Catalytic Effect of Activated Carbon and Activated Carbon Fiber in Non-Equilibrium Plasma-Based Water Treatment

Catalysis and regeneration efficiency of granular activated carbon （GAC） and activated carbon fiber （ACF） were investigated in a non-equilibrium plasma water treatment reactor with a combination of pulsed streamer discharge and GAC or ACF. The experimental results show that the degradation efficiency of methyl orange （MO） by the combined treatment can increase 22% （for GAC） and 24% （for ACF） respectively compared to pulsed discharge treatment alone, indicating that the combined treatment has a synergetic effect. The MO degradation efficiency by the combined treatment with pulsed discharge and saturated GAC or ACF can increase 12% and 17% respectively compared to pulsed discharge treatment alone. Both GAC and ACF show catalysis and the catalysis of ACF is prominent. Meanwhile, the regeneration of GAC and ACF are realized in this process. When H202 is introduced into the system, the utilization efficiency of ozone and ultraviolet light is improved and the regeneration efficiency of GAC and ACF is also increased.

The Potential of Activated Carbon in the Treatment of Water for Human Consumption, a Study of the State of the Art and Its Techniques Used for Its Development

This review article addresses the use of biological activated carbon in water treatment and its techniques for its development, with the premise of analyzing the potential of Activated Carbon (AC) in the treatment of water for human consumption. For this end, it aims to identify the techniques used for the production of AC, use and its benefits, production from vegetable waste for water treatment. Activated carbon has the ability to selectively collect gases, liquids and impurities inside its pores, which is the reason it is widely used in filtration systems and for that the treatment of water, the coal fulfills the function of adsorbent, retaining in its pores certain types of impurities: large particles that cause undesirable color, taste or odor in the water. In the treatment of effluents, coal is used for clarification, deodorization and purification of effluents.

Fate and Behavior of Tetracycline Resistance Genes in Activated Carbon Adsorption

The accessibility of tetracycline resistance gene (tetG) into the pores of activated carbon (AC), as well as the impact of the pore size distribution (PSD) of AC on the uptake capacity of tetG, were investigated using eight types of AC (four coal-based and four wood-based). AC showed the capability to admit tetG and the average reduction of tetG for coal-based and wood-based ACs at the AC dose of 1 g·L-1 was 3.12 log and 3.65 log, respectively. The uptake kinetic analysis showed that the uptake of the gene followed the pseudo-second-order kinetics reaction, and the uptake rate constant for the coal-based and wood-based ACs was in the range of 5.97 × 10-12 - 4.64 × 10-9 and 7.02 × 10-11 - 1.59 × 10-8 copies·mg-1·min-1, respectively. The uptake capacity analysis by fitting the obtained experiment data with the Freundlich isotherm model indicated that the uptake constant (KF) values were 1.71 × 103 - 8.00 × 109 (copies·g-1)1-1/n for coal-based ACs and 7.00 × 108 - 3.00 × 1010 (copies·g-1)1-1/n for wood-based ones. In addition, the correlation analysis between KF values and pore volume as well as pore surface at different pore size regions of ACs showed that relatively higher positive correlation was found for pores of 50 - 100 Å, suggesting ACs with more pores in this size region can uptake more tetG. The findings of this study are valuable as reference for optimizing the adsorption process regarding antibiotic resistance-related concerns in drinking water treatment.

Improving AOC degradation rate by intensified biological process in advanced water treatment

The object of is to evaluate assimilable organic carbon（AOC） degradation rate by intensified biological technique in advanced water treatment. By artificially acclimating and cultivating strains attached onto carbon surface, the selected strains can be intensified for their degradation to organic matters. The research indicates that ozonation process increases AOC concentration considerably, however, it is beneficial to microdegradation. Temperature and empty bed contact time （ TEBC ） are two important factors affecting microbiology. From 14 to 27 ℃, intensified biological carbon can remove AOC better compared with granular activated carbon （GAC）. Under identical TERC, intensified technique increases more than 10% AOC reduction.

