scholarly journals Mesoporous Carbon from Optimized Date Stone Hydrochar by Catalytic Hydrothermal Carbonization Using Response Surface Methodology: Application to Dyes Adsorption

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Faiçal El Ouadrhiri ◽  
Majda Elyemni ◽  
Amal Lahkimi ◽  
Abdelhadi Lhassani ◽  
Mehdi Chaouch ◽  
...  

Providing efficient and environmental friendly ways to recover lignocellulosic waste remains a challenge around the world. In this study, citric acid-catalyzed hydrothermal carbonization (CHTC) was coupled with pyrolysis to convert date seed (Ds) into adsorbent material. In this regard, a central composite design (CCD) using response surface methodology (RSM) was developed to examine the influence of temperature, reaction time, and catalyst dose on the mass yield (Ym(%)) and carbon retention rate (CRR(%)) in the produced hydrochars. The optimized hydrochar (OHC-Ds) was obtained under optimal conditions (200°C, 120 min, 20 mg) and characterized by a Ym(%) and CRR(%) of 59.71% and 75.84%, respectively. Chemical activation by KOH of OHC-Ds followed by pyrolysis at 600°C resulted in an active material (AOHC-Ds) rich in carbon and characterized by a high specific surface area of 1251.5 m2/g, with the dominance of mesopores, as well as an amorphous structure comparable to graphite shown by X-ray diffraction (XRD) analysis. Adsorption experiments of two dyes on AOHC-Ds showed a high maximum adsorption capacity (Qm) of 657.89 mg g−1 for methylene blue (MB) and 384.61 mg g−1 for methyl orange (MO) compared to other conventional adsorbents. This result is due to the low acidity (pHpzc) of the surface of AOHC-Ds, which equals 6.75, and its surface, which is also rich in oxygenated functional groups such as (-OH), (C=O), and (C-O) shown by FTIR analysis. These results suggest that the coupling of CHTC and KOH activation followed by pyrolysis is an encouraging way to prepare an efficient and inexpensive adsorbent to remove dyes in wastewater.

2017 ◽  
Vol 75 (9) ◽  
pp. 2047-2055 ◽  
Author(s):  
Thuan Van Tran ◽  
Quynh Thi Phuong Bui ◽  
Trinh Duy Nguyen ◽  
Van Thi Thanh Ho ◽  
Long Giang Bach

The present study focused on the application of response surface methodology to optimize the fabrication of activated carbon (AC) from sugarcane bagasse for adsorption of Cu2+ ion. The AC was synthesized via chemical activation with ZnCl2 as the activating agent. The central composite design based experiments were performed to assess the individual and interactive effect of influential parameters, including activation temperature, ZnCl2 impregnation ratio and activation time on the AC yield and removal of Cu2+ ion from the aqueous environment. The statistically significant, well-fitting quadratic regression models were successfully developed as confirmed by high F- and low P-values (<0.0001), high correlation coefficients and lack-of-fit tests. Accordingly, the optimum AC yield and removal efficiency of Cu2+ were predicted, respectively, as 48.8% and 92.7% which were approximate to the actual values. By applying the predicted optimal parameters, the AC shows a surprisingly high surface area of around 1,500 m2/g accompanied by large pore volume and narrow micropore size at low fabrication temperature.


2011 ◽  
Vol 213 ◽  
pp. 427-431 ◽  
Author(s):  
Li Jiang ◽  
Fei Ma ◽  
Ai Jun Gu ◽  
Li Jun Zhang

Activated carbon(AC)were prepared from lignin by chemical activation with sodium hydroxide(NaOH). The influence of activation temperature,activation time and impregnation ration on the BET surface areas were investigated. Based on the central composite design (CCD) and response surface methodology(RSM),the optimized technological parameters were as follows: temperature 751°C, time 57min and impregnation ration 2.06, BET surface areas was up to 1437.20 m2/g.The adequacy of the model equation for predicting the optimum response values was verified effectively by the validation.


