Improved methods for carbon adsorption studies for water and wastewater treatment (original) (raw)
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Selecting activated carbon for water and wastewater treatability studies
Environmental Progress, 2007
A series of follow-up investigations were performed to produce data for improving the four-indicator carbon selection method that we developed to identify high-potential activated carbons effective for removing specific organic water pollutants. The carbon's pore structure and surface chemistry are dependent on the raw material and the activation process. Coconut carbons have relatively more small pores than large pores; coal and apricot nutshell/walnut shell fruit carbons have the desirable pore structures for removing adsorbates of all sizes. Chemical activation, excessive activation, and/or thermal reactivation enlarge small pores, resulting in reduced phenol number and higher tannic acid number. Activated carbon's phenol, iodine, methylene blue, and tannic acid numbers are convenient indicators of its surface area and pore volume of pore diameters <10, 10-15, 15-28, and >28 A˚, respectively. The phenol number of a carbon is also a good indicator of its surface acidity of oxygen-containing organic functional groups that affect the adsorptive capacity for aromatic and other small polar organics. The tannic acid number is an indicator of carbon's capacity for large, high-molecular-weight natural organic precursors of disinfection by-products in water treatment. The experimental results for removing nitrobenzene, methyl-tert-butyl ether, 4,4-bisphenol, humic acid, and the organic constituents of a biologically treated coking-plant effluent have demonstrated the effectiveness of this capacity-indicator-based method of carbon selection. A comprehensive table of iodine, phenol, methylene blue, and tannic numbers of common activated carbons is a useful database to environmental professionals for selecting few high-potential activated carbons to be evaluated in an efficient water/wastewater treatability study.
Environmental Progress, 2007
A simple and cost-effective method for conducting adsorption breakthrough experiments in a microsize carbon column is proposed; it is much faster than the conventional methods. Relative to the existing microcolumn rapid breakthrough (MCRB) methods, this method employs simplified procedure, low cost and readily available pump, sampler, and piping and fittings to allow its practice in an ordinary environmental laboratory. The efficient MCRB method may be employed to identify the best granular activated carbon, to verify its treatment effectiveness, and to estimate its capacity utilization rate and the adsorption treatment cost. The effects of particle size and empty bed contact time on MCRB test results were determined. The validity and benefits of this MCRB method were demonstrated by the adsorption breakthrough data for phenol, red dye X3B, tannic acid, MTBE, 2,4-dichrophenol, and the organic pollutants in a biologically treated coking plant effluent. 2007
2017
Activated carbon is versatile adsorbent which has extraordinarily large specific surface area, high degree of surface reactivity and tunable chemical and porous structure. Due to its remarkable properties, activated carbon find utility in many applications including environmental remediation, adsorptive removal of color and odor, catalysis, solvent recovery, energy storage, recovery of precious metals and biomedical application. In this paper, the application of activated carbons towards drinking water purification and wastewater treatment will be discussed. Different organic and inorganic chemicals are being discharged into water bodies from untreated urban and rural sanitary and domestic waste, release of toxic industrial and pharmaceutical effluents and runoff from agricultural fields and municipal corporations. This causes the pollution of ground and surface water making it unfit for drinking purpose. The contamination of water due to organic pollutants is serious issue due to t...
