Efficient Removal of Cr(VI) from Water by Biochar and Activated Carbon Prepared through Hydrothermal Carbonization and Pyrolysis: Adsorption-Coupled Reduction Mechanism

Three carbonaceous porous materials (biochar and activated carbon) were developed from the Tectona grandis tree sawdust. The applied process of two-stage preparation included pre-treatment through hydrothermal carbonization at 190 °C and subsequent pyrolysis at 800 °C. Two chemical activating agents (K2CO3 and ZnCl2) were used to prepared activated carbons (K2CO3-AC and ZnCl2-AC), respectively. They were characterized by textural property, morphology, and surface element components and applied to remove Cr(VI) from solution at various solution pH values and initial Cr(VI) concentrations. Results showed that the textural parameters (SBET and VTotal) of the prepared material were 1757 m2/g and 1.027 cm3/g for Zn-Cl2-AC, 1013 m2/g and 0.418 cm3/g for K2CO3-AC, and 792 m2/g and 0.345 cm3/g for biochar. The adsorption process reached the highest efficiency at pH 3.0. The Langmuir maximum adsorption capacity indicated the decreasing order: ZnCl2-AC (127 mg/g) > K2CO3-AC (103 mg/g) > biochar (83.5 mg/g). The removal mechanism of Cr(V) from solution was regarded as an adsorption-coupled reduction, namely (1) partial reduction of Cr(VI) into Cr(III) during the adsorption process and (2) adsorption of the Cr(VI) anions through electrostatic attraction and pore filling and the reduced Cr(III) cations through complexation, Cπ–cation interaction, cation exchange, and pore filing. Therefore, the prepared biochar and activated carbon can server as promising adsorbents to efficiently remove both Cr(VI) and Cr(III) from water.

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Potential Use of Waste Activated Sludge Hydrothermally Treated as a Renewable Fuel or Activated Carbon Precursor

Molecules ◽

10.3390/molecules25153534 ◽

2020 ◽

Vol 25 (15) ◽

pp. 3534

Author(s):

J. A. Villamil ◽

E. Diaz ◽

M. A. de la Rubia ◽

A. F. Mohedano

Keyword(s):

Activated Carbon ◽

Activated Sludge ◽

Activated Carbons ◽

Chemical Activation ◽

Hydrothermal Carbonization ◽

Effect Of Temperature ◽

Waste Activated Sludge ◽

Maximum Adsorption Capacity ◽

Porous Network ◽

Good Potential

In this work, dewatered waste activated sludge (DWAS) was subjected to hydrothermal carbonization to obtain hydrochars that can be used as renewable solid fuels or activated carbon precursors. A central composite rotatable design was used to analyze the effect of temperature (140–220 °C) and reaction time (0.5–4 h) on the physicochemical properties of the products. The hydrochars exhibited increased heating values (up to 22.3 MJ/kg) and their air-activation provided carbons with a low BET area (100 m2/g). By contrast, chemical activation with K2CO3, KOH, FeCl3 and ZnCl2 gave carbons with a well-developed porous network (BET areas of 410–1030 m2/g) and substantial contents in mesopores (0.079–0.271 cm3/g) and micropores (0.136–0.398 cm3/g). The chemically activated carbons had a fairly good potential to adsorb emerging pollutants such as sulfamethoxazole, antipyrine and desipramine from the liquid phase. This was especially the case with KOH-activated hydrochars, which exhibited a maximum adsorption capacity of 412, 198 and 146 mg/g, respectively, for the previous pollutants.

