Catalytic Ozonation with Activated Carbon for Treatment of Humic Substances in Water

2013 ◽  
Vol 470 ◽  
pp. 19-22 ◽  
Author(s):  
Hyun Soo Choi ◽  
Dong Seok Rhee

Ozonation of the ubiquitous and poorly biodegradable humic acid in aquatic system was conducted in the presence of activated carbon with the aim of catalyst. The optimum operating parameters deduced from this study was GAC amount of 16.5 v/v% (GAC column volume per reactor volume) in the humic acid solution of initial pH 9. DOC removal rate in Ozone/GAC process was higher than the sum of Ozone alone and GAC adsorption process. Formaldehyde formation in Ozone/GAC process was less than in Ozone alone and GAC adsorption process. The part of molecular size distribution under 10 k Dalton were increased in the Ozone/GAC process.

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Y. S. Mohammad ◽  
E. M. Shaibu-Imodagbe ◽  
S. B. Igboro ◽  
A. Giwa ◽  
C. A. Okuofu

Modeling of adsorption process establishes mathematical relationship between the interacting process variables and process optimization is important in determining the values of factors for which the response is at maximum. In this paper, response surface methodology was employed for the modeling and optimization of adsorption of phenol onto rice husk activated carbon. Among the action variables considered are activated carbon pretreatment temperature, adsorbent dosage, and initial concentration of phenol, while the response variables are removal efficiency and adsorption capacity. Regression analysis was used to analyze the models developed. The outcome of this research showed that 99.79% and 99.81% of the variations in removal efficiency and adsorption capacity, respectively, are attributed to the three process variables considered, that is, pretreatment temperature, adsorbent dosage, and initial phenol concentration. Therefore, the models can be used to predict the interaction of the process variables. Optimization tests showed that the optimum operating conditions for the adsorption process occurred at initial solute concentration of 40.61 mg/L, pretreatment temperature of 441.46°C, adsorbent dosage 4 g, adsorption capacity of 0.9595 mg/g, and removal efficiency of 97.16%. These optimum operating conditions were experimentally validated.


Author(s):  
Li Cong ◽  
Lingling Feng ◽  
Xinlai Wei ◽  
Jie Jin ◽  
Ke Wu

The activated carbon was prepared from sycamore bark by activation of zinc chloride. The absorbing effect of activated carbon on Congo red wastewater is studied. The characteristics of sycamore bark activated carbon were characterized by SEM and BET. The effects of adsorbent dosage, time, and shaking speed on the adsorption properties of Congo red by sycamore bark activated carbon were studied. The isotherm, kinetics, and thermodynamics of adsorption were explored. The results revealed that the activated carbon contain a large apparent mesopores. Adsorption efficiency was increased with enhancing the adsorption dosage and time. The removal rate of Conge red reached to 98.2% under room temperature with adsorbent dosage of 3.0 g/L, adsorption time of 120 min, shaking speed of 60r/min. The adsorption of Congo red on sycamore bark activated carbon was followed Langmuir isotherm model and Lagergren pseudo-second order kinetics model. The adsorption was spontaneous, endothermic, and the entropy was increasing in the adsorption process.


Author(s):  
Wei Wei ◽  
Haoyang Gong ◽  
Lin Sheng ◽  
Dong Zhou ◽  
Shuguang Zhu

Abstract Although humic acid (HA) is a complex natural organic matter, it can potentially harm the environment and human health. In this study, aluminum–air fuel cell electrocoagulation (AAFCEC) was used to remove HAs from water while generating electricity. Initial pH, electrolyte concentration, HA concentration electrode distance and external resistance were investigated to determine the power generation and removal efficiency. The results showed that the better performance of power generation has been acquired in the alkaline solution and larger electrolyte concentration and short electrode distance. Further, Al–Ferron complexation timed spectrophotometry was used to determine the Al speciation distribution in the solution under different parameters. The power density of the cell reached 313.47 mW/cm2 for the following conditions: 1 g/L NaCl concentration, 3 cm electrode distance, 20 Ω external resistor, and pH 9. After about an hour electrolysis, the optimum removal rate of HA was above 99%. The results demonstrated that the AAFCEC is an efficient and eco-friendly water treatment process, and it could be further developed and disseminated in the rural areas and households.