2020 ◽  
Vol 3 (03) ◽  
pp. 44-53
Author(s):  
Mohammad Reza Rezaei Kahkha ◽  
Gholamreza Ebrahimzadeh ◽  
Ahmad Salarifar

Antibiotics and pharmaceutical products cannot remove by conventional sewage treatment. In this work, an effective adsorbent magnetic multiwalled carbon nanotube (Fe3O4@MWCNTs) was synthesized by co-precipitation of MWCNTs with Fe3O4 and used for removal of Metronidazole from aqueous solutions. Response surface methodology on central composition design (CCD) was applied for designing of experiments and building of models for Metronidazole removal before a determination by HPLC. Four factors including pH, the adsorbent dose, time, and temperature were studied and used for the quadratic equation model to the prediction of optimal points.  By solvent the equation and considering the regression coefficient (R2 =0.9997), the optimal points obtained as follows: pH =2.98; adsorbent dosage =2.16 g; time =22 min and temperature = 37.9 o C. The isotherm study of adsorption showed that the metronidazole adsorption on Fe3O4@MWCNTs follows the Langmuir model. The maximum adsorption capacity (AC) is 215 mg g-1 obtained from Langmuir isotherm.


Author(s):  
Divya Bisht ◽  
Surbhi Sinha ◽  
Sonal Nigam ◽  
Kavya Bisaria ◽  
Tithi Mehrotra ◽  
...  

Abstract In the present study, adsorption of colour and other pollutants from agro-based paper mill effluent onto fabricated coal fly ash nanoparticles (CFA-N) have been investigated. Response surface methodology was applied to evaluate the operational conditions for maximum ouster of colour from effluent by nano structured CFA-N. Maximum reduction in colour (92.45%) and other pollutants were obtained at optimum conditions: 60 min interaction time, 60 g/l adsorbent dosage and 80 rpm agitation rate. The regression coefficient values (adjusted R2= 0.7169; predicted R2= 0.7539) established harmony between predicted and the experimental data. The adsorption equilibrium results matched perfectly with both Langmuir and Freundlich isotherms with maximum adsorption capacity of 250 Pt-Co/g. Additionally, the efficacy of CFA-N was also assessed in a continuous column mode. Further, the feasibility of treated effluent for irrigation purpose was checked by growing the plant of Solanum lycopersicum. Overall, the findings demonstrated the outstanding role of inexpensive and abundantly available CFA-N in treatment of paper mill effluent to the required compliance levels.


2019 ◽  
Vol 70 (2) ◽  
pp. 410-416 ◽  
Author(s):  
Tagne Tiegam Rufis Fregue ◽  
Ioana Ionel ◽  
Anagho Solomon Gabche ◽  
Alin-Cristian Mihaiuti

Avocado seeds based activated carbon was prepared using chemical activation method which consisted of potassium hydroxide treatment. The main factors influencing the preparation of activated carbons at the calcination temperature, the concentration of the activating agent and the duration of calcination were investigated. One used as a mathematical model the response surface methodology to correlate the response. The significant factors identified by the analysis of variance (ANOVA) through the t-test, the Pareto diagram and the diagrams of surfaces. The optimum avocado seeds based activated carbon was obtained by using calcination temperature of 450 oC, concentration of activating agent of 0.3 mol/L and time of calcination of 3.0 h, which resulted to an avocado seed based activated carbon iodine number remove of 1142.1 mg/g and yield of 75.09 %, by mass. The best activated carbon obtained under the previous conditions and the raw biomass was characterized by Fourier transform infrared and Scanning Electronic Microscope.


Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3534
Author(s):  
J. A. Villamil ◽  
E. Diaz ◽  
M. A. de la Rubia ◽  
A. F. Mohedano

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.