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Oxytetracycline Adsorption from Aqueous Solutions on Commercial and High-Temperature Modified Activated Carbons

Energies ◽

10.3390/en14123481 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3481

Author(s):

Joanna Lach ◽

Agnieszka Ociepa-Kubicka ◽

Maciej Mrowiec

Keyword(s):

Activated Carbon ◽

Aqueous Solutions ◽

Activated Carbons ◽

Electricity Consumption ◽

Solution Ph ◽

Carbon Modification ◽

Modification Method ◽

Flow Through ◽

Proposed Modification ◽

Modified Activated Carbons

The aim of the work was to evaluate the possibility of using commercial and modified activated carbons for the removal of oxytetracycline from aqueous solutions. The kinetics and statics of adsorption as well as the effect of the activated carbon dose and solution pH on the efficiency of the oxytetracycline adsorption were analyzed. Based on the study of oxytetracycline adsorption isotherms, the activated carbons were ranked in the following order: F-300 > WG-12 > Picabiol > ROW08 > WACC 8 × 30 > F-100 > WAZ 0.6–2.4. The most effective activated carbons were characterized by large specific surfaces. The best matching results were obtained for: Redlich–Peterson, Thot and Jovanovic models, and lower for the most frequently used Freundlich and Langmuir models. The adsorption proceeded better from solutions with pH = 6 than with pH = 3 and 10. Two ways of modifying activated carbon were also assessed. A proprietary method of activated carbon modification was proposed. It uses the heating of activated carbon as a result of current flow through its bed. Both carbons modified at 400 °C in the rotary kiln and on the proprietary SEOW (Joule-heat) modification stand enabled to obtain adsorbents with higher and comparable monolayer capacities. The advantage of the proposed modification method is low electricity consumption.

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Removal of Ni (II) from Aqueous Solution by Adsorption onto Activated Carbon Prepared from Lapsi (Choerospondias axillaris) Seed Stone

Journal of the Institute of Engineering ◽

10.3126/jie.v9i1.10680 ◽

2014 ◽

Vol 9 (1) ◽

pp. 166-174 ◽

Cited By ~ 9

Author(s):

Rajeshwar M. Shrestha ◽

Margit Varga ◽

Imre Varga ◽

Amar P. Yadav ◽

Bhadra P. Pokharel ◽

...

Keyword(s):

Aqueous Solution ◽

Activated Carbon ◽

Activated Carbons ◽

Low Cost ◽

Chemical Characterization ◽

Maximum Adsorption Capacity ◽

Adsorption Data ◽

Optimum Ph ◽

Nickel Adsorption

Activated carbons were prepared from Lapsi seed stone by the treatment with H2SO4 and HNO3 for the removal of Ni (II) ions from aqueous solution. Two activated carbon have been prepared from Lapsi seed stones by treating with conc.H2SO4 and a mixture of H2SO4 and HNO3 in the ratio of 1:1 by weight for removal of Ni(II) ions. Chemical characterization of the resultant activated carbons was studied by Fourier Transform Infrared Spectroscopy and Boehm titration which revealed the presence of oxygen containing surface functional groups like carboxyl, lactones and phenols in the carbons. The optimum pH for nickel adsorption is found to be 5. The adsorption data were better fitted with the Langmuir equations than Freundlich adsorption equation to describe the equilibrium isotherms. The maximum adsorption capacity of Ni (II) on the resultant activated carbons was 28.25.8 mg g-1 with H2SO4 and 69.49 mg g-1 with a mixture of H2SO4 and HNO3. The waste material used in the preparation of the activated carbons is inexpensive and readily available. Hence the carbons prepared from Lapsi seed stones can act as potential low cost adsorbents for the removal of Ni (II) from water. DOI: http://dx.doi.org/10.3126/jie.v9i1.10680Journal of the Institute of Engineering, Vol. 9, No. 1, pp. 166–174

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Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

10.20944/preprints201908.0076.v1 ◽

2019 ◽

Author(s):

Lorena Alcaraz ◽

María Esther Escudero ◽

Francisco J. Alguacil ◽

Irene Llorente ◽

Ana Urbieta ◽

...

