Coconut Shell Activated Carbon Research Articles

Modelling and testing of VOC source suppression effect of building materials modified with adsorbents

Volatile organic compounds (VOCs) emitted from decorative building materials are the main source of indoor air pollution, which endangers human health. Source control is the most direct method to reduce the amount of harmful substances emitted from a material. In view of the excellent adsorption performance and effective fixation of the adsorbent on VOC molecules, small amounts of adsorbents can be blended into the raw materials used in the production of building materials, which results in the manufacture of modified building materials with low VOC emissions. According to the type and ratio of additional adsorbents, the VOC emission characteristics of the modified building materials vary. Based on the analysis of the multi-component and multi-scale mass transfer mechanism, a prediction system for the VOC emission characteristics of modified building materials was proposed. Four types of adsorbents, namely, wood-based activated carbon (WAC), shell activated carbon (SAC), coconut shell activated carbon (CSAC), and potassium permanganate impregnated alumina (PIA) were used to manufacture the modified medium density fiberboards. Moreover, pore structure characterization tests and environmental chamber tests were conducted to verify the accuracy of the theoretical prediction system. The results revealed that an absorbent with a high partition coefficient has a more significant source suppression effect. The proposed VOC emission characteristic prediction system for modified building materials can optimize the type and ratio of adsorbents for engineering applications and therefore, provide a basis for the selection of effective VOC source control strategies.

QSARs to predict adsorption affinity of organic micropollutants for activated carbon and β-cyclodextrin polymer adsorbents

The removal of organic micropollutants (MPs) from water by means of adsorption is determined by the physicochemical properties of the adsorbent and the MPs. It is challenging to predict the removal of MPs by specific adsorbents due to the extreme diversity in physicochemical properties among MPs of interest. In this research, we established Quantitative Structure–Activity Relationships (QSARs) between the physicochemical properties of a diverse set of MPs and their distribution coefficients (KD) measured on coconut shell activated carbon (CCAC) and porous β-cyclodextrin polymer (P-CDP) adsorbents. We conducted batch experiments with a mixture of 200 MPs and used the data to calculate KD values for each MP on each adsorbent under conditions of infinite dilution (i.e., low adsorbate concentrations). We used computational software to calculate 3656 molecular descriptors for each MP. We then developed and applied a model-selection workflow to identify the most significant molecular descriptors for each adsorbent. The functional stability and predictive power of the resulting QSARs were confirmed with internal cross validation and external validation. The applicability domain of the QSARs was defined based on the most significant molecular descriptors selected into each QSAR. The QSARs are predictive tools for evaluating adsorption-based water treatment processes and provide new insights into CCAC and P-CDP adsorption mechanisms.

Microwave irradiated coconut shell-activated carbon for decolourisation of palm oil mill effluent (POME)

Microwave irradiated coconut shell-activated carbon for decolourisation of palm oil mill effluent (POME)

Enhanced CO2 Adsorption on Activated Carbon‐Modified HKUST‐1 Composites

AbstractMesoporous activated carbon (AC)‐modified HKUST‐1 composites with different AC contents were prepared and were used for CO2 adsorption. The structure and physiochemical properties of the composites were characterized by scanning electron microscopy(SEM), X‐ray diffractometer(XRD), thermogravimetry(TG) and nitrogen adsorption techniques. The results showed that the surface area and micro pore volume for the HKUST‐1@AC composites increase obviously compared to the HKUST‐1. Especially, the HKUST‐1@AC/2% gave the maximum specific surface area of 1145.71 m2/g and micropore volume of 0.4363 mL/g, resulting in highest CO2 adsorption capacity of 155.7 mg/g, which is almost two times than that of the unmodified HKUST‐1. The content of oxygen‐containing functional groups in AC also play an important role in CO2 adsorption for the HKUST‐1@AC/2% composites, and the optimum content of oxygen‐containing functional groups for the coconut shell AC is about 2.9 mg/g. This might be due to that HKUST‐1 grows along the surface of AC with rich oxygen‐containing functional groups, and a large number of micropores are formed between the two interfaces, therefore increasing CO2 adsorption amount.

The Pertinence of Microwave Irradiated Coconut Shell Bio-Sorbent for Wastewater Decolourization: Structural Morphology and Adsorption Optimization Using the Response Surface Method (RSM).

