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Rambutan seeds (Nephelium lappaceumL.)-based activated carbon (RSAC) was prepared using potassium hydroxide (KOH) activation and carbon dioxide (CO2) gasification methods. The adsorbent prepared was characterized using Fourier transform infrared, SEM, proximate analysis, and BET techniques, respectively. The effects of three variable parameters; activation temperature, activation time, and chemical impregnation ratio (IR) (KOH: char by weight) on the preparation of RSAC used for the removal of MG dye was investigated. Based on the central composite design, quadratic and two factor interaction (2FI) models were, respectively, employed to correlate the effect of variable parameters on the preparation of RSAC used for the percentage MG dye removal and activated carbon yield. From the analysis of variance, the most influential factor on each experimental design response was identified. The optimum conditions of MG dye removal by RSAC are: activation temperature (802°C), activation time (1.0 h), and IR (2.4), respectively. The percentage MG dye removal obtained was 91.45% resulting in 22.56% RSAC yield. The percentage error between predicted and experimental results for the removal of MG dye is 2.4%. The effects of operational parameters like pH, initial dye concentration, contact time, and solution temperature were investigated using batch method. Graphical correlations of eight different adsorption isotherm models were carried out. Freundlich isotherm fitted the adsorption data most. The data were also analyzed by the Lagergren pseudo-first-order, Ho Mc Kay pseudo-second-order, Elovich and Avrami kinetic models. Pseudo-second-order kinetic model best represents the kinetic data and the mechanism of adsorption was controlled by both film and intraparticle diffusions. Thermodynamic studies gave negative ∆G° values, indicating that the process of MG dye adsorption onto RSAC was spontaneous. The positive values of ∆H° and ∆S° suggest that the process of dye adsorption was endothermic. [ABSTRACT FROM PUBLISHER]

The increasing global fuel consumption and growing environmental concerns are the impetuses to explore alternative energy that is clean and renewable for fuel production. Converting biomass and plastic waste into high-value fuel and chemicals via co-pyrolysis technique may provide a sustainable remediation to this problem. This review critically discussed the influence of various types of plastic wastes as co-reactant in co-pyrolysis with biomass on the product distribution, synergistic effect, and quality of bio-oil. The outcome of this review revealed that the addition of plastic enhanced the yield and quality of bio-oil and inhibited the production of oxygenated compound and coke formation. Next, the critical role of zeolite-based catalyst (microporous, mesoporous, hierarchical, and metal modified zeolite) and low-cost mineral-based catalyst in upgrading the yield and quality of liquid fuel were compared and discussed. The characteristic, synthesis method, strength, and limitation of each catalyst in upgrading the products were summarized. Hierarchical zeolites can resolve the problems of mass transfer, and diffusion limitation of large molecules into active sites associated with conventional zeolite due to the combination of two levels of porosity. Finally, the potential challenges and future directions for this technique were also suggested. [ABSTRACT FROM AUTHOR]

Activated carbon produced from pomelo peels (PPAC) was tested for its effectiveness in the removal of malachite green (MG) dye from aqueous solution. The PPAC prepared was characterized using TGA, BET, FTIR, SEM, pHpzc, Elemental analysis and Boehm titration, respectively. The extent of dye adsorption was investigated as a function of pH, contact time, adsorbate concentration and solution temperature. Dye removal was pH dependent, resulting in 95.06% removal at pH 8.0. Quantum chemical studies suggested that the cationic MG dye possessed minimal molecular size at planar geometry coupled with high-electrostatic interaction thereby, enhancing the adsorption at high pH. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) equilibrium isotherms were used to fit the adsorption data. Langmuir isotherm fit the adsorption data most with maximum monolayer adsorption capacity of 178.43 mg/g. The kinetic data fitted the pseudo-second-order model with correlation coefficient greater than 0.99. The mean free energyE(kJ/mol) got from the D–R isotherm indicated physisorption mechanism Thermodynamic parameters; Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) changes were also calculated, and the values indicated that the adsorption process was spontaneous and endothermic in nature. Regeneration efficiency of spent PPAC was studied using 0.2 M HCl, the efficiency was found to be in the range of 92.71–96.35% after four cycles. The study showed that PPAC can be used as an effective, low cost and environmentally friendly adsorbent for the removal of MG dye from aqueous solution. [ABSTRACT FROM PUBLISHER]

The adsorption of a group of heavy metals namely, Zn2+, Ni2+, and Cd2+onto olive stones activated carbon (OSAC) was carried out in this work. The effects of different reaction parameters, such as the adsorbent dosage, contact time, shaking speed, and initial pH, on pollutant removal efficiency were investigated. Adsorption of Zn2+, Ni2+, and Cd2+was effectively explained by Langmuir and Freundlich isotherms. OSAC efficiently removed 99.03% Zn2+, 97.34% Ni2+, and 94.88% Cd2+at pH 5 and shaking speed 200 rpm. Surface characteristics of the prepared AC were examined by pore structure analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The Brunauer-Emmett-Teller surface area, total pore volume and average pore diameter of the prepared AC were 886.72 m2/g, 0.507 cm/g, and 4.22 nm, respectively. The equilibrium data of the adsorption were fitted well to the Langmuir and the highest value of adsorption capacity (Q) on the OSAC was found for Zn2+11.14 mg/g, followed by Ni2+8.42 mg/g and Cd2+7.80 mg/g. A pseudo-second-order model sufficiently described the adsorption kinetics, which indicated that the adsorption process was controlled by chemisorption. The results revealed that the OSAC has the potential to be used as a low-cost adsorbent for the treatment of wastewaters contaminated with heavy metals. [ABSTRACT FROM PUBLISHER]