2016 ◽  
Vol 14 (5) ◽  
pp. 991-1001 ◽  
Author(s):  
Areeb Shehzad ◽  
Mohammed J.K. Bashir ◽  
Sumathi Sethupathi ◽  
Jun-Wei Lim

Abstract The present work reveals the preparation and optimization of sea mango based activated carbon (SMAC) by microwave induced KOH activation for the adsorptive removal of organic and inorganic contaminants from the mature anaerobic landfill leachate using response surface methodology (RSM) technique. Chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N) are the main indicators for organic and inorganic compounds often found in aged landfill leachate. Hence, the treatment of this stabilized landfill leachate is considered to be an essential step prior to its discharge. The leachate sample was collected from Sahom Landfill site in Perak, Malaysia and the initial concentrations of COD and NH3-N were measured as 550 mg/L and 3,330 mg/L, respectively. The feasibility of converting Sea mango to activated carbon process to remove the COD and NH3-N pollutants from landfill leachate was investigated. The preparation conditions such as microwave heating at power range (350–600 W), impregnation of AC with KOH (0.5–3.0) and retention time (6–10 min) were evaluated, analyzed and optimized using response surface methodology (RSM). From the analysis of variance (ANOVA), the optimum conditions for preparation of SMAC was at 560 W of activation power, 8.4 min of activation time and 2.10 of impregnation ratios with higher adsorptive removal of COD (72.50 %), and NH3-N (79.77 %), respectively. The physical and chemical properties of SMAC were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and surface area. The findings exemplified the applicability of SMAC as an effective precursor for the simultaneous removal of organic and inorganic pollutants from mature landfill leachate.


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 933
Author(s):  
Xiaojian Li ◽  
Renjian Deng ◽  
Zhie Tang ◽  
Saijun Zhou ◽  
Xing Zeng ◽  
...  

Environmental pollution caused by excessive Sb(III) in the water environment is a global issue. We investigated the effect of processing parameters, their interaction and mechanistic details for the removal of Sb(III) using an iron salt-modified biosorbent (Fe(III)-modified Proteus cibarius (FMPAs)). Our study evaluated the optimisation of the adsorption time, adsorbent dose, pH, temperature and the initial concentration of Sb(III). We use response surface methodology to optimize this process, determining optimal processing conditions and the adsorption mechanism evaluated based on isotherm model and adsorption kinetics. The results showed that—(1) the optimal conditions for the adsorption of Sb(III) by FMPAs were an adsorption time of 2.2 h, adsorbent dose of 3430 mg/L, at pH 6.0 and temperature 44.0 °C. For the optimum initial concentration of Sb(III) 27.70 mg/L, the removal efficiency of Sb(III) reached 97.60%. (2) The adsorption process for Sb(III) removal by FMPAs conforms to the Langmuir adsorption isotherm model, and its maximum adsorption capacity (qmax) is as high as 30.612 mg/g. A pseudo-first-order kinetic model provided the best fit to the adsorption process, classified as single layer adsorption and chemisorption mechanism. (3) The adsorption of Sb(III) takes place via the hydroxyl group in Fe–O–OH and EPS–Polyose–O–Fe(OH)2, which forms a new complex Fe–O–Sb and X≡Fe–OH. The study showed that FMPAs have higher adsorption capacity for Sb(III) than other previously studied sorbents and with low environmental impact, it has a great potential as a green adsorbent for Sb(III) in water.


2021 ◽  
Vol 25 (1) ◽  
pp. 631-639
Author(s):  
Maris Klavins ◽  
Linda Ansone-Bertina ◽  
Lauris Arbidans ◽  
Linards Klavins

Abstract To address the biomass waste processing problem and transform it into refractory forms of carbon, recently suggested hydrothermal carbonization (HTC) of biomass in alkaline environment can be considered as a prospective and climate neutral approach. Biomass HTC provides possibilities to obtain form of biochar (hydrochar) and artificial humic substances, however the conditions of the HTC have not been much studied. Optimization by Response Surface Methodology of the HTC using microwave treatment with three experimental variables (treatment temperature, length of microwave treatment, amount of biomass per volume) provides the possibility to significantly increase the yield of humic substances at the same time reducing the duration of the treatment. However, with an increase in the yield of humic substances, the yield of hydrochar decreases, thus supporting possibilities to obtain most needed biomass waste processing product.


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