Granular Activated Carbon Dosage Research Articles

Advanced electro-oxidation-adsorption process for chlorate removal from synthetic and municipal wastewater treatment effluents

This study evaluates a hybrid electro-oxidation-adsorption process for chlorate removal in wastewater treatment. Using a specialized reactor, we investigated the influence of operational parameters including current density, reaction time, granular activated carbon (GAC) dosage, electrode spacing, and pH. Optimal removal efficiency of 82.40 % was achieved under the following conditions: 75 A/m² current density, 5 min reaction time, 20 g/L GAC dosage, 2 cm electrode spacing, and a pH of 2. This method outperforms traditional adsorption and electrochemical oxidation, offering a promising solution for reducing chlorate-related environmental impacts.

Comparing the effects and mechanisms of granular activated carbon and magnetite nanoparticles in dry anaerobic digestion: Focusing on microbial electron transfer and metagenomic evidence

Enhancing direct interspecies electron transfer (DIET) via granular activated carbon (GAC) and magnetite nanoparticles (MNPs) to promote methanation performance in dry anaerobic digestion (AD) systems has been extensively studied in recent years. However, the underlying mechanisms, particularly how GAC and MNPs influence DIET and extracellular polymeric substances (EPSs), remain poorly understood. In this study, the different effects and mechanisms of GAC and MNPs on dry AD fed with pig manure (PM) and corn straw were compared, with additions of 10, 20, and 50% of the volatile solid (VS) of PM. The results indicated that GAC improved the cumulative specific methane yields (CSMYs) by 18.8–20.9%, while a high dose of MNPs (50% of the VSPM) decreased the CSMY and hydrolysis rate constant by 27.0 and 75.4%, respectively. GAC provided microorganism attachment sites and functional groups for electron transfer, improving hydrolysis by enriching fermenters such as Fastidiosipila and Rikenellaceae. Nevertheless, MNPs stimulated intense dissimilatory iron reduction by Clostridium sp. in the early stage, competing with methanogens for substrates. Low and medium GAC doses (10 and 20% of the VSPM) increased the utilization of redox-active substances (e.g., humic substances and proteins) in EPS, while the high MNP dose stimulated their secretion due to microbial self-protection, impairing electron transfer. Metagenomic evidence showed that the medium GAC dose improved four methanogenic pathways and DIET mediated by microbial nanowires, while a high MNP dose impeded the final step of methanogenesis. These results provide deeper insights into the mechanisms of different conductive materials on dry AD.

Adsorption kinetics, isotherms, and selectivity of trihalomethanes and haloacetonitriles by granular activated carbon

The performance capability of granular activated carbon (GAC) adsorption in terms of disinfection by-product (DBPs) removal was investigated with synthetic water containing 1) trihalomethanes (THMs), 2) haloacetronitriles (HANs), and 3) Mix-THMs & HANs. The initial 20 min of adsorption resulted in the maximum adsorption rate, with the total THMs, total HANs, and total Mix–THMs & HANs being 4.972, 2.071, and 6.460 µg/gGAC-min, respectively. GAC dosage affects the adsorption selectivity of THMs and HANs. Under a low GAC dosage, the selectivity of GAC adsorbs more bromo-THMs than chloro-THMs. The adsorption selectivity of THMs on GAC following bromoform > dibromochloromethane > bromodichloromethane > chloroform was investigated. As the GAC concentration increased, the selectivity of THM adsorption by GAC became comparable. Chloro-HAN, in contrast to THMs, has a higher adsorption selectivity than bromo-HAN. Trichloroacetonitrile was removed by GAC more rapidly than the other HAN species when the GAC dose was increased. The toxin of bromoform was primarily eliminated through GAC adsorption, caused by a greater removal rate than that of the other THMs. As an implemented measure, GAC is introduced to reduce THMs and HANs and the toxic contents associated with THMs and HANs.