The adsorption of heavy metals Fe2+, Pb2+, and Cu2+onto olive stone activated carbon (OSAC) was investigated in this study. The effects of different reaction parameters (i.e. adsorbent dosage, contact time, shaking speed, and initial pH) on the pollutant removal efficiency were determined. The adsorption processes of Fe2+, Pb2+, and Cu2+were effectively explained using Langmuir and Freundlich isotherms. OSAC efficiently removed 99.39% Fe2+, 99.32% Pb2+, and 99.24% Cu2+at pH 5 and with 200 rpm shaking speed. The adsorption equilibrium data were best represented by the Langmuir model, and the monolayer adsorption capacities were found to be 57.47, 22.37, and 17.83 mg/g for Fe2+, Pb2+, and Cu2+, respectively. A pseudo-second-order model sufficiently described the adsorption kinetics, which indicated that the adsorption process was controlled by chemisorption. The results revealed that OSAC can be used as a low-cost adsorbent for the treatment of wastewaters contaminated by heavy metals. [ABSTRACT FROM PUBLISHER]

Activated carbon with high surface area was prepared from olive stone by microwave heating (MHOS) for the removal of a group of heavy metals Fe2+, Pb2+, and Cu2+ from synthetic wastewater. As a comparison, activated carbon was also prepared by conventional heating (CHOS) method. The effects of different reaction parameters, such as adsorbent dosage, contact time, stirring speed, and initial pH, on pollutant removal efficiency were determined. The microwave heating requires significantly lesser holding time as compared to conventional heating method to produce activated carbon of comparable quality, with higher yield. The BET surface area of carbon using microwave heating is noticeably higher than the conventional heating. Although the mesopore surface area of carbon is not vary significantly, the activation time and power consumption are considerably lower than the conventional heating rendering that the activation process via microwave is more economical than that via conventional heating. The adsorption capacity was found higher using microwave heating as compared with conventional heating. The adsorption equilibrium data were best represented by the Langmuir model and the adsorption capacity for Fe2+, Pb2+ and Cu2+ were found to be 62.50, 23.47, and 22.73 mg/g for MHOS; while 57.47, 22.37, and 17.83 mg/g for CHOS, respectively at pH 5, 3 h contact time and 200 rpm shaking speed. Regeneration studies showed that MHOS and CHOS could be used several times by desorption with an HCl reagent. A pseudo second-order model sufficiently described the adsorption kinetics for both carbons, which indicates that the adsorption process was controlled by chemisorption. Both carbons can be used for the efficient removal of Fe2+, Pb2+, and Cu2+ (>99%) from contaminated wastewater. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 1074-1085, 2014 [ABSTRACT FROM AUTHOR]

Health and environmental issues associated with heavy metal ions have received serious attention from communities worldwide. This work explores the potential of coconut shell as activated carbon (CSAC), in adsorbing zinc, Zn(II) ions. This adsorbent was prepared via a single-stage microwave irradiation technique under the flow of carbon dioxide, CO 2 gas. CSAC posed BET surface area of 625.61 m2/g, 513.25 m2/g of mesopores surface area, total pore volume of 0.42 cm3/g, and average pore diameter of 4.55 nm. Zeta potential distribution on CSAC was found to be −21 mV. Response surface methodology (RSM) had suggested that the optimum values of variables were 450 W and 3.17 min for radiation power and radiation time respectively, which resulted in 69.65% of Zn(II) removal and 44.32% of CSAC's yield. Based on F-value, radiation power (473.62) and radiation time (140.50) posed major and moderate effects on Zn(II) removal, respectively. Meanwhile, CSAC's removal was significantly affected by radiation power (78.84) and less affected by radiation time (7.06). In a batch study, when the initial concentration of Zn(II) was increased, Zn(II) uptakes increased as well. On contrary, Zn(II) removal percentage decreased with the increase of Zn(II)'s initial concentration. Multilayer adsorption of Zn(II) onto CSAC had occurred since this adsorption system followed Freundlich isotherm the best, and the monolayer adsorption capacity, Q m for Zn(II) was revealed to be 7.87 mg/g. The kinetic data of the Zn(II)-CSAC adsorption system was best described by pseudo-first-order (PFO) which indicated the role of physisorption. In the regeneration study, CSAC's mass and Zn(II) adsorption uptakes had reduced from 100% to 37% and 77%, respectively, after 6 regeneration cycles. [ABSTRACT FROM AUTHOR]