Palm oil mill effluent contains carcinogenic coloured compounds that are difficult to separate due to their aromatic structure. Though colour treatment using adsorption processes at lower pH (<4) have been reported effectual, due to its acidity the remediated effluent poses an environmental hazard as a result. Thus, the current study focused on achieving decolourization at neutral pH by enhancing the morphology of the coconut shell activated carbon (CSAC) using N2 as activating-agent with microwave irradiation heating. The microwave pretreated and non-pretreated CSAC were characterized using scanned electron microscopy (SEM), energy dispersive X-ray (EDX) and Brunauer-Emmett-Teller (BET) analysis. A significant modification in the porous structure with a 66.62% increase in the specific surface area was achieved after the pretreatment. The adsorption experimental matrix was developed using the central composite design to investigate the colour adsorption performance under varied pH (6–7), dosage (2–6 g) and contact time (10–100 min). At optimum conditions of neutral pH (7), 3.208 g dosage and contact time of 35 min, the percentage of colour removal was 96.29% with negligible differences compared with the predicted value, 95.855%. The adsorption equilibrium capacity of 1430.1 ADMI × mL/g was attained at the initial colour concentration of 2025 ADMI at 27 °C. The experimental data fitted better with the Freundlich isotherm model with R2 0.9851.

Homogeneous solid dispersion (HSD) system for rapid and stable production of succinic acid from lignocellulosic hydrolysate.

Continuous bio-production of succinic acid was reported in homogeneous solid dispersion (HSD) system utilizing porous coconut shell activated carbon (CSAC) as immobilization carrier. The aim of the present work was to implement the HSD system to increase the area of cell immobilization and the rate of succinic-acid production from the lignocellulosic medium. The ratio of the two enzymes (cellulase-to-hemicellulase) was initially optimized to break down the lignocellulose into its free monomers, wherein the best ratio was determined as 4:1. Succinic-acid production was evaluated in the HSD system by varying the substrate loading and dilution rate. The results showed that high productivities of succinic acid were obtained when 60g/L glucose was fed over a dilution rates ranging from 0.03 to 0.4/h. The titer of succinic acid decreased gradually with higher dilution rate, whereas the residual substrate concentration increased with it. Critical dilution rate was determined to be 0.4/h at which the best productivity of succinic acid of 6.58g/Lh and its yield of 0.66g/g were achieved using oil palm fronds (OPF) hydrolysate. This work lends evidence to the use of CSAC and lignocellulosic hydrolysate to further exploit the potential economies of scale.

Adsorption equilibrium and thermodynamics of acetaldehyde/acetone on activated carbon

The adsorption characteristics of acetaldehyde/acetone onto coconut shell activated carbon (CSAC) were investigated with a dynamic apparatus. The Langmuir, Freundlich and Sips models were used to analyze the adsorption isotherm data in single gas system, revealing that the Freundlich model most suitably described the adsorption of the two gases. Henry’s law constant and the selectivity were investigated based on adsorption isotherms to understand adsorbent and adsorbate affinity. A thermodynamic study also revealed that the adsorptions were exothermic and phyiscal. The adsorption of these studied gases is likely to be heterogeneous. Acetone formed the more ordered configuration on CSAC, but molecular acetaldehyde has higher degree of freedom. For the binary adsorption system, the equilibrium data fit well with the Extended Freundlich model. The competitive adsorption experiment indicated that acetone was more selectively adsorbed than acetaldehyde on CSAC. In particular, because of the displacement of adsorbed acetaldehyde by acetone the acetaldehyde demonstrated a maximum excess concentration.

Preparation of CSC-PPy-TiO2 and application in photocatalytic for wastewater treatment

Polypyrrole modified TiO2 (PPy-TiO2) and coconut shell activated carbon (CSC) were used as raw materials, and Na2SiO3 was used to load PPy-TiO2 on the surface of coconut shell activated carbon. Finally the CSC-PPy-TiO2 photocatalyst was prepared. In this paper, the effects of the degradation effect of methyl orange on the factors such as the addition of PPy-TiO2 and the amount of sodium silicate were discussed. The experimental results showed that CSC-PPy-TiO2 had a good photocatalytic performance, and the decolorization rate of the methyl orange solution of 40mg / L was 88.52% in the light of metal halide lamp with 1.0g CSC-PPy-TiO2.