Quenching residual H2O2 from UV/H2O2 with granular activated carbon: A significant impact of bicarbonate

UV/H2O2 has been used as an advanced oxidation process to remove organic micropollutants from drinking water. It is essential to quench residual H2O2 to prevent increased chlorine demand during chlorination/chloramination and within distribution systems. Granular activated carbon (GAC) filter can quench the residual oxidant and eliminate some of the dissolved organic matter. However, knowledge on the kinetics and governing factors of GAC quenching of residual H2O2 from UV/H2O2 and the mechanism underlying the enhancement of the process by HCO3− is limited. Therefore, this study aimed to analyse the kinetics and influential factors, particularly the significant impact of bicarbonate (HCO3−). H2O2 decomposition by GAC followed first-order kinetics, and the rate constants normalised by the GAC dosage (kn) were steady (1.6 × 10−3 L g−1 min−1) with variations in the GAC dosage and initial H2O2 concentration. Alkaline conditions favour H2O2 quenching. The content of basic groups exhibited a stronger correlation with the efficiency of GAC in quenching H₂O₂ than did the acidic groups， with their specific kn values being 8.9 and 2.4 min−1 M−1, respectively. The presence of chloride, sulfate, nitrate, and dissolved organic matter inhibited H2O2 quenching, while HCO3− promoted it. The interfacial hydroxyl radical (HO•) zones were visualised on the GAC surface, and HCO3− addition increased the HO• concentration. HCO3− increased the concentration of persistent free radicals (PFRs) on the GAC surface, which mainly contributed to HO• generation. A significant enhancement of HCO3− on H2O2 quenching by GAC was also verified in real water. This study revealed the synergistic mechanism of HCO3− and GAC on H2O2 quenching and presents the potential applications of residual H2O2 in the H2O2-based oxidation processes.

Granular activated carbon optimization for enhanced environmental disaster resilience and malathion removal from agricultural effluent

The study aimed to address the critical problem of malathion pesticide contamination in agricultural runoff and its adverse impact on the environment. It specifically focused on utilizing granular activated carbon (GAC), derived from both coal (CBAC) and peat (PBAC), as a promising solution for effective malathion removal. This study focused on the substantial influence of particle size and GAC dosage on the removal efficiency of malathion. It was determined that optimal conditions, resulting in an impressive 90% removal efficiency, were achieved when the initial malathion concentration of 7 μg L-1 was reduced to approximately 1.14 μg L-1 and 1.5 μg L-1 for CBAC with particle sizes of 0.063 mm and 1.0 mm, respectively. In contrast, PBAC exhibited a removal efficiency of 2.87 μg L-1 under similar conditions. The study further employed the Langmuir and Freundlich adsorption isotherms models to analyze the adsorption behavior of malathion on GAC. The equilibrium data closely aligned with both models, and the maximum adsorption capacity was determined to be an impressive 248.1 mg g-1. These findings highlight the significant potential of GAC, whether coal or peat-based, as a highly effective absorbent material for mitigating malathion contamination in agricultural runoff. This research contributes to enhancing environmental disaster resilience by offering a viable method for optimizing GAC use, thereby reducing the detrimental effects of pesticide contamination on the environment.

Adsorption/Ozonation integration for intensified ethyl acetate plant wastewater treatment: Process optimization and sensitivity analysis assessment