In attempt to compare the removal efficiency and yield of the activated carbon prepared using the conventional and microwave-assisted heating is the focus of this work. Toward this olive stone (a biomass precursor) is activated using the popular activating agent potassium hydroxide. The process optimization exercise is carried out by using the standard full factorial statistical design of experiments (response surface methodology). The activated carbons prepared under the optimized conditions are compared based on the adsorption capacity and yield. The adsorption capacity was found higher using microwave heating as compared with conventional heating. The microwave heating requires significantly lesser holding time as compared to conventional heating method to produce activated carbon of comparable quality, with higher yield. The BET surface area of carbon using microwave heating is significantly higher than the conventional heating. Although the mesopore surface area of carbon is not vary significantly, the activation time, power, and nitrogen gas consumption are significantly lower than the conventional heating rendering that the activation process via microwave is more economical than that via conventional heating. The adsorption isotherm data fitted the Langmuir isotherm well and the monolayer adsorption capacity was found to be 12.0 and 8.42 mg/g for microwave and thermally heated activated carbon, respectively. Regeneration studies showed that microwave-irradiated and thermally heated olive stone could be used several times by desorption with an HCl reagent. Both carbons can be used for the efficient removal of Ni2+ (>99%) from contaminated wastewater. © 2013 American Institute of Chemical Engineers AIChE J, 60: 237-250, 2014 [ABSTRACT FROM AUTHOR]

BACKGROUND The efficiencies of removal of Cu2+, Cd2+, Ni2+, Pb2+, Fe2+, and Zn2+ from aqueous solution with olive stone activated carbon ( OSAC) were investigated in this work. A central composite design ( CCD) method was used to optimize the preparation of OSAC using microwave assisted potassium hydroxide. RESULTS The optimum conditions obtained were 565 W radiation power, 7 min radiation time, and 1.87 impregnation ratio. This resulted in 98.55% removal of Cu2+, 95.32% of Cd2+, 98.19% of Ni2+ 98.83% of Pb2+, 99.32% of Fe2+, 98.36% of Zn2+, and 85.15% of OSAC yield. The surface characteristics of the AC prepared under optimized conditions were examined by pore structure analysis, scanning electron microscopy ( SEM) and Fourier transform infrared spectroscopy ( FT-IR). The BET surface area, total pore volume and average pore diameter of the prepared AC were 1280.71 m2 g−1, 0.604 cm3 g−1 and 4.63 nm, respectively. The equilibrium data of the adsorption was well fitted to the Langmuir equation and the highest value of adsorption capacity ( Q) on the OSAC was found for Fe2+ (62.50 mg g−1), followed by Pb2+ (23.47 mg g−1), Cu2+ (22.73 mg g−1), Zn2+ (15.08 mg g−1), Ni2+ (12.00 mg g−1), and Zn2+ (11.72 mg g−1). CONCLUSIONS OSAC prepared by microwaves can be used for the removal of metals from contaminated wastewater. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

A series of activated carbon from cocoa shell (CSAC) was prepared from cocoa shell pellet (CS) by carbonization and followed by physical activation using CO2 as the activation agent. Carbonization was done in a flow of N2 using a fixed-bed reactor at 400, 500, 600, 700, 800 and 900°C with soaking time at the carbonization temperature for an hour. The selected char indicated completion of the aromatization process which suggests no structural changes beyond this temperature. Char monolith, carbonized at 800°C were activated at 850°C using a fixed bed reactor for different burn-offs. The drilling of the pores possibly occurred at burn-off below 60% which indicated by huge increase of absolute pore volume against the burn-off. The surface area at 48.5% burn-off was estimated at 366.26m2 g−1. High burn-off product tends to develop larger micropore and moderate BET surface area. The largest surface area of CSAC was recorded at 558.25m2 g−1. During activation, the aromatization of CSAC increased but the aliphacity decreased accordingly. [ABSTRACT FROM AUTHOR]

In this work, the final concentration (Ce) of methylene blue (MB) dye adsorption by jengkol peel-based activated carbon (JPAC) in aqueous solution was simulated and validated using a dynamic model. JPAC was synthesized via physical process of microwave activation that consists the flow of N2 and CO2 gasification. The preparation conditions of JPAC at 400 Watt in 4 min of radiation power and activation time, respectively, achieved favorable properties for MB dye removal. JPAC has a BET surface area of 474.03 m2/g and pore volume of 0.3888 cm3/g. As the initial concentrations of MB dye increased from 25 to 300 mg/l, the adsorption capacity of MB on JPAC increased from 24.3 to 170.9 mg/g. It was found that calculated R2 values showed an agreement that the model fitted accurately experimental data with a correlation R2 more than 0.90 and the mass transfer coefficient decreases with increase in MB dye initial concentration. [ABSTRACT FROM AUTHOR]

ABSTRACT The adsorption of Remazol Brilliant Violet-5R (RBV-5R) reactive dye on cocoa pod husk activated carbon (CPHAC) was investigated in batch process. The effects of initial dye concentration, contact time, solution temperature and pH were evaluated. The equilibrium data were fitted into Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. It was found that Freundlich model fitted the adsorption data most. The kinetic data were fitted into pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. Adsorption of RBV-5R dye on CPHAC was best described by pseudo-second-order kinetic model. The adsorption of RBV-5R dye was favored at acidic pH. Thermodynamic parameters such as standard free energy Δ G0, standard enthalpy Δ H0 and standard entropy Δ S0 were calculated. The adsorption interaction of RBV-5R reactive dye on the adsorbent was found to be feasible, spontaneous and endothermic. The adsorption process followed a physisorption mechanism. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper reported the experimental result of breakdown voltage characteristics of Refined, Bleach and Deodorized Palm Olein (RBDP Olein) with 10-50% of Envirotemp FR3mixture. The experiment was conducted at temperature of 40°C to 100°C under quasi-uniform electric field of AC applied voltage. In addition, the dissipation factor, water content, and the chemical compositions of the oil mixture were also investigated. Experimental result for RBDP Olein/FR3 mixtures revealed the increase trend of breakdown voltage with the increasing of FR3 ratio. All the breakdown voltage of RBDP Olein/FR3 mixtures are fulfill the IEC 156 standard which is greater than 30kV. The result of dissipation factor shows the increment trend for the RBDP Olein with ascending ratio of FR3 mixture. Analysis of chemical composition of RBDP Olein/FR3 mixtures shows the decrease of palmitic acid and significant increment of linoleic acid and linoleic acid. Gas Chromatography result also reveals the presence of BHT which is antioxidant additives in FR3 liquid. The water content in RBDP Olein/FR3 mixtures shows the decrease trend with the increase of FR3 ratio that yield to higher breakdown voltage of the oil mixture. The antioxidant presence in FR3 might be affecting the result of water content in this experiment. [ABSTRACT FROM AUTHOR]