Keyword(s):

Adsorption Capacity ◽

Activated Carbons ◽

Chemical Study ◽

Bet Surface Area ◽

Maximum Adsorption Capacity ◽

Solution Ph ◽

Microporous Material ◽

Physico Chemical ◽

Spent Coffee Ground ◽

Coffee Ground

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m2·g-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g-1 and 33.52 mg·g-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

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Removal of Methylene blue, Escherichia coli and Pseudomonus aeruginosa by Adsorption Process of Activated Carbon Produced from Moringa oleifera Bark

Malaysian Journal of Science Health & Technology ◽

10.33102/mjosht.v7i.105 ◽

2021 ◽

Author(s):

Md. Shahin Azad ◽

Syaza Azhari ◽

Mohd Sukri Hassan

Keyword(s):

Escherichia Coli ◽

Methylene Blue ◽

Activated Carbon ◽

Moringa Oleifera ◽

Adsorption Process ◽

Diffusion Mechanism ◽

Bacterial Load ◽

Batch Adsorption ◽

Maximum Adsorption Capacity ◽

E Coli

The utilization of biopolymer derived from Moringa oleifera bark using ZnCl2 and H2SO4 as activating agents for eliminating Methylene blue, Escherichia coli and Pseudomonas aeruginosa from producing wastewater. In this study, Methylene blue and both bacteria were effectively adsorbed by activated carbon with lowest dosage. The activated carbon was prepared from natural-by product of Moringa oleifera bark by pyrolysis in a furnace at 700°C for 1 h. The characteristics of activated carbon have been determined using Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET), pHzpc (zero point charge), and FTIR spectroscopy. The obtained result were closely fitted with Freundlich isotherm model and adsorption kinetics follow the pseudo-second order model with the highest value of correlation coefficient (R2~1). Adsorption quantity was dose dependent and bacteria were maximum adsorbed using 10 mg of activated carbon as well as 25mg for methylene blue. The maximum adsorption capacity showed within 1 hour. The bacterial load was reduced by 98% for E. coli, 96% for P. aeruginosa as well as methylene blue reduced 94.2% from aqueous solution using batch adsorption methods. Adsorption process controlled by film diffusion mechanism. These result proposed that the activated carbon of Moringa oleifera can be used as a good adsorbent for the removal of Methylene blue, E. coli and P. aeruginosa.

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Activated Carbon from Winemaking Waste: Thermoeconomic Analysis for Large-Scale Production

Energies ◽

10.3390/en13236462 ◽

2020 ◽

Vol 13 (23) ◽

pp. 6462

Author(s):

Isaac Lorero ◽

Arturo J. Vizcaíno ◽

Francisco J. Alguacil ◽

Félix A. López

Keyword(s):

Activated Carbon ◽

Heat Exchangers ◽

Large Scale ◽

Activated Carbons ◽

Hydrothermal Carbonization ◽

Thermodynamic Efficiency ◽

Physical Activation ◽

Scale Production ◽

Production Scale ◽

Costs Analysis

An activated carbon manufacturing process from winemaking waste is analyzed. In that way, vine shoots conversion is studied as a basis for plant designing, and mass and energy balances of hydrothermal carbonization and physical activation are fulfilled. To develop an energy-integrated plant, a network of heat exchangers is allocated to recover heat waste, and a cogeneration cycle is designed to provide electricity and remaining heat process demands. Furthermore, thermoeconomic analysis is applied to determine the thermodynamic efficiency and the economic viability of the plant. Energy balance indicates that heat exchangers energy integration covers 48.9% of the overall demands by crossing hot and cold streams and recovering heat from residual flue gas. On the other hand, the exergy costs analysis identifies combustion of pruning wood as the main source of exergy destruction, confirming the suitability of the integration to improve the thermodynamic performance. Attending to economic costs analysis, production scale and vineyard pruning wood price are identified as a critical parameter on process profitability. With a scale of 2.5 ton/h of pruning wood carbonization, a break-event point to compete with activated carbons from biomass origin is reached. Nevertheless, cost of pruning wood is identified as another important economic parameter, pointing out the suitability of wet methods such as hydrothermal carbonization (HTC) to treat them as received form the harvest and to contribute to cutting down its prices.