For the first time, the ethyl acetate production plant wastewater was treated using a batch adsorption/ozonation integrated process. The wastewater contained alcoholic pollutants (majorly, ethanol) and the discharge of this wastewater could result in serious risks to the environment. The operational variables including reaction time (10 to 60 min), temperature (20 to 60 °C), ozone flowrate (4 to 12 L/min) and granular activated carbon (GAC) dose (5 to 15 g) were optimized by applying response surface methodology, where the removal of chemical oxygen demand (COD) was aimed to be maximized as the target variable. The optimal conditions were obtained at the reaction time of 60 min, temperature of 60 °C, GAC dose of 10 g and ozone flowrate of 8 L/min, which resulted in COD removal of 98.5 %. Characterization analyses revealed that ozonation could support in-situ regeneration of the GAC and provide a synergistic effect on the COD removal enhancement. The separation kinetics of the integrated process was also assessed and found to be superior than those of the standalone operations. Sobol sensitivity analysis results uncovered that the reaction temperature by 85 % and the binary interaction of the reaction time and temperature by near 7 % impact shares were the most effective parameters on the COD removal. Isothermal studies showed that the adsorption of ethanol on GAC is physical, multilayer and heterogeneous. Consequently, the integrated adsorption/ozonation process has been approved as a potential method for the treatment of ethyl acetate plant wastewater.

Degradation of ampicillin by combined process: Adsorption and Fenton reaction

When disposed incorrectly, antibiotics can cause complex effects on environmental matrices, such as bacterial resistance. In this context, the present work investigated the degradation and mineralization of the β -lactam antibiotic ampicillin (AMP) applying a combined treatment of Fenton reaction and adsorption onto granular activated carbon (GAC). Adsorption parameters of contact time (10–210 min) and GAC dosage (5–50 g L − 1 ) were evaluated, as well as adsorption kinetics. Both in Fenton reaction and combined process, the influence of H 2 O 2 and Fe + 2 concentrations were evaluated, using five combinations of H 2 O 2 /Fe + 2 : 300/60 μ M, 300/80 μ M, 400/70 μ M, 500/60 μ M and 500/80 μ M. Finally, because of the combined process, GAC regeneration was investigated in 3 cycles. Best adsorption conditions were determined as 150 minutes of contact time and GAC concentration of 20 g L −1 , reaching 57% of AMP removal and adsorbed amount of 0.58 mg g − 1 . All Fenton experimental conditions led to a complete degradation of AMP within 1 min, suggesting the generation rate of hydroxyl radicals was faster in the first minutes of reaction. In the combined process, similar results for degradation were found. A higher mineralization (83%) and GAC regeneration (85%) was reached at H 2 O 2 /Fe + 2 = 500 / 80 μ M, indicating the influence of H 2 O 2 and Fe + 2 concentrations. GAC regeneration efficiency for the 3 cycles were, respectively, 84%, 71% and 49%. Thus, the results demonstrate the combined process of Fenton reaction and GAC adsorption is a feasible treatment reaching high mineralization. • The combined process of adsorption and Fenton is a feasible treatment for effluents containing ampicillin reaching high mineralization. • Generation rate of hydroxyl radicals was faster in the first minutes of reaction. • Fenton promotes the granular activated carbon regeneration.

Removal of pharmaceuticals from nitrified urine

In this study, granular activated carbon (GAC) was examined for the removal of five of the most commonly detected pharmaceuticals (naproxen, carbamazepine, acetaminophen, ibuprofen and metronidazole) from a nitrified urine to make the urine-derived fertiliser nutrient safe for food crops. Batch experiments were conducted to investigate the adsorption kinetics that described the removal of micropollutants (equal concentrations of 0.2 mM) from the synthetic nitrified urine at different GAC dosages (10–3000 mg/L). Artificial neural network modelling was also used to predict and simulate the removal of pharmaceuticals from nitrified urine. Langmuir and Freundlich isotherm models described the equilibrium data, with the Langmuir model providing slightly higher correlations. At the highest dose of 3000 mg/L GAC, all the pharmaceuticals showed a removal rates of over 90% after 1 h of adsorption time and 99% removal rates after 6 h of adsorption time. This study concludes that GAC is able to remove the targeted xenobiotics without affecting the concentration of N and P in the urine, suggesting that nitrified urine could be safely used as a nutrient product in future.

