展望,可从微观角度重点研究新型生物脱氮工艺的机制机理;通过工艺的组合优化,合理选择外碳源,充分利用污水中内碳源;新型生活污水脱氮工艺进行组合,对各运行参数进行优化,以期获得高效化、低碳化的脱氮技术。

焦化废水异味治理工艺及其效果评估

为解决煤化工公司在生产中焦化废水所产生异味对周围环境造成污染的问题,在对本公司污水处理工艺现状综合分析的基础上,提出对调节池、除油池、缺氧池以及厌氧池进行加盖处理,采用化学洗涤+低温等离子体技术+活性炭吸附工艺对废气进行治理的思路,在确定洗涤液和操作工艺参数后,对该异味治理工艺的效果进行综合评估,得到理想结论。

污泥基活性炭吸附空气中甲醛的研究

以城市污水处理厂脱水污泥为原料,氯化锌为活化剂制备污泥基活性炭,采用BET比表面积测试、扫描电镜(SEM)、傅里叶红外光谱(FTIR)等方法研究其理化性能,利用动态吸附实验系统和蒸馏装置,将污泥基活性炭与选定的商业活性炭进行了甲醛吸附性能对比,并利用热重分析法研究了甲醛在各活性炭上的脱附情况.结果表明,污泥基活性炭对空气中浓度分别为498,0.41mg/m3的甲醛均有很好的吸附效果,吸附量分别可达74.27,7.62mg/g,最大去除率分别为83.72%和89.56%,其吸附性能与选定的商业活性炭相当,特别是在处理浓度为0.41mg/m3甲醛时超过选定的商业活性炭.该污泥基活性炭BET比表面积为509.88m2/g,氮吸附等温线属于BDDT分类中的I-B型,表明其具有大量的超微孔和极微孔,更适用于低浓度甲醛的吸附.FTIR分析表明其表面含有各种含氮基团,特别是-NH2的存在,可能形成化学吸附中心,但从吸附甲醛后各活性炭的微商热重分析(DTG)曲线可以看出,各甲醛在活性炭上的吸附主要为物理吸附.

污泥制备活性炭对Pb(II)和Ni(II)的吸附和回收利用

在静态条件下研究了用污泥制备的活性炭吸附剂去除水溶液中Pb(Ⅱ)、Ni(Ⅱ)的效果,考察了溶液pH值、吸附时间、吸附剂用量和Pb(Ⅱ)、Ni(Ⅱ)的初始浓度对去除率的影响。结果表明,污泥制备的活性炭吸附剂对Pb(Ⅱ)、Ni(Ⅱ)具有较强的吸附性能,pH值是影响吸附的主要因素;吸附过程符合Langmuir吸附等温式;在试验条件下,其对Pb(Ⅱ)具有更高的去除能力。还探讨了吸附Pb(Ⅱ)、Ni(Ⅱ)后回收铅和镍的可行性。