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The present study explores the usage of acetic-acid-treated cobalt-modified activated carbon as an adsorbent material for the adsorptive desulfurization of DBT-containing model oil. Modification of granular activated carbon (GAC) with acetic acid treatment and incorporation of cobalt species in GAC framework significantly improved its adsorption capacity by improving oxygen-containing functional groups and acidic sites. The surface area of GAC improved from 257 to 393.8 m2/g when it was treated with cobalt species and acid. The average size of the Co3O4crystallites in the Co-loaded activated carbon was found to be 13.8 nm. The effect of various operating parameters such as cobalt loading, adsorbent dose, temperature, and time was studied. Furthermore, the reusability of spent adsorbent and the effect of the presence of other aromatics compounds were also investigated. Under optimized operating conditions, ∼92% of DBT removal was achieved. The equilibrium data of DBT adsorption were analyzed by Langmuir, Freundlich, Temkin, and Redlich and Peterson (R–P) isotherm models by using nonlinear regression analysis. Among these, the Redlich–Peterson model is the best fit to represent the experimental data. The adsorption of DBT was found to be endothermic in nature. Values of changes in entropy and heat of adsorption were estimated to be 0.177 kJ/(mol K) and 35.67 kJ/mol, respectively. Moreover, a possible adsorption mechanism of DBT was also proposed. Finally, it can be concluded that cobalt-incorporated acetic-acid-activated GAC proves to be a potential adsorbent for the removal DBT from fuel oil in an economic and ecofriendly way.

The present study aims to examine the effectiveness of the catalytic wet peroxidation (CWPO) process for the removal of pyridine bearing wastewater by nanoscale zero-valent iron. In this study, nanoscale zero-valent iron was dispersed uniformly on granular activated carbon (GAC) with the help of chemical reduction method under ethanol atmosphere. N2adsorption-desorption study demonstrates the possibility of the existence of slit pores in dominant form. The surface area (SBET) of the GAC decreased significantly after nFe0loading on to the GAC channel to 191 m2/g. Catalytic wet peroxidation process was optimized by examine the influencing experimental parameters such as pH, catalyst dose, hydrogen peroxide and temperature. During CWPO process pyridine and TOC removal with time courses of 300 min at 333 K were evaluated and reached maximum removal 93% and 78%, respectively. Pyridine degradation kinetics followed the two-step first-order kinetics. The activation energy for the first-step and second-step of the oxidation process of pyridine was 33.5 kJ/mol and 19.1 kJ/mol, respectively.

The present research article depicts the adsorptive denitrogenation of indole-containing model oil using cobalt-incorporated acid-activated carbon (Co-MAC). The active metal incorporated acetic acid-activated bio-sorbent showed a significant adsorption capacity for indole from model fuel oil than mere activated carbon. In a batch study, maximum 96% indole removal was achieved with an initial indole concentration of 500 mg/L, catalyst dose of 10 g/L, time of 4 h, and reaction temperature of 303 K. The non-linear regression analysis was opted to fit the experimental equilibrium data into various adsorption isotherms, including Langmuir, Freundlich, Temkin and Redlich, and Peterson. Thermodynamic parameters of adsorption were investigated, and the entropy and heat of adsorption change were determined to be 0.26 kJ/mol K and 57.31 kJ/mol, respectively. Besides, a plausible adsorption mechanism of indole was also explored.