Study on Chromaticity Removal from Mineral Processing Wastewater with Salicylic Hydroxamic Acid by Granular Activated Carbon Catalyzed Ozonation

Salicylic hydroxamic acid is a novel flotation reagent used in mineral processing. However, it impacts the flotation wastewater leaving behind high chromaticity which limits its reuse and affects discharge for mining enterprises. This study researched ozonation catalyzed by the granular activated carbon (GAC) method to treat the chromaticity of the simulated mineral processing wastewater with salicylic hydroxamic acid. The effects of pH value, ozone (O3) concentration, GAC dosage, and reaction time on chromaticity and chemical oxygen demand (CODCr) removal were discussed. The results of individual ozonation experiments showed that the chromaticity removal ratio reached 79% and the effluent chromaticity exceeded the requirement of reuse and discharge when the optimal experimental conditions were pH value 3, ozone concentration 6 mg/L, and reaction time 40 min. The orthogonal experimental results of catalytic ozonation with GAC on chromaticity removal explained that the chromaticity removal ratio could reach 96.36% and the chromaticity of effluent was only 20 when the optimal level of experimental parameters was pH value 2.87, O3 concentration 6 mg/L, GAC dosage 0.06 g/L, reaction time 60 min respectively. The degradation pathway of salicylic hydroxamic acid by ozonation was also considered based on an analysis with ultraviolet absorption spectrum and high-performance liquid chromatography (HPLC).

Removal and recovery of selenium species from wastewater: Adsorption kinetics and co-precipitation mechanisms

This study investigates the effectiveness of four adsorbent candidates, including nano-zerovalent iron (nZVI), magnetite (Fe3O4), ferric chloride (FeCl3) and granular activated carbon (GAC) to remove inorganic and organic selenium species from contaminated water. The efficacy of the modified co-precipitation method using a combination of ferrous and ferric chloride was also investigated. Among the adsorbents tested, ferric oxyhydroxide flocs formed by the precipitation of ferric chloride was found to be most efficient as more than 95 % of Se (VI) was removed using ferric chloride dose of 1 g/L. The optimum pH for removal of Se (VI) irrespective of the adsorbent was found to be in the range of 4.0–5.5. Comparatively, Se (IV) was removed faster and required lesser adsorbent doses for all adsorbents tested. The experimental data fitted well with Langmuir model compared to Freundlich model indicating the monolayer adsorption. While metallic adsorbents were found to show better performance for removal of inorganic selenium species, GAC showed a higher affinity towards the removal of selenomethionine, an organo-selenium compound. About 50 % of selenomethionine was removed within a contact time of one hour for GAC dose of 0.5 g/L, while about 9% and 7% removal was observed for the same doses of Fe3O4 and nZVI powders respectively. In contrast to electrostatic attraction, which is considered to be the main drive for adsorption of inorganic selenium, van der Waals attraction is supposed to drive adsorption of selenomethionine.

Towards Potential Removal of Malachite Green from Wastewater: Adsorption Process Optimization and Prediction

Granular activated carbon (GAC) is utilized as an adsorbent for the malachite green (MG) dye removal from aqueous solutions. The GAC was characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to realize the GAC chemical and physical features effects on the adsorption efficiency. Batch adsorption processes were carried out with different variables like pH, GAC dose, initial MG concentration and time. The response surface methodology (RSM) was used to design the experiments, model the adsorption process, optimize the operating conditions and predict the response. A 24 full factorial central composite design (CCD) was performed for the experimental design and the analysis of the results. Analysis of variance (ANOVA) was employed to determine the significance of the factors and explore the interaction between the various experimental parameters. An empirical model was derived to correlate the experimental results and predict the behavior of the GAC for the adsorption process. The model showed a good agreement with the experimental results of R2 = 0.9968 and evidenced that the optimum operating parameters are pH 10, 2 g GAC/L, 200 mg/L of MG initial concentration and 113 min adsorption time for complete removal of MG.