Adsorption of gold from cyanide leaching solution onto activated carbon originating from coconut shell—Optimization, kinetics and equilibrium studies

This study investigates the behavior of gold adsorption from cyanide leaching solution onto activated coconut shell carbon. The experimental was designed according to CCD implemented with RSM and a quadratic model was developed for regression analysis. The effects of important parameters including pH, agitation rate, adsorbent concentration and adsorption time were studied to find the best operating conditions, and the optimized value of pH, agitation rate, activated carbon concentration and adsorption time was found to be 11, 40 rpm, 1.25 g/L and 3 h, respectively. Under these conditions, the adsorption rate was found to be about 87.11%. Also, the optimal conditions were established on industrial cyanide leaching solution and the results demonstrated that adsorption rate of gold could be obtained about 89.25%. Adsorption behavior was kinetically investigated using pseudo first-order and pseudo second-order models among which data were mostly correlated to pseudo first-order model. The further analysis of kinetics indicated that intra-particle diffusion was the rate-limiting step. Adsorbate–adsorbent interactions at 298 k was assessed by Langmuir, Freundlich, and Temkin isotherm models from which Freundlich model had the highest consistency with the experimental data.

Benchmarking Micropollutant Removal by Activated Carbon and Porous β-Cyclodextrin Polymers under Environmentally Relevant Scenarios.

The cost-effective and energy-efficient removal of organic micropollutants (MPs) from water and wastewater is challenging. The objective of this research was to evaluate the performance of porous β-cyclodextrin polymers (P-CDP) as adsorbents of MPs in aquatic matrixes. Adsorption kinetics and MP removal were measured in batch and flow-through experiments for a mixture of 83 MPs at environmentally relevant concentrations (1 μg L-1) and across gradients of pH, ionic strength, and natural organic matter (NOM) concentrations. Performance was benchmarked against a coconut-shell activated carbon (CCAC). Data reveal pseudo-second-order rate constants for most MPs ranging between 1.5 and 40 g mg-1 min-1 for CCAC and 30 and 40000 g mg-1 min-1 for P-CDP. The extent of MP removal demonstrates slower but more uniform uptake on CCAC and faster but more selective uptake on P-CDP. Increasing ionic strength and the presence of NOM had a negative effect on the adsorption of MPs to CCAC but had almost no effect on adsorption of MPs to P-CDP. P-CDP performed particularly well for positively charged MPs and neutral or negatively charged MPs with McGowan volumes greater than 1.7 (cm3 mol-1)/100. These data highlight advantages of P-CDP adsorbents relevant to MP removal during water and wastewater treatment.

A novel bio-cellulose membrane and modified adsorption approach in CO2/H2 separation technique for PEM fuel cell applications

In this study, the membrane and the adsorption technologies approach are developed and used as a separation technique to separate carbon dioxide (CO2) and hydrogen (H2) gas mixture from biohydrogen dark fermentation. For a real application, the effect of CO2 impurity in the H2 fuel (i.e., the gas output from separation techniques) toward the PEM fuel cell performance was studied. Hence, a novel synthesized membrane made of glassy polymers, polyetherimide (PEI) coated bio-cellulose nanofibers and a coconut shell activated carbon (CAC) as adsorbents carriers were used. For the membrane separation technique, the bio-cellulose nanofiber is coated with PEI at varying concentration from 3 to 15 wt.%. The effect of PEI concentrations on the gas permeability and selectivity were observed. Meanwhile, for the adsorption separation technique, the performance of activated carbon was tested by using 0.6 L single column adsorber unit. The characterization of both developed membrane and adsorbent were analyzed including their morphologies and the physical properties. From the results, at 3 wt.% PEI coating, the CO2 permeability was 16.72 Barrer and corresponding selectivity of CO2/H2 was 0.15. Moreover, the adsorbents carriers showed a better adsorption capacity for CO2 removal at which 77.17 mg of CO2/g of adsorbent in a lower flow rate of feed gas at 0.5 L/min. In the case of PEM fuel cell, the performance would decrease with the increase of CO2 impurity in H2. Therefore, the results presented on this paper are the initial findings generated for the biohydrogen separation technology for the future portable power of PEM fuel cell application.

