“…5). This observation is consistent with our earlier study on rambutan seed ACs and other studies [5, 62, 70]. Fig.…”
Section: Resultssupporting
confidence: 94%
“…1 showed a shift, broadening and disappearance of the peaks after activation of the adsorbent. The disappearance of some functional groups in the adsorbent reveals that the functional groups are unstable due to increase in temperature during the activation process [61, 62] . Table 3 shows the comparative features of absorption bands for each FTIR spectra of RLBP and ALBP with their differences and various assignments.…”
Activated carbon prepared from
locust bean
husk was modified using ortho-phosphoric acid (ALBP) and used to scavenge Rhodamine B (RhB) dye from aqueous solutions. Characteristic features of the adsorbents were investigated using SEM, FTIR, pH
pzc
and Boehm Titration (BT) techniques respectively. Batch studies were used to determine the influences of contact time, temperature and initial Rh–B dye concentrations. Adsorption data were analysed using four different isotherm models. The maximum monolayer adsorption capacity of 1111.1 mgg
-1
was obtained for RhB dye adsorption. The kinetics of the adsorption process was studied using pseudo-first-order, pseudo-second-order Elovich and intraparticle diffusion models respectively. The experimental data was best described by pseudo-second-order kinetic model. Favourability of the process of adsorption was also established by the separator factor (R
L
) value ranging from 0 and 1, while the mean energy of adsorption (E
a
) was 1.12 kJmol
-1
suggesting that the removal of Rh–B dye from aqueous solution followed a physisorption process. For the thermodynamic investigations, the positive values of ΔS (280.956 Jmol
−1
K
−1
) indicates the affinity of adsorbent for the Rh–B dye uptake and increase randomness at the solid–solution interface during adsorption of Rh–B dye onto the surface of the active sites of ALBP. The negative value of ΔG (-31.892 to -26.355 kJmol
-1
) depicts the spontaneity and feasibility of the adsorption process. The cost analysis provides a simple proof that ALBP (42.52 USD per kg) is approximately six times cheaper than Commercial Activated Carbon, CAC (259.5 USD per kg). The present study therefore established the suitability of ALBP for effective removal of Rh–B dye from aqueous solutions.
“…5). This observation is consistent with our earlier study on rambutan seed ACs and other studies [5, 62, 70]. Fig.…”
Section: Resultssupporting
confidence: 94%
“…1 showed a shift, broadening and disappearance of the peaks after activation of the adsorbent. The disappearance of some functional groups in the adsorbent reveals that the functional groups are unstable due to increase in temperature during the activation process [61, 62] . Table 3 shows the comparative features of absorption bands for each FTIR spectra of RLBP and ALBP with their differences and various assignments.…”
Activated carbon prepared from
locust bean
husk was modified using ortho-phosphoric acid (ALBP) and used to scavenge Rhodamine B (RhB) dye from aqueous solutions. Characteristic features of the adsorbents were investigated using SEM, FTIR, pH
pzc
and Boehm Titration (BT) techniques respectively. Batch studies were used to determine the influences of contact time, temperature and initial Rh–B dye concentrations. Adsorption data were analysed using four different isotherm models. The maximum monolayer adsorption capacity of 1111.1 mgg
-1
was obtained for RhB dye adsorption. The kinetics of the adsorption process was studied using pseudo-first-order, pseudo-second-order Elovich and intraparticle diffusion models respectively. The experimental data was best described by pseudo-second-order kinetic model. Favourability of the process of adsorption was also established by the separator factor (R
L
) value ranging from 0 and 1, while the mean energy of adsorption (E
a
) was 1.12 kJmol
-1
suggesting that the removal of Rh–B dye from aqueous solution followed a physisorption process. For the thermodynamic investigations, the positive values of ΔS (280.956 Jmol
−1
K
−1
) indicates the affinity of adsorbent for the Rh–B dye uptake and increase randomness at the solid–solution interface during adsorption of Rh–B dye onto the surface of the active sites of ALBP. The negative value of ΔG (-31.892 to -26.355 kJmol
-1
) depicts the spontaneity and feasibility of the adsorption process. The cost analysis provides a simple proof that ALBP (42.52 USD per kg) is approximately six times cheaper than Commercial Activated Carbon, CAC (259.5 USD per kg). The present study therefore established the suitability of ALBP for effective removal of Rh–B dye from aqueous solutions.
“…The obtained high "C" values depict an enhanced adsorption capacity. This observation agreed well with the existing literature (Tan et al 2008;Bello et al 2017b;Ojedokun and Bello 2017;Khasri et al 2018).…”
This study investigates the efficacy of acid activated coconut husk (CHA) for the removal of rhodamine-B (Rh-B) dye from aqueous solutions. The CHA prepared was characterized using various techniques: SEM, FTIR EDX, Boehm titration and pH pzc , respectively. The effects of different operational parameters including initial concentration, contact time and solution temperatures were examined. Kinetic data for Rh-B dye adsorption onto CHA fitted best to pseudo-second-order kinetic model considering the correlation regression (R 2 ) and the sum of squares of error values. Adsorption data were fitted to Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. Langmuir isotherm was the most fitted among all the models used with maximum monolayer sorption capacity of 1666.67 mg g −1 and the highest regression value of 0.99 indicating that CHA has greater affinity for Rh-B dye adsorption due to increased pore development via acid activation. Thermodynamic studies revealed an endothermic adsorption process with the ΔH 0 value of 62.77 kJ mol −1 . Spontaneity was ascertained based on the negative values of ΔG o (ranging from − 26.38 kJ mol −1 to − 20.93 kJ mol −1 ). The positive value of ΔS 0 (0.276 kJ mol −1 K −1 ) suggests increased randomness that exists between CHA and Rh-B dye. Cost analysis results revealed that CHA is six times cheaper than commercial activated carbon (CAC), providing a savings of 217 US$ kg −1 . CHA adsorbent was found to be suitable for Rh-B dye removal from aqueous solution.
“…A lower ash content of 3.86% was obtained for LGLAC. In accordance with observations from literature, the lower ash content signifies the applicability of the material as good adsorbent for dye adsorption while higher ash content reduce the performance and efficiency of the adsorbent for dye removal [89][90][91][92][93][94] . Fig.…”
Lemongrass leaf based activated carbon (LGLAC) was prepared using physico-chemical methods for methyl red (MR) dye removal from aqueous solutions. The surface chemistry of LGLAC before adsorption revealed the presence of different functional groups: O-H, C-H, C = O, CH 3 , C = C, NO , CO and C-N which were shifted after methyl red dye adsorption. Brunauer-Emmett-Teller surface and mesopore areas are 836.04 m 2 /g and 598.6 04 m 2 /g, whereas, the average pore diameter and total pore volume of LGLAC are 3.62 nm and 0.472 cm 3 /g respectively. Batch adsorption was studied using different parameters: initial dye concentrations (25-500 mg/L), contact time (0-24 h), solution temperature (30-60 °C) and solution pH (2-12). Adsorption of methyl red dye was observed to increase with increase in initial dye concentration, contact time and solution temperature. The methyl red dye adsorption uptake and percentage removal at equilibrium showed that the adsorption process is majorly dependent on the initial dye concentration. Optimum percentage of methyl red dye removed was observed at pH 2. The adsorption process of methyl red dye onto LGLAC was endothermic in nature. Thermodynamic parameters, including entropy change (S 0), enthalpy change (H 0), and Gibbs free energy change (G 0) were evaluated. The adsorption process was endothermic and the mechanism followed a physisorption process.
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