Solvent-based washing as a treatment alternative for onshore petroleum drill cuttings in Thailand

In Thailand, onshore drill cuttings (DC) contaminated with total petroleum hydrocarbon (TPH) are currently transported off-site for incineration, causing high transportation cost and potential leakage to the environment. To address the issues, we develop solvent-based washing as a greener alternative for onshore DC remediation, focusing on solvent selection, washing process optimization, and solvent recovery. The results showed that ethyl lactate (EL) was the best green solvent for DC washing, compared to water, ethylene glycol, and ethyl acetate. Based on response surface methodology assisted with central composite design, the maximum TPH removal of 87.1% was achieved from 4 mL g−1 liquid-to-solid ratio, 14 min washing time, and 80 rpm stirring speed, and the TPH removal rate by EL fitted well with the second-order reaction (R2 = 0.9774). Furthermore, the spent EL was successfully recycled by simple and low-energy adsorption using granular activated carbon (GAC). With the sufficient GAC dosage, TPH could be completely removed from the spent EL without impairing the original EL properties. Moreover, the recycled EL exhibited its successful reuse in the subsequent DC washing process. These findings suggest that solvent washing accompanied with solvent recovery by adsorption could be a novel and greener remedial scheme for onshore DC management.

Hybrid ceramic membrane reactor combined with fluidized adsorbents and scouring agents for hazardous metal-plating wastewater treatment

In this study, a ceramic membrane consisting of aluminum oxide in the support and active layer with a surface pore size of 0.1 μm was applied with a real hazardous metal-plating wastewater. Alumina membrane was submerged directly into a fluidized membrane reactor specially designed for fluidizing the granular activated carbon (GAC) particles along membrane surface by recirculating a bulk wastewater through the reactor to improve fouling control and removal efficiency of contaminants. Zeolite particle which has the similar size to the GAC was also tested to compare membrane performance. Neutralizing a wastewater pH resulted in the agglomeration of particulate and colloidal materials, leading to the significant deposit of the fouling layer on membrane surface. The external fouling layer formed on membrane surface enhanced the removal efficiency of the heavy metal ions due to its role as secondary membrane. In addition to the fouling control by mechanical scouring actions, fluidizing the GAC particles on membrane was more beneficial to improve organic removal efficiency than zeolite. The increase in GAC dosage from 10 to 30 v/v% did not result in any beneficial effect on both fouling reduction and organic removal efficiency.

Bioelectrochemical cell (BeCC) integrated with Granular Activated Carbon (GAC) in treating spent caustic wastewater

Abstract The study is to treat spent caustic wastewater by using bioelectrochemical cell (BeCC) integrated with Granular Activated Carbon (GAC) as the bacterial attachment medium. BeCC is a bioelectrochemical reactor which employed microorganisms for substrate degradation, while also capable in producing energy. The study investigated the optimum GAC dosage in BeCC whereby it was tested at 0 g (blank) to 25 g of GAC and its performance in terms of Chemical Oxygen Demand (COD) and sulfide removal and open circuit voltage (OCV) were assessed throughout 30 days of operation. From the study, GAC dosage of 10 g was the optimum GAC dosage with the highest COD and sulfide removal of 97.56% and 96.25%, respectively and highest voltage of 583 mV. Comparing the optimum BeCC performance with the blank, the result demonstrated 16% and 25% higher in COD and sulfide removal, respectively with increment of OCV from 115.7 mV to 583 mV. The biomass characteristics at different GAC dosage were indicated by the mixed liquor suspended solid (MLSS), mixed liquor volatile suspended solid (MLVSS), biomass extracellular polymeric substance (EPS) and sludge volume index (SVI). It is found that the dominant bacteria attached on the GAC was Klebsiella oxytoca identified by biochemical identification method.