The treatability of semi-aerobic landfill leachate parameters using durian peel-based activated carbon (DPAC) was investigated. An ideal experimental design was conducted based on central composite design (CCD) using response surface methodology to evaluate individual and interactive effects of operational variables namely activation temperature, activation time and carbon dioxide (CO2) flow rate on treatment performance in terms of chemical oxygen demand (COD) and colour removal efficiencies. The DPAC was prepared using physical activation method which consists of CO2 gasification. The adsorptions of COD and colour were described by Langmuir and Freundlich isotherm models. Based on the CCD, quadratic model was developed to correlate preparation variables to the two responses. The optimum DPAC preparation conditions were obtained using 800 °C activation temperature, 2.1 h activation time and 68.68 ml/s of CO2 flow rate. From the experimental work, the maximum removal of COD and colour obtained were 41.98 and 39.86%, respectively. [ABSTRACT FROM AUTHOR]

Co-pyrolysis of palm wastes of empty fruit bunch (EFB) and palm frond (PF) with low-density polyethylene (LDPE) and polypropylene (PP) were investigated to find the synergistic effect of biomass-plastic pair on the yield and composition of bio-oil produced. The pyrolysis process of individual materials and their corresponding blends were employed in a fixed bed reactor at heating rate of 20 °C/min with a nitrogen flow rate of 250 mL/min. The co-pyrolysis results showed that EFB:LDPE with weight ratio of 1:1 has the largest synergy on bio-oil yield, while a negative synergy was revealed for PF:PP co-pyrolysis. In regard of bio-oil chemical composition, the synergistic effect was positive for the formation of aliphatic hydrocarbons and all feedstock decreased the overall oxygenated compounds of fuel substitute. The hydrogen generated from plastic promoted the decarboxylation of acids and decarbonylation reactions of carbonyls and sugars. [ABSTRACT FROM AUTHOR]

This study assesses the performance of optimized acacia wood-based activated carbon (AWAC) as an adsorbent for methylene blue (MB) dye removal in aqueous solution. AWAC was prepared via a physicochemical activation process that consists of potassium hydroxide (KOH) treatment, followed by carbon dioxide (CO 2) gasification under microwave heating. By using response surface methodology (RSM), the optimum preparation conditions of radiation power, radiation time, and KOH-impregnation ratio (IR) were determined to be 360 W, 4.50 min, and 0.90 g/g respectively, which resulted in 81.20 mg/g of MB dye removal and 27.96% of AWAC's yield. Radiation power and IR had a major effect on MB dye removal while radiation power and radiation time caused the greatest impact on AWAC's yield. BET surface area, mesopore surface area, and pore volume of optimized AWAC were found to be 1045.56 m2/g, 689.77 m2/g, and 0.54 cm3/g, respectively. Adsorption of MB onto AWAC followed Langmuir and pseudo-second order for isotherm and kinetic studies respectively, with a Langmuir monolayer adsorption capacity of 338.29 mg/g. Mechanism studies revealed that the adsorption process was controlled by film diffusion mechanism and indicated to be thermodynamically exothermic in nature. [ABSTRACT FROM AUTHOR]

One of the challenges in biomass gasification industry is the solid waste disposal mostly in the form of char. This article aims to prepare the gasified Hevea brasiliensis root based activated carbon (GHBRAC) for the sequestration of malachite green (MG) dye, to analyse the GHBRAC characteristics that are responsible for adsorption and to evaluate the MG uptake capacities of the prepared GHBRAC. The gasified Hevea brasiliensis root (GHBR) was obtained from commercial gasification plant and physiochemically treated with potassium hydroxide (impregnation ratios = 2.00) and carbon dioxide (flowrate = 150 cm3/min) via microwave irradiation (radiation power = 616 W). The total pore volume (TPV) and BET surface area (S BET) of GHBRAC were 0.273 cm3 and 477.74 m2/g respectively. The isothermal data best fitted to the n-BET model while the kinetic data followed the Avrami model equation, revealing a multilayer adsorption. The thermodynamic data of MG adsorption by GHBRAC showed that the process was spontaneous and endothermic. The Yoon–Nelson, Thomas and Yan models effectively predicted the adsorption of MG in fixed-bed column. GHBRAC was found to be economically feasible for commercialization owing to its low production cost and high adsorption capacity. [ABSTRACT FROM AUTHOR]