Potential use of coconut shell activated carbon as an immobilisation carrier for high conversion of succinic acid from oil palm frond hydrolysate

Coconut shell activated carbon (CSAC) presented excellent physicochemical characteristics for efficient conversion of oil palm frond (OPF) into succinic acid.

Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk Ash

Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk Ash

Competitive Adsorption of Methane and Carbon Dioxide on Different Activated Carbons

Adsorbed natural gas (ANG) is one of natural gas storage technologies, in which natural gas is adsorbed by a high porosity adsorbent material at relatively low pressure and room temperature with high methane capacity and low cost. Carbon-based materials, like activated carbons, are promising as an ANG storage adsorbent because of high surface area, high porosity, and high volumetric storage capacity. In this research, the adsorption capacity of single and binary component of CH4 and CO2 was investigated by using activated carbons including coconut shell activated carbon (CSAC), palm shell activated carbon (PSAC), and coal-based activated carbon (CBAC) in a packed bed column at room temperature. The composition ratio of single component of CH4 and CO2 was fixed at 20 vol% of the total feed gas, and the composition ratios of binary component of CH4 and CO2 were fixed at 14.6 : 5.4, 10.0 : 10.0, and 5.0 : 15.0 vol% of the total feed gases, respectively. The result of single component adsorption showed that all activated carbons exhibited preferential adsorption for CO2 in relation to CH4. It can be seen from binary component adsorption that the adsorbed amount increased with increased CO2 composition, while the amount of CH4 adsorbed decreased, indicating competition for adsorption sites and preferential adsorption of CO2 over CH4. In terms of the adsorption capacity of binary component, the methane selectivity was CSAC > PSAC > CBAC for the whole composition ratios of CH4 and CO2.

Simultaneous removal of phenol and cyanide from aqueous solution by co-culture of strain immobilized onto coconut shell activated carbon

In this study, the simultaneous biosorption and bioaccumulation of phenol and cyanide by co-culture/mixed culture of Pseudomonas putida (MTCC 1144) and Serratia odorifera (MTCC 5700) strains immobilized onto coconut shell activated carbon (CSAC) were investigated. The batch experiments were performed for the elimination of phenol and cyanide from mono and binary aqueous solution using initial concentrations of phenol (100–1,000 mg/L) and cyanide (10–100 mg/L). Under optimum conditions, the CSAC was demonstrated a biosorption capacity 500.55 mg/g of phenol and 2.41 mg/g of cyanide at pH 8, biomass dose 30 g/L and temperature 30°C. In a binary component system among six multicomponent isotherms, extended Freundlich model indicates a better fit for both phenol and cyanide. Moreover, the kinetic experimental results show that both phenol and cyanide were defined by the pseudo-first-order kinetic model. Thermodynamic study was established that the simultaneous biosorption and bioaccumulation of phenol indicates the exothermic nature of the process and cyanide indicates the endothermic nature of the process.

Activated carbons for the hydrothermal upgrading of crude duckweed bio-oil

This study examined a two-stage (noncatalytic pretreatment followed by catalytic upgrading) hydrothermal processing of crude bio-oil produced from the hydrothermal liquefaction of duckweed. The activities of six activated carbons (ACs)-pine wood AC, coconut shell AC, bamboo stem AC, apricot pit AC, peach pit AC, and coal AC-toward the deoxygenation and denitrogenation of the pretreated duckweed bio-oil were determined in supercritical water at 400°C for 1h with the addition of 6MPa of H2 and 10wt% AC. All of the ACs exhibited activity similar to Ru/C toward the denitrogenation and deoxygenation of the pretreated duckweed bio-oil. Of the ACs tested, bamboo stem AC produced an upgraded bio-oil with the highest yield (76.3wt%), the highest fraction (90.13%) of material boiling below 350°C, and the highest energy density (44.1MJ/kg). Decreased ash and acidic groups in the pre-treated AC disfavored the production of upgraded bio-oil but aided denitrogenation and desulfurization. The ACs are suspected to leach ions and weak acids into the reaction solution, which would catalyze denitrogenation and desulfurization. The gases mainly consisted of unreacted H2, CO2 and CH4 together with small amounts of CxHy (x≤5, y≤12) hydrocarbon gases produced from the cracking of the upgraded bio-oil.