Simultaneous phenol removal and electricity generation using a hybrid granular activated carbon adsorption-biodegradation process in a batch recycled tubular microbial fuel cell

A microbial fuel cell (MFC) was efficiently integrated with adsorption process to remove a hardly degradable compound (phenol). For this purpose, a tubular recycled batch bioreactor was designed as a granular activated carbon (GAC) adsorption/MFC combined system (GAMFC). Effects of three important parameters, i.e. temperature, phenol concentration, and GAC dosage, on the performance of the GAMFC were investigated. Results revealed that the GAMFC could achieve an efficiency of 95% in phenol removal at optimum conditions, which was higher than the conventional MFC (75%). Additionally, power density increased to 110 mW m−2 in the presence of GAC, while for the MFC it was only 70 mW m−2. This improvement can be attributed to the role of GAC as a porous media in facilitating microbial growth as well as its contribution as an adsorbent. Experimental results in the GAMFC were simulated using a modified multi-order- Butler-Volmer equation and the inhibitory constant was 0.456 kg m−3, which was higher than the MFC at the same condition (0.17 kg m−3). Columbic efficiency calculated for the GAMFC and the MFC at optimum conditions was 45.77% and 22.13%, respectively. Furthermore, a petrochemical wastewater containing a considerable amount of phenol was fed to the MFC and GAMFC systems, to evaluate their efficiencies in a real condition. The superior performance of the GAMFC compared to the MFC was also reconfirmed in this case.

Removing arsenic from water by coprecipitation with iron: Effect of arsenic and iron concentrations and adsorbent incorporation

Arsenic (As) contamination of drinking water is a major cause of As toxicity in many parts of the world. A study was conducted to evaluate As removal from water containing 100–700 μg/L of As and As to Fe concentration ratios of 1:5–1:1000 using the coprecipitation process with and without As/Fe adsorption onto granular activated carbon (GAC). Fe concentration required to reduce As concentrations in order to achieve the WHO standard level of 10 μg/L increased exponentially with the increase in initial As concentration. When small amounts of GAC were added to the As/Fe solutions the Fe required to remove these As concentrations reduced drastically. This decline was due to the GAC adsorption of Fe and As, enhancing the removal of these metals through coprecipitation. Predictive regression equations were developed relating the GAC dose requirement to the initial As and Fe concentrations. Zeta potential data revealed that As was adsorbed on the GAC by outer-sphere complexation whereas Fe was adsorbed by inner-sphere complexation reversing the negative charge on GAC to positive values. X-ray diffraction of the GAC samples in the presence of Fe had an additional peak characteristic of ferrihydrite (Fe oxide) compared to that of the GAC sample without Fe. The study showed that incorporating an adsorbent into the coprecipitation process has the advantage of removing As from waters at all concentrations of Fe and As compared to coprecipitation alone which does not remove As to the required levels if Fe concentration is low.

Degradation of metronidazole antibiotic in aqueous medium using activated carbon as a persulfate activator

Abstract In this work, activation of persulfate (PS) and hydrogen peroxide (H2O2) in the presence of granular activated carbon (GAC) was studied in order to investigate the degradation of Metronidazole (MTZ) antibiotic in aqueous solution. The results showed that GAC could activate PS effectively better than H2O2. Also, both adsorption and oxidation process induced MTZ removal in the GAC/PS system with remarkable synergistic effect in the combined system. After 240 min, 50% of PS was degraded and 80% of MTZ and 65% of COD were removed under the ambient conditions containing initial MTZ concentration of 100 mg L−1, PS/MTZ molar ratio of 100/1, GAC dosage of 5 g L−1 and initial pH of 3.9. Both PS degradation and MTZ removal followed pseudo first order kinetic with rate constant of 0.0006 min−1 and 0.0023 min−1, respectively. Scavenging study using methanol and phenol as a radical scavenger showed that most oxidation of MTZ occurred on the surface or in the boundary layer around catalyst. It was also found that MTZ removal efficiency increased when PS concentration or GAC dosage increased. However, results showed that PS loading is more effective than GAC dosage. The MTZ removal efficiency was still considerable after 4 runs reusability of GAC which implied in-situ regeneration of catalyst. It can be concluded that GAC is a favorable and promising metal-free catalyst for wastewater treatment utilization.