Emerging contaminants (EC) like chloramphenicol in wastewater are highly related to human, livestock, and aquaculture therapeutic activities. High levels of chloramphenicol in water may cause toxic effects on an aquatic environment, humans, and animals. The removal of chloramphenicol in wastewater was the main objective of this study. This study explores the use of microwave irradiation in the production of Rambutan peel-based activated carbon (RPAC) at a heating power of 700 W for 15 min under carbon dioxide, CO 2 gas flow. RPAC had a BET surface area of 583.44 m2/g, mesopores surface area of 469.87 m2/g, total pore volume of 0.27 cm3/g, and average pore diameter of 2.31 nm. The equilibrium study shows that the concentration of Cp adsorbed by RPAC increased as the initial concentration increased from 4.93 mg/g to 25.10 mg/g. Isotherm adsorption determined that Langmuir was the preferred model since it has the lowest RSME and highest R2 of 3.34 and 0.9994, respectively. It was observed from kinetic studies that the adsorption system relies on the pseudo-second order. According to thermodynamic studies, the enthalpy change, △H° and Gibbs free energy, △G° obtained indicating that the adsorption process occurs in an exothermic and spontaneous state. • Microwave heating created RPAC with BET and mesopores surface area of 583.44 m2/g and 469.87 m2/g, respectively. • Cp-RPAC adsorption system was best described by Langmuir isotherm and PSO kinetic model. • The maximum Langmuir adsorption capacity, Q m for Cp was 33.08 mg/g. • Boyd plot revealed that the rate limiting step was film diffusion. • The adsorption of Cp onto RPAC was exothermic and spontaneous in nature. [ABSTRACT FROM AUTHOR]

This study addresses concerns about amoxicillin (AMOX) in wastewater by enhancing its removal using Cu salt-modified lemon peel-based activated carbon (Cu-LPAC). The F-test is employed to assess variances between linear and non-linear methods for isotherm and kinetic models. The Polymath mass transfer (PMT) model is used to simulate kinetic data. AMOX adsorption onto Cu-LPAC increased by 38.93%, in comparison with pristine LPAC. The Cu-LPAC exhibiting BET surface area, pore volume, and pore diameter of 1018.52 m2/g, 0.5377 cm3/g, and 2.78 nm. The non-linear Langmuir and non-linear pseudo-second order (PSO) models fit the adsorption process. The Langmuir monolayer adsorption capacity (Q m) was 344.84 mg/g (linear) and 355.67 mg/g (non-linear). The F-test showed significance differences for Freundlich and PSO, while PMT model simulation accurately predicted the mesopores surface area to be 787.63 m2/g, yielding a small error of 4.31%. Cu-LPAC's AMOX adsorption was enhanced by ion dipole, hydrogen, and dipole-dipole bonds. [Display omitted] • The Cu-LPAC boosted AMOX adsorption by 38.93% compared to pristine LPAC. • The PMT predicted 787.63 m2/g of surface area, close to the actual value of 823.12 m2/g. • The Q m for Cu-LPAC was 344.84 mg/g (linear method) and 355.67 mg/g (non-linear method). • F-test revealed that the null hypothesis was accepted for Langmuir, Temkin and PFO. • AMOX adsorption onto Cu-LPAC was enhanced by the ion-dipole bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • The RBBR uptakes by optimized JPAC were 196.05 mg/g, with a yield of 33.18 %. • Langmuir adsorption capacity, Q m of JPAC in adsorbing RBBR was 260.46 mg/g. • RBBR was attracted to JPAC's surface via hydrogen bonds and ion–dipole forces. • The PMT model precisely predicted JPAC's surface area as 739.96 m2/g (4.76 % error). • Adsorption system was spontaneous, endothermic, and followed Freundlich model. Adverse effects caused by synthetic dyes can persist in the environment for a long time because they are highly soluble in water and have a stable structure. Hence, the objectives of this study were: (i) to optimize the preparation of jackfruit peel based activated carbon (JPAC) to adsorb remazol brilliant blue R (RBBR) dye and (ii) to simulate the adsorption process using Polymath mass transfer (PMT) model. The JPAC was produced through a physicochemical activation process combining potassium hydroxide, KOH, and carbon dioxide, CO 2 treatments. The response surface methodology (RSM) revealed the optimum preparation conditions to be 737 °C, 1.00 h, and 1.92 g/g for activation temperature, activation time, and impregnation ratio (IR), respectively, which corresponded to 196.05 mg/g of RBBR uptakes and 33.18 % of JPAC's yield responses. The equilibrium study disclosed that the adsorption capacity of JPAC in removing RBBR increased when RBBR starting concentration increased and the adsorption process was favoured at 50 °C (220.56 mg/g) and solution pH of 4 (85.67 mg/g). Isotherm study found the adsorption process to follow the Freundlich model whilst the Langmuir monolayer adsorption capacity, Q m was computed to be 260.46 mg/g. In terms of kinetic, the adsorption process was best described by the PMT model with mass transfer coefficient, k m between 0.00069 and 0.00080 mg⋅m/L⋅s and surface area, a PMT estimation of 739.96 m2/g. This value is highly precise in comparison with the actual mesopores surface area of 706.35 m2/g (error = 4.76 %). The functional groups on JPAC's surface were found to interact with RBBR molecules through hydrogen bonds, dipole–dipole bond and ion–dipole bonds. The thermodynamic study confirmed the adsorption process to be endothermic (ΔH° = 32.36 kJ/mol), increased randomness at the solid–liquid interface (ΔS° = 0.19 kJ/mol.K), spontaneous (ΔG° = −24.69 kJ/mol) and controlled by physisorption (E a = 29.40 kJ/mol). Besides determining the mass transfer coefficient, this study is novel in terms of applying the PMT model to predict the surface area. Predicting the surface area provides a quick assessment of the adsorption performance of the activated carbon, thus saving time and cost compared to conducting the actual surface area characterization test. [ABSTRACT FROM AUTHOR]

