Optimized Removal of Hydroquinone and Resorcinol by Activated Carbon Based on Shea Residue (Vitellaria paradoxa): Thermodynamics, Adsorption Mechanism, Nonlinear Kinetics, and Isotherms
Abstract:The present work demonstrates the adsorption of hydroquinone (HQ) and resorcinol (R) by activated carbon based on shea residue (Vitellaria paradoxa). The adsorbent was prepared chemically by impregnation with sulfuric acid and coded by the acronym CAK-S. The central composite design (CCD) was used to optimize the main factors that influence the adsorption of HQ or R by activated carbon such as the initial concentration, the pH of the solution, the contact time, and the mass of the carbon on the expected respon… Show more
“…This favours the formation of ACs of large specific surface areas and a marked increase in the porosity. These results are in agreement with those obtained by Amola et al [15]. Figure 2( a ) Pareto diagram of CRP and ( b ) Pareto diagram of CRB.Figure 3Response surface of CRB ( a ) concentration and time with fixed temperature 400°C and ( b ) iodine number according to the temperature and time with a fixed concentration of 1 mol l −1 .Figure 4Response surface of CRP ( a ) concentration and time with fixed temperature 400°C and ( b ) iodine number according to the temperature and time with a fixed concentration of 1 mol l −1 .…”
Section: Resultssupporting
confidence: 94%
“…This favours the formation of ACs of large specific surface areas and a marked increase in the porosity. These results are in agreement with those obtained by Amola et al [15]. According to figures 2-4, it is also found that the concentration of the activating agents has a significant effect on the microporosity of said carbons; however, this factor is positive for the adsorption of iodine on CRP and negative on the CRB.…”
Section: Experimental Designsupporting
confidence: 92%
“…This peak is not pronounced on the spectra of the prepared ACs. This can be explained by the fact that chemical activation and carbonization have contributed to the breaking of these bonds and thus promote the formation of oxygenated functional groups [15], the peaks observed at 1914 cm −1 are attributed to the C–O bond stretching vibrations of ketones. Between 2137 and 2230 cm −1 the vibration bands observed are attributed to the presence of O–C–O groups or phosphanate groups.…”
Section: Resultsmentioning
confidence: 99%
“…In this work, chemical activation has been used because of its lower energy consumption and well-developed porosity of AC obtained. Activating agents which are generally used are phosphoric acid (H 3 PO 4 ) [15]; sulfuric acid [16]; zinc chloride [17]; potassium hydroxide [18]; sodium hydroxide (NaOH) [19] and iron (II) sulfate heptahydrate [20]. Herein, H 3 PO 4 and NaOH were used for the preparation of the ACs.…”
From recent research, lignocellulosic materials assert themselves as good precursors for the manufacture of highly carbonaceous and porous materials. Hence, the perspective of this work is the preparation of the low-cost activated carbons (ACs) based on puck shells (
Afrostyrax lepidophyllus
) with a large surface area. To achieve this, chemical activation using phosphoric acid and sodium hydroxide as an activating agent was carried out. The response surface methodology through Box–Behnken design was used to optimize the preparation conditions. Box–Behnken design was used to optimize the preparation conditions. The factors whose influences have been studied are the concentration of activating agent (0.5–1.5 mol l
−1
), the carbonization temperature (300–500°C) and the residence time (30–100 min). The AC obtained by phosphoric acid was named CRP and impregnated with sodium hydroxide CRB. The ideal conditions for the preparation of the ACs obtained from the maximum iodine number (647.29 for CRP and 575.15 mg g
−1
for CRB) were: 1.5 mol l
−1
for the concentration of activating agent at a carbonization temperature of 500°C during 62 min for CRP and 0.85 mol l
−1
for the concentration of activating agent at a carbonization temperature of 500°C during 59 min for CRB. These two materials prepared were characterized by several techniques pH at the point of zero charge (pHpzc), Boehm titration, Fourier transform infrared spectroscopy, XRD analysis, BET method, Raman spectroscopy and scanning electron microscopy, which confirmed the acidic nature of CRP and the basic nature of CRB carbons. The specific surface of the micropores was 509.05 and 27.53 m
2
g
−1
, respectively. It provides a new valorization of agricultural waste for the preparation of effective-cost microporous ACs as an adsorbent that can be applied in water treatment industries.