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Efficient Removal of Diclofenac from Aqueous Solution by Potassium Ferrate-Activated Porous Graphitic Biochar: Ambient Condition Influences and Adsorption Mechanism

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17010291 ◽

2019 ◽

Vol 17 (1) ◽

pp. 291 ◽

Cited By ~ 6

Author(s):

Nguyen Thi Minh Tam ◽

Yunguo Liu ◽

Hassan Bashir ◽

Zhihong Yin ◽

Yuan He ◽

...

Keyword(s):

Aqueous Solution ◽

Adsorption Capacity ◽

Diclofenac Sodium ◽

Maximum Adsorption Capacity ◽

Potassium Ferrate ◽

Solution Ph ◽

Modified Biochar ◽

Prepared Material ◽

Endothermic Process ◽

One Step

Porous graphitic biochar was synthesized by one-step treatment biomass using potassium ferrate (K2FeO4) as activator for both carbonization and graphitization processes. The modified biochar (Fe@BC) was applied for the removal of diclofenac sodium (DCF) in an aqueous solution. The as-prepared material possesses a well-developed micro/mesoporous and graphitic structure, which can strengthen its adsorption capacity towards DCF. The experimental results indicated that the maximum adsorption capacity (qmax) of Fe@BC for DCF obtained from Langmuir isotherm simulation was 123.45 mg·L−1 and it was a remarkable value of DCF adsorption in comparison with that of other biomass-based adsorbents previously reported. Thermodynamic quality and effect of ionic strength studies demonstrated that the adsorption was a endothermic process, and higher environmental temperatures may be more favorable for the uptake of DCF onto Fe@BC surface; however, the presence of NaCl in the solution slightly obstructed DCF adsorption. Adsorption capacity was found to be decreased with the increase of solution pH. Additionally, the possible mechanism of the DCF adsorption process on Fe@BC may involve chemical adsorption with the presence of H-bonding and π–π interaction. With high adsorption capacity and reusability, Fe@BC was found to be a promising absorbent for DCF removal from water as well as for water purification applications.

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Application of Carbonaceous Materials to Phenol Removal from Aqueous Solution by Adsorption

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.164.297 ◽

2012 ◽

Vol 164 ◽

pp. 297-301 ◽

Cited By ~ 1

Author(s):

Wei Fang Dong ◽

Li Hua Zang ◽

Qing Chao Gong ◽

Cun Cun Chen ◽

Cai Hong Zheng ◽

...

Keyword(s):

Activated Carbon ◽

Adsorption Capacity ◽

Petroleum Coke ◽

Granular Activated Carbon ◽

Powdered Activated Carbon ◽

Maximum Adsorption Capacity ◽

Phenol Removal ◽

Carbonaceous Materials ◽

Solution Ph ◽

Equilibrium Studies

Low cost carbonaceous materials were evaluated for their ability to remove phenol from wastewater. The effects of adsorbents dosage, contact time and maximum adsorption capacity were investigated for granular activated carbon, powdered activated carbon, petroleum coke and multi-walled carbon nanotube (MWNT). Equilibrium studies were conducted in 50mg/L initial phenol concentration, solution pH of 5 and at temperature of 23°C. The results showed the adsorption process was fast and it reached equilibrium in 3 h. Petroleum coke and MWNT had poor adsorption which could reach the removal efficiency of phenol with 43.18% and 36.64% respectively. The granular activated carbon possessed good adsorption ability to phenol with 96.40% at the optimum dosage 5g and optimum time 90min.The powdered activated carbon was an effective adsorbent with a maximum adsorption capacity of 42.32 mg/g.