Sustainable development of coconut shell activated carbon (CSAC) &amp; a magnetic coconut shell activated carbon (MCSAC) for phenol (2-nitrophenol) removal

Slow pyrolysis coconut shell (CSAC) and magnetic coconut shell (MCSAC) activated carbons were prepared, characterized and used for aqueous 2-nitrophenol (2-NP) removal.

A Statistical Approach to Optimization of Congo Red Dye Removal (CRDR) Via Coconut Shell Activated Carbon (CSAC)

The use of low-cost, locally available, highly efficient and eco-friendly adsorbents has been investigated as an ideal alternative to the current expensive methods of removing dyes from waste water. The aim of this work was the production of coconut shell activated carbon of Congo Red (CR) dye from aqueous solution. Batch adsorption studies were carried out by observing the effects of temperature and time, and the optimal experimental conditions were ascertained. Variables such as the adsorbent dose, initial concentration of solution and pH of solution were kept constant at 1 g, 100 mg/L and 7, respectively. The adsorptive capacity and percentage colour removal was mathematically described as a function of experimental parameters and was modelled through central composite response surface methodology (CCRSM). Results showed that the adsorption capacity and the percentage colour removal increased with an increase in time and temperature. The statistical predicted optimum values were validated by carrying out three experiments and an average Congo red (CR) of 86.82% and adsorption capacity (AC) of 8.50 mg/l were obtained at a time (X₁) = -1 and a temperature (X₂) = -1. The coefficient of determination (R²) and R-Sq. (adj.) for CR found in this study were 98.28% and 97.05%, while that for AC were 87.85% and 79.16%, respectively. Thus, the study concluded that the adsorbent was found to be effective, viable and suitable for the removal of Congo Red Dye from aqueous solution and its statistical analysis increased its optimum yields.

Direct dehydrogenation of isobutane to isobutene over carbon catalysts

Various carbon materials were found to function as highly active catalysts for the direct dehydrogenation of isobutane without the addition of oxidizing gases (such as oxygen, carbon dioxide or nitrous oxide) or the deposition of metal particles. Among these materials, coconut shell activated carbon (CSAC) generated the highest isobutane conversion of 70%. It is notable that the CSAC catalyst exhibited a high degree of catalytic stability that was comparable to that of conventional catalysts and was able to maintain a selectivity for isobutene of approximately 76%. The most important factor with regard to the catalytic activity of both fresh and used carbon catalysts was determined to be the specific surface area of the material. These results are unique since they indicate that various carbon materials, including deposited coke, can behave as effective catalysts for the isobutane conversion reaction even without the presence of functional groups.

Coconut Shell Activated Carbon Supported Quaternary Ammonium for Continuous Cycloaddition of CO2 and Biogas Upgrading in a Packed Bed

Quaternary ammonium was successfully prepared on coconut shell activated carbon (CSAC) granules. The samples were characterized by FT-IR, N2 adsorption–desorption, XPS, TG, and EA. The immobilized quaternary ammonium was thermally stable below 320 °C. The amount of immobilized quaternary ammonium on the CSAC was 0.957 mmol/g. Continuous cycloaddition of CO2 to epichlorohydrin (ECH) was carried out in a packed-bed reactor without using solvent or cocatalyst. When the reaction conditions were 130 °C and 1.4 MPa, the conversion of ECH and the corresponding turnover frequency (TOF) were 43.5% and 64.6 h–1, respectively. The selectivity to epichlorohydrin carbonate (ECHC) reached ∼100%. In biogas upgrading, grafting of quaternary ammonium was demonstrated to enhance CO2 capture capacity of the CSAC. The saturated CO2 capture capacities of the CSAC and the quaternary ammonium functionalized CSAC were 1.82 and 2.40 mmol/g at 20 °C and 0.5 MPa, respectively. The adsorption selectivities of CO2 over CH4 were ∼67% and 85% for the CSAC and the supported quaternary ammonium, respectively. The adsorption heat was 20–30 kJ/mol for the adsorbents. The supported quaternary ammonium also exhibited a relatively stable cyclability in a packed bed.