“…This favours the formation of ACs of large specific surface areas and a marked increase in the porosity. These results are in agreement with those obtained by Amola et al [15]. Figure 2( a ) Pareto diagram of CRP and ( b ) Pareto diagram of CRB.Figure 3Response surface of CRB ( a ) concentration and time with fixed temperature 400°C and ( b ) iodine number according to the temperature and time with a fixed concentration of 1 mol l −1 .Figure 4Response surface of CRP ( a ) concentration and time with fixed temperature 400°C and ( b ) iodine number according to the temperature and time with a fixed concentration of 1 mol l −1 .…”
Section: Resultssupporting
confidence: 94%
“…This favours the formation of ACs of large specific surface areas and a marked increase in the porosity. These results are in agreement with those obtained by Amola et al [15]. According to figures 2-4, it is also found that the concentration of the activating agents has a significant effect on the microporosity of said carbons; however, this factor is positive for the adsorption of iodine on CRP and negative on the CRB.…”
Section: Experimental Designsupporting
confidence: 92%
“…This peak is not pronounced on the spectra of the prepared ACs. This can be explained by the fact that chemical activation and carbonization have contributed to the breaking of these bonds and thus promote the formation of oxygenated functional groups [15], the peaks observed at 1914 cm −1 are attributed to the C–O bond stretching vibrations of ketones. Between 2137 and 2230 cm −1 the vibration bands observed are attributed to the presence of O–C–O groups or phosphanate groups.…”
Section: Resultsmentioning
confidence: 99%
“…In this work, chemical activation has been used because of its lower energy consumption and well-developed porosity of AC obtained. Activating agents which are generally used are phosphoric acid (H 3 PO 4 ) [15]; sulfuric acid [16]; zinc chloride [17]; potassium hydroxide [18]; sodium hydroxide (NaOH) [19] and iron (II) sulfate heptahydrate [20]. Herein, H 3 PO 4 and NaOH were used for the preparation of the ACs.…”
From recent research, lignocellulosic materials assert themselves as good precursors for the manufacture of highly carbonaceous and porous materials. Hence, the perspective of this work is the preparation of the low-cost activated carbons (ACs) based on puck shells (
Afrostyrax lepidophyllus
) with a large surface area. To achieve this, chemical activation using phosphoric acid and sodium hydroxide as an activating agent was carried out. The response surface methodology through Box–Behnken design was used to optimize the preparation conditions. Box–Behnken design was used to optimize the preparation conditions. The factors whose influences have been studied are the concentration of activating agent (0.5–1.5 mol l
−1
), the carbonization temperature (300–500°C) and the residence time (30–100 min). The AC obtained by phosphoric acid was named CRP and impregnated with sodium hydroxide CRB. The ideal conditions for the preparation of the ACs obtained from the maximum iodine number (647.29 for CRP and 575.15 mg g
−1
for CRB) were: 1.5 mol l
−1
for the concentration of activating agent at a carbonization temperature of 500°C during 62 min for CRP and 0.85 mol l
−1
for the concentration of activating agent at a carbonization temperature of 500°C during 59 min for CRB. These two materials prepared were characterized by several techniques pH at the point of zero charge (pHpzc), Boehm titration, Fourier transform infrared spectroscopy, XRD analysis, BET method, Raman spectroscopy and scanning electron microscopy, which confirmed the acidic nature of CRP and the basic nature of CRB carbons. The specific surface of the micropores was 509.05 and 27.53 m
2
g
−1
, respectively. It provides a new valorization of agricultural waste for the preparation of effective-cost microporous ACs as an adsorbent that can be applied in water treatment industries.
“…e use of biomass waste for the preparation of porous activated carbon has increased considerably in recent years. Some of the residual biomasses used for the manufacture of activated carbons are coffee waste [9], tucumã seeds [10], Ayous sawdust and Cucurbitaceae peelings [12], rice and coffee husks [13], olives stones and cotton cake [14], Vitellaria paradoxa [15], and rice hull and tamarind (T. indica) seeds [16].…”
In the quest for a sustainable environment and clean water resources, the efficacy of activated carbons synthesized from Garcinia cola nut shells impregnated with KOH (CBK1/1) and ZnCl2 (CBZ1/1) for the adsorption of indigo carmine (IC) dye was studied using the batch technique. The prepared activated carbons were characterized using iodine number, elemental analysis, scanning electron microscopy (SEM), FTIR spectroscopy, powder X-ray diffraction (XRD), TGA/DTA, Boehm titration, and pH at point of zero charge. The elemental analysis showed a high percentage of carbon in both activated carbons (ACs). FTIR and Boehm titration analysis indicated the presence of several functional groups on the surfaces of both ACs which could influence the adsorption of IC. The primary adsorption mechanisms involved electrostatic interaction, hydrogen bonds formation, and π−π interactions. Maximum adsorption capacity values obtained using the Fritz–Schlunder III three-parameter model were 19.019 mg·g−1 and 18.299 mg·g−1 for CBK1/1 and CBZ1/1, respectively. The Fritz–Schlunder model exponent mFS of value less than 1 showed that the adsorption of IC by the ACs occurred on heterogeneous surfaces. Positive values of ∆Q obtained by the linear and nonlinear forms of the Temkin model indicate the exothermic character of the adsorption process.
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