Polish Journal of Environmental Studies
The current study seeks to investigate the feasibility use of date palm kernels for the development of activated carbon (AC) towards its application, which functions as an adsorbent to treat oil-contaminated groundwater. Biochar derived from date palm kernels (BPK), was prepared by direct pyrolysis of the raw precursor at 600ºC for 90 minutes (in oxygen-limited condition). Activated carbon (ACPK) included similar pyrolysis conditions of biochar with subsequent impregnation in H 2 SO 4 (as activating agent) at a ratio of acid: biochar (1:1), moderate temperature. The analytical approach was performed through the use of XRD, BET, and FTIR, techniques to evaluate the effect of carbonization and activation process in improving the adsorptive properties of starting materials. Carbonaceous adsorbents obtained were highly porous due to their elevated specific surface area of (333.4 m²/g for BPK and 741.5 m²/g for ACPK) and their amorphous structure. Indeed, the textural proprieties were significantly improved by the acidic treatment. Further, the adsorption behavior of produced materials was tested by performing batch adsorption tests in contaminated water samples using a ratio of 1:1 (g/L) for 24 hours. The efficiency of adsorbents was evaluated by COD (C0 = 8568 mg/L), BOD 5 (C0 = 200 mg/L) concentration, pH and hardness values before and after the treatment. Removal efficiency of COD for the BPK and ACPK samples reached 82.6% and 95.2% respectively, while for BOD 5 was the same (97.0%) for both adsorbents. Additionally, the treated water sample has the same excellent class suitable for irrigation applications according to the Wilcox diagram. In consequence,
Agricultural Engineering International: The CIGR Journal, 2020
Pharmaceutical wastes are emerging organic contaminants, mostly unregulated and on the increase. This study evaluates the potential of low-cost activated carbons derived from bamboo in remediating Pharmaceutical actives contaminants (PhACs) and compared with Oclansorb. Two species of bamboos were processed into activated carbons using ZnCl 2 , KCl, and H 3 PO 4 . Selections of the bamboo adsorbents were based on porosity and surface area using BET analysis. Batch adsorption process was used with contact time as bench mark for comparison. Carbonized Bambusa vulgaris (CBV350 O C H 3 PO 4 ) has the highest surface area (SPAS) of 30.1342 m 2 /g when compared to other adsorbents while carbonized Oxythenantera abyssinica (COA 350 O C KCl) gave the highest pore size (AAPW) 446.4384(A). CBV (350 O C H 3 PO 4 ) gave type IV isotherm classification which favors mono and multilayer adsorption as compared to others adsorbents that obeys the type III isotherm classification . COA with KCl activ...
Activated Carbon as Adsorbent In Advance Treatement of Wastewater
IOSR Journal of Mechanical and Civil Engineering, 2017
A treatability study was carried out on wastewater collected from Bhandewadi Wastewater treatment plant, Nagpur, Maharashtra. The aim of the research work was to check out whether the activated carbon (AC) gives maximum removal of BOD, COD, pH, Turbidity from wastewater sample. The present research work was undertaken to find out percentage of activated carbon is more efficient for removing the characteristics of wastewater like BOD, COD for safe disposal in water streams and land. The raw wastewater is put under contact of activated carbon and checked the efficiency of the activated carbon for reducing down the harmful parameters. The wastewater is given an exposure to activated carbon at 2%, 4% and 6% for 7 and 14 days.
DESALINATION AND WATER TREATMENT
Water contamination by heavy metals and organic waste presents a great challenge in developing countries, thereby hampering access to safe water. In this work, activated carbons were prepared from Zea mays cob (MC), Anacardium occidentale (cashew nut shells-CNS), sawdust from Pinus oocarpa (SPO) and Pterocarpus angolensis (SPA) biomass waste found in Zambia. The activated carbons were used as filters to remove heavy metals and organic pollutants from aqueous solution. The average adsorption efficiency of heavy metals was 99.10 ± 0.6%, 99.38 ± 0.4%, 98.43 ± 0.6% and 99.40 ± 0.4% for SPA, SPO, CNS and MC, respectively. Adsorption was found to follow Langmuir model for CNS and Freundlich model for SPA, SPO and MC. The adsorbent with high adsorption efficiency of heavy metals, MC was characterized using Fourier-transform infrared spectroscopy and further tested for methylene blue (MB) removal by adsorption. The kinetic data for adsorption of MB were best fitted by the pseudo-second-order kinetic model. The highest percentage removal of MB at equilibrium was 99.69 ± 0.3% at 50 mg/L and the lowest was 96.47 ± 0.1% at 350 mg/L indicating that maize cob activated carbon is an excellent adsorbent in the removal methylene blue and heavy metals even at low concentrations.
Use of carbon materials for produced water treatment: a review on adsorption process and performance
International Journal of Environmental Science and Technology, 2021
The oil and gas production is identified by consuming a large amount of water and generating massive produced water. The produced water is either reinjected into the underground layers or released into the rivers and oceans that can cause severe damage to the environment due to toxic elements such as salts, oil and grease, and polyaromatic hydrocarbons. So produced water treatment and management can reduce the significant threats to the soil and water resources and solve the lack of water in different water-consuming sectors. During the last decades, adsorption methods, such as using expanded graphite and activated carbon materials, have attracted scientists' attention because these adsorbents are cost-effective and practical. This study aimed to review expanded graphite's synthesis, adsorption process, and efficient factors in removing heavy oil, heavy metals, benzene, toluene, ethylbenzene, and xylenes, and organic acids from produced water and compare with other adsorbents, including activated carbon and residual biomass. Based on the results of extensive research works, expanded graphite's high adsorption feature suggested that graphite can be a promising adsorbent in actual produced water treatment.