Differentiated stimulating effects of activated carbon on methanogenic degradation of acetate, propionate and butyrate

Granular activated carbon (GAC) could promote methane production from organic wastes, but a wide range of dosages has been reported. In present study, different GAC dosages of 0, 0.5, 5 and 25 g/L were supplemented into anaerobic digesters and the methanogenic degradation kinetics of acetate, propionate and butyrate were characterized, respectively. At high organic load of 5 g/L, the degradation rates of propionate and butyrate increased by 1.5–4.7 and 2.5–7.0 times at varied GAC dosages. The methane production rates (Rmax) from propionate and butyrate were significantly elevated when increasing GAC dosage up to 5 g/L. However, only a minor increment was found for acetate degradation either at 1 g/L or 5 g/L. The stimulatory mechanism of GAC for accelerated syntrophic degradation of propionate and butyrate can be primarily attributed to the triggering effect on acetogenesis, as evidenced by the enrichment of syntrophic bacteria e.g. Thermovirga, Synergistaceae, and Syntrophomonas etc.

Advanced treatment of biotreated coking wastewater with peroxymonosulfate oxidation catalyzed by granular activated carbon

AbstractBACKGROUNDAfter biological treatment, coking wastewater contains high concentrations of toxic organic contaminants and thus requires further treatment.RESULTSAdvanced treatment of biotreated coking wastewater (BTCW) with peroxymonosulfate (PMS) oxidation catalyzed by granular activated carbon (GAC) at ambient temperature (25 °C) was comprehensively investigated. The GAC/PMS system exhibited higher efficiency for total organic carbon (TOC) removal from BTCW than did the PMS‐only and GAC‐only systems. Up to 75.7% of TOC was removed over a 5 h period with 2 g L‐1 of KHSO5 and 10 g L‐1 of GAC at an initial pH of approximately 5. The TOC removal efficiency increased with PMS concentration and GAC dosage; however, the superfluous PMS was not conducive to organic degradation. The PMS decomposition followed a first‐order kinetics behavior. The GAC/PMS system's capacity for TOC removal gradually weakened with increase in the number of times the GAC was reused. Almost half of the removal rate was retained after four uses of GAC. The excitation–emission matrix fluorescence demonstrated that humic‐acid‐like substances are effectively adsorbed and preferentially decomposed in wastewater.CONCLUSIONThe study suggests that it is feasible for advanced treatment of BTCW with PMS oxidation catalyzed by GAC, achieving high efficiency for TOC removal. © 2017 Society of Chemical Industry

Phenols removal using ozonation-adsorption with granular activated carbon (GAC) in rotating packed bed reactor

Synthetic wastewater containing phenols was treated using combination method of ozonation-adsorption with GAC (Granular Activated Carbon) in a packed bed rotating reactor. Ozone reacts quickly with phenol and activated carbon increases the oxidation process by producing hydroxyl radicals. Performance parameters evaluated are phenol removal percentage, the quantity of hydroxyl radical formed, changes in pH and ozone utilization, dissolved ozone concentration and ozone concentration in off gas. The performance of the combination method was compared with single ozonation and single adsorption. The influence of GAC dose and initial pH of phenols were evaluated in ozonation-adsorption method. The results show that ozonation-adsorption method generates more OH radicals than a single ozonation. Quantity of OH radical formation increases with increasing pH and quantity of the GAC. The combination method prove better performance in removing phenols. At the same operation condition, ozonation-adsorption method is capable of removing of 78.62% phenols as compared with single ozonation (53.15%) and single adsorption (36.67%). The increasing percentage of phenol removal in ozonation-adsorption method is proportional to the addition of GAC dose, solution pH, and packed bed rotator speed. Maximum percentage of phenol removal is obtained under alkaline conditions (pH 10) and 125 g of GAC