The increasing presence of chloramphenicol (CAP) in aquatic environments each year has led to serious concerns regarding potential adverse effects on human health, the environment, and aquatic organisms. If CAP residues are not sufficiently removed during wastewater treatment, they can migrate into the aquatic environment and eventually end up in the food chain. Therefore, the removal of CAP from river bodies is of great importance. In this research study, a novel sodium bicarbonate (NaHCO3)-impregnated coconut husk-activated carbon (CHAC) was developed through an impregnation method for CAP removal. The introduction of NaHCO3 on the CHAC surfaces results in the formation of OH– and H2O functional groups. The presence of a hydroxyl group appears mainly due to the water molecules found in the middle layer of the adsorbent and might be due to the water molecules that are physically adsorbed. This suggests that OH– groups found on the outer layer of the NaHCO3-impregnated CHAC are the main contributors to the removal of CAP through chemical interaction and electrostatic attraction. Based on the response surface methodology approach, the best preparation conditions for activation temperature, activation time, and IR were identified to be 500 ℃, 1 h, and 0.5, respectively. The optimized CHAC was found to be homogeneous and had a mesoporous type of pores with a BET surface area of 438.2 m2/g. In the batch adsorption study, the uptake of CAP onto CHAC increased as both the initial concentration of CAP and contact time increased. In terms of the effect of solution pH, CAP removal was highest at pH 2 and lowest at pH 13. The Langmuir isotherm and pseudo-first-order (PFO) kinetic were the best-fitted models for CAP adsorption. Besides, the adsorption process was mainly governed by the film diffusion mechanism. Based on the thermodynamic study, CAP adsorption onto CHAC was found to be exothermic in nature and spontaneous. [ABSTRACT FROM AUTHOR]

Pyrolysis studies often overlook the potential of pyrolytic gas as a valuable hydrocarbon resource, thereby hindering the production of advanced carbonaceous nanomaterials (CNM). This study aims to explore various configurations of a multi-zone tubular reactor to upcycle disposable face masks into non-condensable hydrocarbons as potential CNM precursors. The highest gas yield (56.2 wt%) was achieved using a 3-zone configuration (Z-1,3,4), attributed to the end chain scission mechanism. The increased abundance of light hydrocarbons (≤C10) in the resulting liquid confirms a greater extent of end chain scission in the optimum reactor configuration with cold zone retainment. Employing this configuration, different face mask types, including 3ply (polypropylene-based), KF94 (polypropylene-based) and N95 (polyester-based), were utilized as individual feedstocks or in various ratios as mixtures to investigate the resultant composition of hydrocarbon gases. This composition was compared with existing literature studies to identify suitable hydrocarbon gas compositions for CNM production. Mixing 3ply and KF94 face masks produced a consistent gas composition predominantly comprising propylene (62.3 – 66.9%) and ethane (15.4 – 16.8%) via thermal pyrolysis at 500 ℃ with a constant heating rate of 20 ℃/min. However, the inclusion of N95 face masks increased CO 2 level fivefold, diminishing the gas quality as a CNM precursor. These findings underscore the necessity of segregating polyester face mask material from polypropylene face mask material prior to pyrolysis to ensure a consistent quality and yield of CNM precursors. [Display omitted] • Disposable face masks were pyrolyzed to produce non-condensable hydrocarbons. • A vertical tubular reactor was configured to maximize the yield of hydrocarbon gas. • Face mask types can be mixed to produce consistent hydrocarbon gas composition. • Feasibility of upgrading the hydrocarbon gas into carbon nanomaterial was discussed. [ABSTRACT FROM AUTHOR]

Improper management of organic industrial wastes, such as empty fruit bunch (EFB) from the palm oil industry and pressmud, i.e., a by-product of the sugar refinery industry can lead to environmental problems. This study aims to investigate the potential of pressmud and EFB as adsorbent materials in wastewater pollution removal. The chemical analysis in this study revealed that the EFB sample contained 7.30% of SiO2, 2.11% of Fe2O3, 1.91% of MgO, 28.02% of CaO, 37.59% of K2O, 1.45% of P2O5, 14.51% of Cl, 4.39% of SO3, and 2.38% of other elements. Meanwhile, the pressmud sample contained 14.32% of SiO2, 1.39% of SO3, 81.71% of CaO, 1.03% of Fe2O3, and the remaining 1.56% of other compounds. The possible adsorption capacities of pressmud and EFB were determined using the Langmuir and Freundlich isotherms. The absorption of Cd, Cr, Cu, Fe, Mn, Ni, and Zn in these samples was analyzed using the Langmuir and Freundlich isotherm models. By comparing both models, the research revealed that the Langmuir model provided a more precise description of the adsorption process for the EFB and pressmud samples and was competently compared to the Freundlich model, as indicated by the highest R2 values. The results indicate the potential of EFB and pressmud as promising reactive materials for heavy metal adsorption, and this involves recognizing possibilities for repurposing these economical and sustainable waste materials. [ABSTRACT FROM AUTHOR]