Author(s):  
Xiaorong Kang ◽  
Yali Liu ◽  
Can Yang ◽  
Han Cheng

Abstract Dewatered municipal sludge was used as raw material to prepare activated carbon (SAC), and the SAC was modified by walnut shell and nano-titanium dioxide (MSAC). The results showed that the MSAC had a higher specific surface area (SBET) (279.147 m2/g) and total pore volume (VT) (0.324 cm3/g) than the SAC. Simultaneously, the functional groups such as C-O, C = O, and Ti-O-Ti on the surface of MSAC were enhanced due to modification. These physicochemical properties provided prerequisites for the diffusion and degradation of pollutants in MSAC. Furthermore, the MSAC was applied to adsorb amoxicillin (AMX) from aqueous solution, in batch experiments, the maximum removal rate (88.19%) was observed at an initial AMX concentration of 30 mg/L, MSAC dosage of 5.0 g/L, pH of 8, contact time of 180 min, and temperature of 25 °C. In addition, the adsorption process was well described by the Freundlich isotherm model and pseudo-second-order kinetic model, indicating that the adsorption of AMX onto MSAC was dominated by multilayer chemisorption. Also, the adsorption thermodynamics suggested that the adsorption process of AMX onto MSAC was endothermic, feasible and spontaneous.


2013 ◽  
Vol 772 ◽  
pp. 359-364 ◽  
Author(s):  
Rong Cheng ◽  
Xiang Zheng ◽  
Guan Qing Li ◽  
Jian Long Wang

Two kinds of supported iron nanoparticles by activated carbon/carbon nanotubes were synthesized under ambient condition in this study. And their performance for pentachlorophenol (PCP) removal in water was examined. The SEM images showed that the nanoparticles supported by carbon nanotubes (Fe-CNTs) were of better dispersibility and smaller particle size than that by activated carbon (Fe-C). And the iron content in both of Fe-CNTs and Fe-C system measured by EDS was similar to each other. But the removal rate of PCP in the former system was obviously lower than the latter. It might be due to the more excellent adsorption capacity of activated carbon. And another main reason could be the reduction of adsorption sites due to the occupation of iron nanoparticles. The removal of PCP from the solution was the result of both of the activated carbon/carbon nanotubes adsorption and iron degradation. And the adsorption process was prior to the degradation by iron nanoparticles.


2010 ◽  
Vol 62 (6) ◽  
pp. 1304-1311 ◽  
Author(s):  
Huaili Zheng ◽  
Huiqin Zhang ◽  
Xiaonan Sun ◽  
Peng Zhang ◽  
Tiroyaone Tshukudu ◽  
...  

Catalytic oxidation of malachite green using the microwave-Fenton process was investigated. 0% of malachite green de-colorization using the microwave process and 23.5% of malachite green de-colorization using the Fenton process were observed within 5 minutes. In contrast 95.4% of malachite green de-colorization using the microwave-Fenton was observed in 5 minutes. During the microwave-Fenton process, the optimum operating conditions for malachite green de-colorization were found to be 3.40 of initial pH, 0.08 mmol/L of Fe2 +  concentration and 12.5 mmol/L of H2O2 concentration. Confirmatory tests were carried out under the optimum conditions and the COD removal rate of 82.0% and the de-colorization rate of 99.0% were observed in 5 minutes. The apparent kinetics equation of −dC/dt = 0.0337 [malachite green]0.9860[Fe2 + ]0.8234[H2O2]0.1663 for malachite green de-colorization was calculated, which implied that malachite green was the dominant factor in determining the removal efficiency of malachite green based on microwave-Fenton process.


2012 ◽  
Vol 610-613 ◽  
pp. 1710-1717
Author(s):  
Gui Zhong Zhou ◽  
Xuan Wang ◽  
Zhao Feng Wang ◽  
Shu Qing Pan ◽  
Shao Xiang Li

The activated carbon fiber(ACF) electrodes were prepared for electrosorption desalination. The electrodes were analyzed using scanning electron microscope (SEM), and the desalting efficiency was represented by the removal rate of Cl-. As a result, desalting efficiency decreases with increasing initial concentration of Cl-, whereas the total adsorption capacity increases. The most suitable voltage for electrosorption desalination is 1.2 ~ 1.4V. The electrosorption desalination achieves the best results while the distance between two electrodes is 1.0cm. Electrosorption plays a more important role in the adsorption process compared with physical adsorption. The removal rate of Cl- is obviously improved by using ACF electrode modified by HNO3 and KOH and desalination ratio of the electrode treated with KOH is increased by 16.5%. Therefore, the ACF electrode would be suitable for using in the application of electrosorption desalination.