Pilot Study on Drinking Water Advanced Treatment by GAC-MF System

The pilot performance of the combined GAC-MF membrane process for drinking water advanced treatment was described. In the process of GAC adsorption, under the conditions of 20 min HRT and 6 m/h filtration rate, the removal efficiencies of UV_(254) and trichloromethane could reach 40% and 50% respectively and the UV_(254) and trichloromethane in system effluent was less than 0.015 cm^(-1) and 5μg/L respectively. In the post MF membrane process, MF membrane effectively retained the particles and bacteria in raw water. The effluent turbidity was less than 0.2 NTU and no bacteria were detected at all in permeate. A computer-controlled system was employed to control this system. The membrane operating parameters of backwash interval, duration and flux were studied. The backwash interval of 10-min, 20-min and 60-min was researched respectively, and the variation of trans-membrane pressure was also analyzed. Consequently short backwash interval was recommended under the same water consume.

Novel FGBAC reactor for controlling the leakage of microfauna in drinking water treatment

In order to reduce the microfauna leakage risk from a granular biological activated carbon （GBAC） reactor which employs granular activated carbon （GAC） as adsorption media in drinking water advanced treatment, a novel fiber and granular biological activated carbon （FGBAC） reactor which employs both GAC and activated carbon fiber （ACF） as adsorption media, was developed. The results showed that the species composition of microfauna leaking from FGBAC reactor is almost similar to that leaking from GBAC reactor, however the densities of microfauna leaking from FGBAC reactor is reduced by 26%-81% compared to those leaking from GBAC reactor. In addition, compared to GBAC reactor, FGBAC reactor can increase the removal efflciencies of chemical oxygen demand （COD） and turbidity by 7% and 10%, respectively, during the stable operation period of reactor.

Evaluation of alum-based water treatment residuals used to adsorb reactive phosphorus

Excess reactive phosphorus(PO4)in waterways can lead to eutrophication.A low-cost approach to reducing PO4 levels in surface water was evaluated using the alum-based water treatment residual(Al-WTR)or Al-WTR augmented with powdered activated carbon(PAC-WTR).Batch adsorption-desorption and continuous flow column experiments were performed to assess the specific adsorption capacities under various concentration and flow conditions.Both Al-WTR and PAC-WTR exhibited the ability to adsorb PO4.The overall,cumulative sorbed amount after a 28-d desorption step for Al-WTR was 33.93 mg/kg,significantly greater than the PAC-WTR value of 24.95 mg/kg(p<0.05).The continuous flow column experiments showed a theoretical PO4 uptake of 9.00 mg/g for Al-WTR and 7.14 mg/g for PAC-WTR over 720 h.When surface water was used,the Al-WTR and PAC-WTR columns removed 67.4%and 62.1%of the PO4,respectively.These results indicated that Al-WTR was more effective for in-field evaluation.

Affordable Water Filtration Technology for Disinfection By-Product Control for Small Rural Communities by Using Carbon Extracted from Local Fly Ash

The fly ash generated from local pulp and paper industries was transformed into activated carbon (AC) through physical activation process in a high temperature tube furnace in this study. Effects of two factors including activation temperature and activation time were investigated. Iodine number (IN), methylene blue value (MBV), and surface microstructure were all analyzed to assess the adsorption capacity of different carbon samples. The surface area of the carbon sample increased significantly from 486.44 m2/g to 847.26 m2/g before and after activation. The jar tests revealed that the use of 0.5 g (AC)/L (water) has the highest adsorption effectiveness. Meanwhile, the column filtration experiment indicated more than 60% of the organic matter can be removed by the carbon barrier within 2 hours filtration. The follow-up chlorination experiment illustrated that the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) could be considerably prevented after filtration. Above all, the cost-effective carbon filtration technology developed in this study can potentially be applied as a pre-treatment technology for intake source waters for local communities.

Drinking water production by uitrafiltration of Songhuajiang River with PAC adsorption

In recent years, membrane ultrafiltration （UF） of surface water for drinking water treatment has become a more attractive technology worldwide as a possible alternative treatment to conventional clarification. To evaluate the performance of ultrafiltration membranes for treatment of surface water in North China, a 48-m^2 low pressure hollow fiber membrane ultrafiltration pilot plant was constructed. Ultrafiltration was operated in cross-flow and with powdered activated carbon （PAC） adsorption. Turbidity was almost completely removed to less than 0.2 NTU （below Chinese standard 1 NTU）. It was found that PAC addition enhanced organic matter removal. The combined process of PAC/UF allowed to 41% removal of CODMn, 46% removal of DOC and 57% decrease in UV254 absorbance. The elimination of particles, from average 12000/ml in the raw water to approximately 15/ml in the permeated, was observed. When PAC concentration was below 30 mg/L, backwashing could recovery the membrane flux with backwash interval/backwashing duration of 1/30.