The exposure of basic dye towards human and environment can caused severe adverse effects. Hence, this study aimed (i) to optimize the adsorption of malachite green (MG) dye onto jackfruit peel based activated carbon (JPAC) by using response surface methodology (RSM) and (ii) to simulate the mass transfer process using Polymath mass transfer (PMT) model. The RSM revealed that the optimum activation temperature, activation time and potassium hydroxide (KOH) impregnation ratio, IR to be 782 °C, 1 h and 2.96 g/g which translated into 66.80 mg/g of MG adsorption and 34.52 % of JPAC's yield. The Freundlich isotherm model described the adsorption process the best while the Langmuir monolayer adsorption capacity was computed to be 376.33 mg/g. The kinetic data obeyed the PMT model the best where the rate constant, K PMT decreased from 1.20 to 0.41 h−1 as the MG concentration increased from 25 to 300 mg/L. Also, the PMT model was succeeded in predicting the surface area, a PMT of JPAC to be 807.77 m2/g and this value is comparable with the actual JPAC's mesopores surface area of 714.25 m2/g (error 11.58 %). The adsorption of MG onto JPAC was aided by several functional groups such as primary or secondary alcohol, non-bonded hydroxy group and methoxy through ion-dipole force and dipole-dipole force. Based on thermodynamic parameters, MG-JPAC adsorption system was endothermic in nature (∆H° = 37.12 kJ/mol), had an increment of randomness at solid-liquid interface (∆S° = 0.19 kJ/mol·K), spontaneous in nature (−20.11 kJ/mol) and physisorptionally governed (E a = 9.46 kJ/mol). [Display omitted] • Preparation of JPAC were optimized by using response surface methodology. • The maximum adsorption capacity of JPAC in adsorbing MG dye was 376.33 mg/g. • Adsorption followed Freundlich isotherm and polymath mass transfer (PMT) model. • PMT predicted surface area to be 807.77 m2/g (actual surface area was 714.25 m2/g). • MG-JPAC adsorption system was aided by ion-dipole force and dipole-dipole force. [ABSTRACT FROM AUTHOR]

A report on the de novo Whole Genome Sequence (WGS) of Marinobacter litoralis SW-45, a moderately salt-tolerant bacterium isolated from the seawater in Malaysia is presented. The strain has a genome size of 3.45 Mb and is capable of producing halophilic lipase, protease and esterase enzymes. Computational prediction of non-coding RNA (ncRNA) genes in M. litoralis SW-45 was performed using standalone software known as the non-coding RNA characterization (nocoRNAc). In addition, a phylogenetic tree showing the evolutionary relationship between the strain and other members of the genus Marinobacter was constructed using 16SrRNA sequence information. A total of 385 ncRNA transcripts, 1124 terminator region, and 2350 Stress Induced Duplex Destabilization sites were predicted. The current WGS shotgun project has provided the relevant genetic information that may be useful for the strain's improvement studies. This manuscript gives the first description of M. litoralis with a complete genome. [ABSTRACT FROM AUTHOR]

This study is aimed to improving extracellular lipase production by Trichoderma strains using oil palm empty fruit bunch (OPEFB) medium on solid state fermentation with the assistance of statistical optimization. Two selected Trichoderma strains ( Trichoderma sp.1 and Hypocrea neorufa.1 ) with high lipase producing potential were employed in a stepwise optimization. Initially, the influence of nutritional (carbon, nitrogen sources, and inducers) and environmental (moisture and temperature) factors on lipase production was evaluated using One-Factor-At-A-time (OFAT) method. Next, three most influential factors (Glucose, Urea and Olive oil) resulting from OFAT were optimized for lipase production by Trichoderma sp.1 using the central composite design under response surface methodology. Experiments conducted under optimum conditions (10.38% (w/w) glucose, 0.86% (w/w) urea, and 7.38% (v/w) olive oil) were further improved the lipase production from 0.195 to 0.390 Ug −1 , which is about 2 folds greater than un-optimized condition. This study demonstrated that OPEFB can be utilized as inexpensive substrate for improving the lipase secretion by Trichoderma sp.1. [ABSTRACT FROM AUTHOR]

In this work, engineered biochar decorated layered double hydroxides and cellulose nanocrystals (B–CuFe–CNC) biocomposites were synthesized by the facile ultrasonicated-co-precipitation technique. The biocomposite was investigated for purification of Eriochrome Black T (EBT) dye from water. The characterization results showed that the presence of CNC in biochar-layered double hydroxides resulted in a two-dimensional rod-like structure with excellent crystallinity, improved surface functionalities, and provides an attractive platform for the enhanced adsorption of azo anionic dye molecules. The adsorption system was appropriately demonstrated by the BBD-RSM (R2 > 0.994). The biocomposite exhibited higher EBT adsorption in the acidic pH range (2–5) due to strong electrostatic and chemical interactions. The kinetic and isotherm results were well demonstrated by pseudo-second order, Freundlich, and Redlich Peterson models. The maximum adsorption capacity of biocomposite was 876.2 mg/g achieved within 45 min. The spectroscopic analyses imply that the high removal of EBT by biocomposite is mainly governed by electrostatic attraction, hydrogen bonding, and chemical/metal complexation mechanisms. The biocomposite maintained high EBT removal after six successive adsorption cycles and excellent dye adsorption in the different water matrices. The results suggest that tailoring biochar properties with layered double hydroxide and CNC is a promising way for the enhanced removal of dye contaminants from wastewater. [Display omitted] • Biochar-CuFe-CNC biocomposites were fabricated by simple co-precipitation method. • The biocomposite exhibited superior adsorption of Eriochrome Black T(EBT) dye. • The adsorption capacity of B-CuFe-CNC was five and three folds higher than biochar and CuFe LDH. • The presence of CNC improved the surface functionality and hydrophilicity. [ABSTRACT FROM AUTHOR]