2015 ◽  
Vol 14 (3) ◽  
pp. 576-582 ◽  
Author(s):  
M. Bekbolet ◽  
S. Sen-Kavurmaci

Photocatalytic oxidation leads to a drastic change in excitation emission matrix (EEM) fluorescence features of humic acid molecular size fractions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nurul Umairah M. Nizam ◽  
Marlia M. Hanafiah ◽  
Ebrahim Mahmoudi ◽  
Azhar A. Halim ◽  
Abdul Wahab Mohammad

AbstractIn this study, two biomass-based adsorbents were used as new precursors for optimizing synthesis conditions of a cost-effective powdered activated carbon (PAC). The PAC removed dyes from an aqueous solution using carbonization and activation by KOH, NaOH, and H2SO4. The optimum synthesis, activation temperature, time and impregnation ratio, removal rate, and uptake capacity were determined. The optimum PAC was analyzed and characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), Zeta potential, and Raman spectroscopy. Morphological studies showed single-layered planes with highly porous surfaces, especially PAC activated by NaOH and H2SO4. The results showed that the experimental data were well-fitted with a pseudo-second-order model. Based on Langmuir isotherm, the maximum adsorption capacity for removing methylene blue (MB) was 769.23 mg g−1 and 458.43 mg g−1 for congo red (CR). Based on the isotherm models, more than one mechanism was involved in the adsorption process, monolayer for the anionic dye and multilayer for the cationic dye. Elovich and intraparticle diffusion kinetic models showed that rubber seed shells (RSS) has higher α values with a greater tendency to adsorb dyes compared to rubber seed (RS). A thermodynamic study showed that both dyes’ adsorption process was spontaneous and exothermic due to the negative values of the enthalpy (ΔH) and Gibbs free energy (ΔG). The change in removal efficiency of adsorbent for regeneration study was observed in the seventh cycles, with a 3% decline in the CR and 2% decline in MB removal performance. This study showed that the presence of functional groups and active sites on the produced adsorbent (hydroxyl, alkoxy, carboxyl, and π − π) contributed to its considerable affinity for adsorption in dye removal. Therefore, the optimum PAC can serve as efficient and cost-effective adsorbents to remove dyes from industrial wastewater.


Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 608
Author(s):  
Aixin Yu ◽  
Yuankun Liu ◽  
Xing Li ◽  
Yanling Yang ◽  
Zhiwei Zhou ◽  
...  

As a key parameter in the adsorption process, removal rate is not available under most operating conditions due to the time and cost of experimental testing. To address this issue, evaluation of the efficiency of NH4+ removal from stormwater by coal-based granular activated carbon (CB-GAC), a novel approach, the response surface methodology (RSM), back-propagation artificial neural network (BP-ANN) coupled with genetic algorithm (GA), has been applied in this research. The sorption process was modeled based on Box-Behnben design (BBD) RSM method for independent variables: Contact time, initial concentration, temperature, and pH; suggesting a quadratic polynomial model with p-value < 0.001, R2 = 0.9762. The BP-ANN with a structure of 4-8-1 gave the best performance. Compared with the BBD-RSM model, the BP-ANN model indicated better prediction of the response with R2 = 0.9959. The weights derived from BP-ANN was further analyzed by Garson equation, and the results showed that the order of the variables’ effectiveness is as follow: Contact time (31.23%) > pH (24.68%) > temperature (22.93%) > initial concentration (21.16%). The process parameters were optimized via RSM optimization tools and GA. The results of validation experiments showed that the optimization results of GA-ANN are more accurate than BBD-RSM, with contact time = 899.41 min, initial concentration = 17.35 mg/L, temperature = 15 °C, pH = 6.98, NH4+ removal rate = 63.74%, and relative error = 0.87%. Furthermore, the CB-GAC has been characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET). The isotherm and kinetic studies of the adsorption process illustrated that adsorption of NH4+ onto CB-GAC corresponded Langmuir isotherm and pseudo-second-order kinetic models. The calculated maximum adsorption capacity was 0.2821 mg/g.


Sign in / Sign up

Export Citation Format

Share Document