Sustainable Activated Carbons from Agricultural Residues Dedicated to Antibiotic Removal by Adsorption

The. objectives.of this study are to convert at laboratory s.cale agric.ultural residues into activated carbons （AC） with specific properties, to characterize them and to test them in adsorption reactor for tetracycline removal, a common antibiotic. Two new ACs were produced by direct activation with steam from beet pulp （BP-H2O） and peanut hu_lls （PH-H2O） in environmental friendly conditions BP-H2O and PH-H2Opresentcarbon content rangedcarbons with different intrinsic properties.

Activated Carbon and Clay Minerals for the Sorptive Removal of Denatonium Ions from Denatonium Benzoate Solutions

This study assessed the feasibility of utilizing activated carbon and clay minerals for treating water impacted with the bittering agent denatonium benzoate (DB). Our specific study objectives were to 1) evaluate denatonium ion sorption to smectite clay minerals (bentonite and hectorite) and activated carbon (powdered and granular) at constant pH and ionic strength and 2) examine the impact of pH on denatonium ion sorption to each solid material. The experimental results indicated that high doses (33,000 mg/L) of as-received granular activated carbon and as-received clay minerals completely removed denatonium from aqueous solutions containing 100 - 1000 mg/L denatonium benzoate. Powdered activated carbon at doses of 5 - 100 mg/L exhibited favorable monolayer sorption of denatonium ions from a pH 6.95, 70 mg/L aqueous denatonium benzoate solution with a Langmuir separation factor (r) of 0.481, a maximum sorption capacity (Sm) of 74 mg/g, and a Langmuir constant of 15.3 L/g. A maximum removal of 23% of denatonium was achieved at the highest powdered activated carbon dosage employed. Denatonium ion removal with peroxide treated bentonite and peroxide treated hectorite did not result in complete removal of the ion and exhibited favorable sorption as evidenced by Freundlich 1/n values ranging from 0.803 to 1.194;Freundlich constants (Kf) ranged from 8 ng/L to 575 ng/L. Denatonium ion sorption to peroxide treated bentonite appeared to depend on pH while hectorite sorption of denatonium ions was independent of hydrogen ion concentrations. For powdered activated carbon adsorption, as pH increased denatonium ion sorption decreased. Overall, the work demonstrates that denatonium can be effectively removed from water via activated carbon or clay mineral sorption.

Application of Green Technology Using Biological Means for the Adsorption of Micro-Pollutants in Water

It is true that the world we have today is not the world we use to know. The Covid-19 pandemic has paralyzed all sector, hence the need for safety and enabling environment for mankind is of high importance. Adsorption technology is far the best and cheapest treatment technology for water and has extensively proven its worth for the uptake of micro-pollutant from surface, ground and water which are the major channels of home water. Over the years activated carbon is considered as the most common and universally used adsorbent for the eradication of different types of micro-pollutants from water. The contamination of surface water by micro-pollutant is a potential threat for the production of high quality and safe drinking water. Adsorption operation onto granulated activated carbon (GAC) in fixed-bed filters is often applied as a remedying step in the synthesis of safe and drinkable water. Activated carbon actively tends to act as a carrier material for a thin usually resistant layer of microorganisms (mostly bacteria) that forms on the coat of various surfaces (biofilm), hence biological simplification can be an alternative removal approach that can be adopted in granulated activated carbon filters. To evaluate the capacity of biofilm to biologically simplify micro-pollutants, it is very imperative to distinguish adsorption from biological simplification (biodegradation) as a removal mechanism. Experiment was carried out under the operating condition of a temperature range of 6?C to 20?C with biologically activated and autoclaved GAC to assess the biological simplification by the biofilm adsorbed on the GAC surface. Five micro-pollutants were selected as model compounds, of which some of them were biologically simplified by the GAC biofilm. Additionally, we observed that temperature can increase or decrease adsorption. Conclusively, comparison was made on the adsorption capacity of granulated activated carbon used for more than 50,000 beds.