In this research work, a novel hybrid composite consisting of biochar (B), layered double hydroxide (CuFe) and chitosan (CS) (B-CuFe-CS) was produced using an ultrasonication-assisted co-precipitation method. The resultant composite was employed for adsorptive removal of Eriochrome black T (EBT) from water. Physicochemical characterization indicated that the B-CuFe-CS containing 10 wt % CS exhibited a heterogeneous structure with better crystallographic and textural characteristics. The B-CuFe-CS with abundant surface functionalities (-C O, -C-O, –OH, –NO 3, and MMO), facilitates faster and enhanced removal of the EBT. The kinetic results showed better fitting to the pseudo-second order model, and equilibrium was achieved within 30 min. Equilibrium data was well explained by Langmuir and Redlich Peterson isotherm models (R2 > 0.98), indicating the EBT removal onto B-CuFe-CS followed monolayer adsorption. The maximum adsorption capacity was 806.4 mg/g, which was higher than pristine B–CuFe (476.19 mg/g) and many other adsorbents. The spectroscopic analysis (FTIR and XPS) and experimental results suggested that EBT adsorption is mainly governed by electrostatic, chemical and anion-exchange interactions. It is evident from these results that coupling B–CuFe composite with bio-filler (chitosan) resulted in an efficient bio-adsorbent to effectively purify dye-contaminated water streams. • Sustainable B-CuFe-CS biocomposite was fabricated. • B-CuFe-CS composite shows superior adsorption performance towards Eriochrome Black T (EBT). • Incorporated CS improved the surface functionality of the composite that resulted in enhanced EBT adsorption. • B-CuFe-CS EBT adsorption capacity (806.4 mg/g) was 1.5 times higher than B–CuFe (476.19 mg/g). [ABSTRACT FROM AUTHOR]

This study aimed to assess the dynamic simulation models provided by Aspen adsorption (ASPAD) and artificial neural network (ANN) in understanding the adsorption behavior of atenolol (ATN) on gasified Glyricidia sepium woodchips activated carbon (GGSWAC) within fixed bed columns for wastewater treatment. The findings demonstrated that increasing the bed height from 1 to 3 cm extended breakthrough and exhaustion times while enhancing adsorption capacity. Conversely, higher initial ATN concentrations resulted in shorter breakthrough and exhaustion times but increased adsorption capacity. Elevated influent flow rates reduced breakthrough and exhaustion times while maintaining constant adsorption capacity. The ASPAD software demonstrated competence in accurately modeling the crucial exhaustion points. However, there is room for enhancement in forecasting breakthrough times, as it exhibited deviations ranging from 6.52 to 239.53% when compared to the actual experimental data. ANN models in both MATLAB and Python demonstrated precise predictive abilities, with the Python model (R 2 = 0.985) outperforming the MATLAB model (R 2 = 0.9691). The Python ANN also exhibited superior fitting performance with lower MSE and MAE. The most influential factor was the initial ATN concentration (28.96%), followed by bed height (26.39%), influent flow rate (22.43%), and total effluent time (22.22%). The findings of this study offer an extensive comprehension of breakthrough patterns and enable accurate forecasts of column performance., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The presence of emerging contaminants (ECs) originating from pharmaceutical waste in water, wastewater, and marine ecosystems at various geographical locations has been clearly publicised. This review paper presents an overview of current monitoring data on the occurrences and distributions of ECs in coastal ecosystem, tap water, surface water, ground water, treated sewage effluents, and other sources. Technological advancements for EC removal are also presented, which include physical, chemical, biological, and hybrid treatments. Adsorption remains the most effective method to remove ECs from water bodies. Various types of adsorbents, such as activated carbons, biochars, nanoadsorbents (carbon nanotubes and graphene), ordered mesoporous carbons, molecular imprinting polymers, clays, zeolites, and metal-organic frameworks have been extensively used for removing ECs from water sources and wastewater. Extensive findings on adsorptive performances, process efficiency, reusability properties, and other related information are thoroughly discussed in this mini review., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The adsorption behavior of basic, methylene blue (MB), and reactive, remazol brilliant violet 5R (RBV), dyes from aqueous solution onto Intsia bijuga sawdust-based activated carbon (IBSAC) was executed via batch and column studies. The produced activated carbon was characterized through Brunauer-Emmett-Teller (BET) surface area and pore structural analysis, proximate and ultimate, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Batch studies were performed to investigate the effects of contact time, initial concentration, and solution pH. The equilibrium data for both MB and RBV adsorption better fits Langmuir model with maximum adsorption capacity of 434.78 and 212.77 mg/g, respectively. Kinetic studies for both MB and RBV dyes showed that the adsorption process followed a pseudo-second-order and intraparticle diffusion kinetic models. For column mode, the breakthrough curves were plotted by varying the flow rate, bed height, and initial concentration and the breakthrough data were best correlated with the Yoon-Nelson model compared to Thomas and Adams-Bohart model. The adsorption activity of IBSAC shows good stability even after four consecutive cycles.