Regeneration of Activated Carbons Spent by Waste Water Treatment Using KOH Chemical Activation

Park, Jung Eun; Lee, Gi Bbum; Hong, Bum Ui; Hwang, Sohyun

doi:10.3390/app9235132

Cited by 43 publications

(23 citation statements)

References 31 publications

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“…This was justified by the higher SSA and pore volume obtained with the CCA, suggesting that the steaming process cleared the pores of ash and allowed better N 2 adsorption than its nonactivated counterpart. This agrees with the work of Park et al [48] who reported that activation flushes out ash from the pore spaces leading to increased nitrogen adsorption.…”

Section: Bet Surface Area Isothermssupporting

confidence: 93%

Electricity generation in microbial fuel cell from wet torrefaction wastewater and locally developed corncob electrodes

et al. 2021

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Corncob pyrochar activated with steam (CCA) and nonactivated corncob pyrochar (NCC) were produced and characterized. The performance of the best material was tested in a dual-chambered microbial fuel cell (MFC) as an electrode for bioelectricity generation using wet torrefaction wastewater as substrate. Pyrolysis of 80.3 g of dried corncobs was carried out at 600 • C under a constant N 2 flow of 3 L min −1 for 30 min and the resulting pyrochar was activated using steam also at 600 • C. Voltage and current outputs from the MFC were recorded daily for 18 days. The proximate and Brunauer-Emmett-Teller (BET) surface area analyses revealed that CCA had the highest fixed carbon content of 71.9 % and higher surface area of 104.0 m 2 g −1 respectively. A larger pore diameter of 1.9 × 10 −3 µm was also recorded with the CCA than 1.2 × 10 −3 µm for NCC. The MFC produced a maximum power output of 21.5 mW. The physicochemical analyses of the wastewater effluent revealed an increased electrical conductivity from 1724 to 3460 µS cm −1 with a significant decrease by 91.9% in the total organic carbon (TOC) from 3700 to 298 mg L −1 . Steam activation increases the surface area, porosity, stability and redox reversibility of the corncob pyrochar. Therefore, steam-activated corncob pyrochar performed well in MFCs due to the high power output observed. K E Y W O R D Sbiobased corncob pyrochar, electrodes in MFC, power output of MFC, steam activation, wastewater This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Section: Bet Surface Area Isothermssupporting

confidence: 93%

Electricity generation in microbial fuel cell from wet torrefaction wastewater and locally developed corncob electrodes

et al. 2021

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“…Furthermore, porosity in the range of mesopores facilitates the regeneration process of spent materials and the further multiple usage. The methods of regeneration most applied comprise wet oxidation, elution with suitable solvent, microwave or thermal regeneration [ 48 ]. The regeneration of adsorbents is important taking into account the assumptions of environmental sustainability and economic effectiveness [ 49 , 50 ].…”

Section: Introductionmentioning

confidence: 99%

Mesoporous Carbons of Well-Organized Structure in the Removal of Dyes from Aqueous Solutions

et al. 2021

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Mesoporous carbons with differentiated properties were synthesized by using the method of impregnation of mesoporous well-organized silicas. The obtained carbonaceous materials and microporous activated carbon were investigated by applying different methods in order to determine their structural, surface and adsorption properties towards selected dyes from aqueous solutions. In order to verify applicability of adsorbents for removing dyes the equilibrium and kinetic experimental data were measured and analyzed by applying various equations and models. The structural and acid-base properties of the investigated carbons were evaluated by Small-Angle X-ray Scattering (SAXS) technique, adsorption/desorption of nitrogen, potentiometric titration, and Transmission Electron Microscopy (TEM). The results of these techniques are complementary, indicating the type of porosity and structural ordering, e.g., the pore sizes determined from the SAXS data are in good agreement with those obtained from nitrogen sorption data. The SAXS and TEM data confirm the regularity of mesoporous carbon structure. The adsorption experiment, especially kinetic measurements, reveals the utility of mesoporous carbons in dye removing, taking into account not only the adsorption uptake but also the adsorption rate.

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“…Moreover, to enhance the adsorption capability of hydrochar, modification turned out to be an effective method [14]. By "modification" we mean a treatment in which the feedstock (hydrochar in this case) is treated with a chemical agent (e.g., KOH) via impregnation, which is not followed by a heat treatment at 500-850 • C in nitrogen typical of chemical activation [11,[15][16][17]. For instance, Regmi et al [18] tested the sorption capacities of KOH-modified hydrochar from switchgrass for removing copper and cadmium from aqueous solutions: they found a removal of about 100% within 24 h of contact time while the raw hydrochar only removed 16% of copper and 5.6% of cadmium.…”

Section: Introductionmentioning

confidence: 99%

Sewage Sludge Hydrochar: An Option for Removal of Methylene Blue from Wastewater

et al. 2020

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Municipal sewage sludge was subjected to a hydrothermal carbonization (HTC) process for developing a hydrochar with high adsorption capacity for water remediation in terms of dye removal. Three hydrochars were produced from municipal sewage sludge by performing HTC at 190, 220 and 250 °C, with a 3 h reaction time. Moreover, a portion of each hydrochar was subjected to a post-treatment with KOH in order to increase the adsorption capacity. Physicochemical properties of sludge samples, raw hydrochars and KOH-modified hydrochars were measured and batch adsorption studies were performed using methylene blue (MB) as a reference dye. Data revealed that both raw and modified hydrochars reached good MB removal efficiency for solutions with low MB concentrations; on the contrary, MB in high concentration solutions was efficiently removed only by modified hydrochars. Interestingly, the KOH treatment greatly improved the MB adsorption rate; the modified hydrochars were capable of capturing above 95% of the initial MB amount in less than 15 min. The physicochemical characterization indicates that alkali modification caused a change in the hydrochar surface making it more chemically homogeneous, which is particularly evident for the 250 °C hydrochar. Thus, the adsorption process can be regarded as a complex result of various phenomena, including physi- and chemi-sorption, acid–base and redox equilibria.

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Regeneration of Activated Carbons Spent by Waste Water Treatment Using KOH Chemical Activation

Cited by 43 publications

References 31 publications

Electricity generation in microbial fuel cell from wet torrefaction wastewater and locally developed corncob electrodes

Electricity generation in microbial fuel cell from wet torrefaction wastewater and locally developed corncob electrodes

Mesoporous Carbons of Well-Organized Structure in the Removal of Dyes from Aqueous Solutions

Sewage Sludge Hydrochar: An Option for Removal of Methylene Blue from Wastewater

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