Experimental Design Technique on Removal of Hydrogen Sulfide using CaO-eggshells Dispersed onto Palm Kernel Shell Activated Carbon：Experiment,Optimization,Equilibrium and Kinetic Studies

This study presents the use of chicken eggshells waste utilizing palm kernel shell based activated carbon（PKSAC） through the modification of their surface to enhance the adsorption capacity of H2S. Response surface methodology technique was used to optimize the process conditions and they were found to be： 500 mg/L for H2S initial concentration, 540 min for contact time and 1 g for adsorbent mass. The impacts of three arrangement factors（calcination temperature of impregnated activated carbon（IAC）, the calcium solution concentration and contact time of calcination） on the H2S removal efficiency and impregnated AC yield were investigated. Both responses IAC yield（IACY, %） and removal efficiency（RE, %） were maximized to optimize the IAC preparation conditions. The optimum preparation conditions for IACY and RE were found as follows： calcination temperature of IAC of 880 ℃, calcium solution concentration of 49.3% and calcination contact time of 57.6 min, which resulted in 35.8% of IACY and 98.2% RE. In addition, the equilibrium and kinetics of the process were investigated. The adsorbent was characterized using TGA, XRD, FTIR, SEM/EDX, and BET. The maximum monolayer adsorption capacity was found to be 543.47 mg/g. The results recommended that the composite of PKSAC and Ca O could be a useful material for H2S containing wastewater treatment.

过碳酸盐高级氧化技术在水处理中的研究进展

近年来,活化过碳酸盐高级氧化技术具有低成本、安全、稳定等特点,已广泛用于处理水中的各类有机污染物,有望成为一种新兴的环境友好型水处理技术。该文介绍了活化过碳酸盐降解有机污染物的机理;系统综述了均相活化、非均相活化、物理活化、其他活化过碳酸盐的活化方法与活化反应机理;总结了过碳酸盐高级氧化法在水处理中的应用,重点阐述了过碳酸盐高级氧化法在去除水中的有机污染物、膜污染控制、污泥脱水、污泥厌氧消化等方面的应用研究现状;最后,指出目前水处理研究领域活化过碳酸盐高级氧化技术存在的问题,并对未来的重点研究方向进行了展望。

Synthesis and Application of Granular Activated Carbon from Biomass Waste Materials for Water Treatment:A Review

There is an increased global demand for activated carbon(AC)in application of water treatment and purification.Water pollutants that have exhibited a greater removal efficiency by AC included but not limited to heavy metals,pharmaceuticals,pesticides,natural organic matter,disinfection by-products,and microplastics.Granular activated carbon(GAC)is mostly used in aqueous so-lutions and adsorption columns for water treatment.Commercial AC is not only costly,but also obtained from non-renewable sources.This has prompted the search for alternative renewable materials for AC production.Biomass wastes present a great potential of such materials because of their availability and carbonaceous nature.This in turn can reduce on the adverse environmental effects caused by poor disposal of these wastes.The challenges associated with biomass waste based GAC are their low strength and attrition resistance which make them easily disintegrate under aqueous phase.This paper provides a comprehensive review on recent advances in production of biomass waste based GAC for water treatment and highlights future research directions.Production parameters such as granulation conditions,use of binders,carbonization,activation methods,and their effect on textural properties are discussed.Factors influencing the adsorption capacities of the derived GACs,adsorption models,adsorption mechanisms,and their regeneration potentials are reviewed.The literature reveals that biomass waste materials can produce GAC for use in water treatment with possibilities of being regenerated.Nonetheless,there is a need to explore 1)the effect of preparation pathways on the adsorptive properties of biomass derived GAC,2)sustainable production of biomass derived GAC based on life cycle assessment and techno-economic analysis,and 3)adsorption mechanisms of GAC for removal of contaminants of emerging concerns such as microplastics and unregulated disinfection by-products.