AbstractNano zero-valent iron particles (nZVI) supported on granular activated carbon (GAC) (nZVI/GAC) were synthesized and its feasibility was explored for the treatment of pyridine-bearing wastewater. nZVI/GAC was synthesized by the borohydride reduction method under ethanol atmosphere. The synthesized nZVI/GAC was characterized by scanning electron microscopy (SEM), X-ray diffraction, Fourier transform infrared spectroscopy, and N2adsorption–desorption study. Results indicated that the nZVI was well dispersed on the surface of GAC. The presence of support material apparently decreased the extent of aggregation and size of the nZVI and thus, facilitated in increasing the pyridine removal efficiency. Batch studies were carried out in order to evaluate the effect of operating parameters such as pH (2 ≤ pH ≤ 9), dose (m) (5 ≤ m ≤ 15 g/l), initial concentration (Co) (50 ≤ Co ≤ 1000 mg/l), and temperature (T) (288 ≤ T ≤ 318 K). At optimum condition, maximum removal of pyridine was found to be ~86% at m = 15 g/l, pH = 6, Co = 100 mg/l, and T = 303 K. The degradation kinetics has been investigated, and pseudo-first-order kinetic model was found to be suitable fit for the experimental data kinetic model. The apparent activation energy (Ea) of this process was found to be ~22.46 (kJ/mol). The nZVI/GAC showed stable performance for the degradation of pyridine-bearing wastewater until five consecutive cycles.

Nano zero-valent iron particles (nZVI) supported on granular activated carbon (GAC) (nZVI/GAC) were synthesized and its feasibility was explored for the treatment of pyridine-bearing wastewater. nZVI/GAC was synthesized by the borohydride reduction method under ethanol atmosphere. The synthesized nZVI/GAC was characterized by scanning electron microscopy (SEM), X-ray diffraction, Fourier transform infrared spectroscopy, and N2adsorption–desorption study. Results indicated that the nZVI was well dispersed on the surface of GAC. The presence of support material apparently decreased the extent of aggregation and size of the nZVI and thus, facilitated in increasing the pyridine removal efficiency. Batch studies were carried out in order to evaluate the effect of operating parameters such as pH (2 ≤ pH ≤ 9), dose (m) (5 ≤ m ≤ 15 g/l), initial concentration (Co) (50 ≤ Co≤ 1000 mg/l), and temperature (T) (288 ≤ T ≤ 318 K). At optimum condition, maximum removal of pyridine was found to be ~86% at m = 15 g/l, pH = 6, Co= 100 mg/l, and T = 303 K. The degradation kinetics has been investigated, and pseudo-first-order kinetic model was found to be suitable fit for the experimental data kinetic model. The apparent activation energy (Ea) of this process was found to be ~22.46 (kJ/mol). The nZVI/GAC showed stable performance for the degradation of pyridine-bearing wastewater until five consecutive cycles.

The present study investigated the viability of deep eutectic solvents (DESs) to extract dibenzothiophene (DBT) from model gasoline (iso-octane). Tetrabutylammonium bromide (TBAB)-based DES showed significant DBT extraction capability from the model fuel oil. Furthermore, the sigma profile confirmed that all TBAB-based DES had a significant capacity for DBT extraction from the model oil. The affinity order for the TBAB-based DES is as follows: TBAB/TEG (tri-ethylene glycol) > TBAB/PA (propionic acid) > TBAB/EG (ethylene glycol). To achieve maximum DBT extraction, the influencing parameters were adjusted, and 89% DBT extraction was achieved using the optimum conditions of oil to DES volume ratio of 1:1, with a DBT concentration of 500 ppm, residence time of 30 min, an extraction temperature of 303 K, and extraction stirring speed of 200 rpm.

Coal fly ash (CFA) has been employed as a catalytic support for lithium ions by impregnation. The basicity, basic strength, and stability of the resultant catalyst were further tuned by varying active species concentration (1 wt%–7 wt%) and calcination temperature (300–600 °C). The relationship between the basic properties of catalyst and their catalytic activity towards the conversion of glycerol (GL) was determined experimentally. It was found that 2 wt% lithium loaded CFA, calcined at 500 °C exhibited a maximum yield of glycerol carbonate (GC). The maximum catalytic activity was achieved at 90 °C with a reaction time of 2 h, 96.33% GL conversion, and 91.74% GC yield. Furthermore, ODE 15 s solver was used to evaluate reaction kinetics of the transesterification reaction. The activation energy was calculated and as 26.50 kJ/mol. The proposed work has the potential to uplift the economy of biodiesel industry.