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Performance of Sweet Potato’s Leaf-Derived Activated Carbon for Hydrogen Sulphide Removal from Biogas

Journal of Energy ◽

10.1155/2020/9121085 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Geni Juma ◽

Revocatus Machunda ◽

Tatiana Pogrebnaya

Keyword(s):

Activated Carbon ◽

Adsorption Process ◽

Activated Carbons ◽

Chemical Activation ◽

Carbonization Temperature ◽

Optimal Test ◽

Potato Leaf ◽

Bet Analysis ◽

S 100 ◽

Activation Ratio

In this study, sweet potato leaf activated carbon (SpLAC) was prepared by the chemical activation method using KOH and applied as an adsorbent for H2S removal from biogas. The study focused on the understanding of the effect of carbonization temperature (Tc), varying KOH : C activation ratio, flow rate (FR) of biogas, and mass of SpLAC on sample adsorption capacity. The BET analysis was performed for both fresh and spent activated carbons as well as for carbonized samples, which were not activated; also, the activated carbon was characterized by XRF and CHNS techniques. The results showed that removal efficiency (RE) of the SpLAC increased with increase carbonization temperature from 600 to 800°C and the mass of sorbent from 0.4 g to 1.0 g. The optimal test conditions were determined: 1.0 g of sorbent with a KOH : C ratio of 1 : 1, Tc=800°C, and FR=0.02 m3/h which resulted in a sorption capacity of about 3.7 g S/100 g of the SpLAC. Our findings corroborated that H2S removal was contributed not only by the adsorption process with the pore available but also by the presence of iron in the sample that reacted with H2S. Therefore, upon successful H2S sorption, SpLAC is suggested as a viable adsorbent for H2S removal from biogas.

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Adsorption of MIB by activated carbons produced using several activation techniques

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0178 ◽

2002 ◽

Vol 2 (5-6) ◽

pp. 265-270

Author(s):

R. McCallum ◽

F. Roddick ◽

M. Hobday

Keyword(s):

Heat Treatment ◽

Activated Carbon ◽

Water Treatment ◽

Organic Compounds ◽

Activated Carbons ◽

Alkali Treatment ◽

Power Station ◽

Steam Activation ◽

Pre Treatment ◽

Physical And Chemical

Water treatment authorities use activated carbon as the best available technology to remove low molecular weight organic compounds from potable water. In Australia, pollutants of concern include secondary metabolites from bacterial and cyanobacterial blooms which are highly odorous and, in some cases, toxic. Of these compounds, 2-methylisoborneol (MIB) is one of the most common and its unpleasant musty earthy odour can be detected at or above approximately 10 ng/L. Difficulties in using activated carbon to target such small organic compounds arise when the water has high concentrations of natural organic matter (NOM), as these compounds also adsorb on activated carbon. The adsorption of NOM on activated carbon increases the cost of using this material in water treatment due to competition with the target organic compounds, reducing the capacity of the activated carbon for the latter. The surface of activated carbon can be tailored during production to provide physical and chemical characteristics that can either aid or hinder the adsorption of particular compounds. One source of activated carbon currently under investigation at RMIT University is brown coal char waste from power stations. This waste, currently disposed of to landfill, is potentially an option for activated carbon production. This material has the advantage that it has already been carbonised at around 500°C in the power generation process. This means that less energy is required to produce activated carbon from power station char compared to coal, making the final product cheaper to produce. Previous work at RMIT has shown that steam activated power station char can remove organic compounds from water. Production of a range of activated carbons from power station char (PSC) was undertaken using different activation methods, including steam activation, steam activation with acid pre-treatment, alkali heat treatment, and Lewis acid heat treatment. The different activation methods produced activated carbons with different pore size distributions, in particular, the acid pre-treatment increased the surface area and porosity significantly compared with steam activation, and the alkali treatment increased the microporosity. Adsorption of MIB on these activated carbons was evaluated to determine the relationship between physical and chemical interactions of the activated carbon and adsorption. Adsorption of MIB on these activated carbons was found to be dependent on the secondary micropore volume. Lewis acid treatment and alkali treatment was not involved in the generation of many of these secondary pores, hence carbons from these treatments did not perform well in adsorption tests. The best adsorption results were achieved with steam activated or acid treated steam activated samples which performed comparably to commercial products. Initial results showed that competition from NOM adsorption was lowest with the PSC activated carbons, allowing greater adsorption of MIB, compared with the commercial activated carbons.

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