天津某净水厂引江水强化处理技术研究

天津某净水厂主水源为南水北调中线工程引江水,该水厂在常规工艺基础上增设预臭氧、后臭氧和活性炭强化工艺,以期进一步提升出水水质。建立小试试验装置,对以上各工艺强化常规工艺处理引江水的效果展开探讨。结果表明,絮凝剂PAC和FeCl_(3)的最佳投加量均为17 mg/L;在常规工艺基础上增设预臭氧或后臭氧工艺可以有效提升有机物的去除效果,增设活性炭工艺可同时提升浊度和有机物的去除效果,同时增设后臭氧和活性炭工艺强化去除浊度和有机物的作用最显著。预臭氧和后臭氧的最佳投加量均为1.0 mg/L,当原水中溴离子质量浓度高达150μg/L时,常规-后臭氧工艺、预臭氧-常规-后臭氧工艺中臭氧的投加量应调整为≤0.5 mg/L。

真空紫外在水处理中的作用机理及其研究进展

介绍了真空紫外线(VUV,254+185 nm)高级氧化技术辐射水产生活性氧化物质降解水中污染物的作用机理以及在水处理行业中的应用,同时包括VUV辐射氧气或者空气产生臭氧。概述了VUV工艺的优点和局限性以及影响脱色的主要因素,并对其在水处理中的可能应用及未来发展方向进行展望,为真空紫外在有机染料废水后续研究提供参考,提出研究建议。

供排水系统中全氟和多氟烷基化合物(PFAS)的检测与去除研究进展

随着工业的发展,全氟和多氟烷基化合物(PFAS)在日常生活和生产中的应用日益广泛,对水环境的影响呈加剧趋势。由于PFAS良好的水溶性,其可以随着水循环在环境中迁移转化,最终对人体健康产生不利影响。因此,中国和欧美国家已着手制定相关标准和法律法规,以限制PFAS的使用。在系统性总结水环境中PFAS的来源、浓度和转化过程的基础上,文章对比了色谱法、总可氧化前体(TOP)法和传感器等检测方法以及传统物化生方法、高级氧化技术以及焚烧工艺等去除技术,旨在为PFAS的监测与控制提供理论支持。结果表明,饮用水中PFAS质量浓度普遍超过0.1 ng/L,且PFAS在供排水处理过程中的去除存在两大局限:一是检测技术仅能覆盖少数PFAS类型;二是目前的去除方法无法彻底消除PFAS风险,或导致去除率差,或转化为短链氟化物,引发更多潜在环境风险。

臭氧活性炭工艺处理多种新污染物复合污染研究

以南方某流域水体可检出的SD、SMZ、HCB、马拉硫磷和BPA等新污染物为研究对象,进行复合新污染物共存的原水加标处理试验,研究预处理-常规处理-臭氧活性炭工艺处理效果。结果表明,SD、SMZ、BPA与COD_(Mn)均具有较好的相关性;生物预处理工艺对SD、SMZ、HCB、马拉硫磷和BPA去除率分别为23.97%、21.20%、6.08%、16.26%和23.76%,生物预处理最优停留时间是120min,最优气水比是1:2;常规处理工艺对SD、SMZ、HCB、马拉硫磷和BPA的去除率分别为18.02%、20.08%、23.02%、8.26%和16.53%,常规处理中SMZ和马拉硫磷的混凝剂最佳投加量为15mg/L,其余3种新污染物的混凝剂最佳投加量为20mg/L;深度处理工艺对SD、SMZ、HCB、马拉硫磷和BPA的去除率分别为49.13%、53.80%、60.20%、77.07%和71.50%,深度处理最佳臭氧投加量是3mg/L,最佳臭氧接触时间为24min,最优炭床停留时间是25min。试验工艺对复合新污染物具有良好的去除作用,对SD、SMZ、HCB、马拉硫磷和BPA的总去除率达到了69.86%、73.10%、73.65%、83.74%和82.72%,试验条件下出水的HCB、马拉硫磷和BPA满足《生活饮用水卫生标准》(GB5749-2022),出水的磺胺嘧啶和磺胺二甲嘧啶满足欧美发达国家的水质标准。

臭氧活性炭深度处理工艺中微生物泄漏防控的生产性试验研究

本研究以上海市某水厂臭氧活性炭深度处理工艺为研究对象,研究活性炭滤池微生物泄漏特征,并通过生产性试验优化臭氧和活性炭工艺防控微生物泄漏。优化前活性炭滤池出水中细菌、总大肠菌群和异养菌均有不同程度的泄漏,对应总数分别比进水时增加了8倍、7倍和21倍;将臭氧投加量控制在0.8 mg·L^(-1)以上,炭滤池反冲洗周期缩短至3 d,同时气冲和水冲时间减少至5 min+5 min,对于控制活性炭滤池微生物泄漏有较好的效果。