Microwave irradiated palm shell-polyetheretherketone porous carbons as CO2 sorbents: Optimization using response surface methodology (RSM)

Palm shell being one of the abundant biomass in Malaysia, was used together with polyetheretherketone (PEEK) as precursors for the preparation of porous carbons via microwave induced potassium carbonate chemical activation. Design expert software version 7.1.6 using central composite design coupled with surface response methodology was used in predicting and optimization of the CO2 adsorption of the porous carbons. Effect of three independent variables (i.e. microwave power, irradiation time and amount of PEEK) on the sorbent performance for CO2 adsorption was investigated. A quadratic model was developed to calculate the optimum preparation conditions of activated carbon, which relate the factors to the response (CO2 adsorption). The influence of process parameters on the properties of porous carbon was investigated using analysis of variance (ANOVA) to identify the significant parameters. Microwave power was found to be the most significant factor influencing the porous carbon for CO2 adsorption. The porous carbons (PCs) preparation conditions were optimized by maximizing the CO2 adsorption capacity. The predicted CO2 adsorption capacities from the models agreed satisfactorily with the experimental values. The optimum carbon was obtained at microwave power of 500 W; irradiation time 6.55 min; and amount of PEEK 26.03 %. Therefore, the Microwave-irradiated palm-PEEK was found to be a suitable adsorbent for uptake of CO2. Research paper: Microwave irradiated Palm shell-polyetheretherketone porous carbons as CO2 sorbents: Optimization using response surface methodology (RSM)

Natural gas adsorption on biomass derived activated carbons: A mini review

Activated carbon materials are good candidates for natural gas storage due excellent textural properties that are easy to enhance and modify. Natural gas is much cleaner fuel than coal and other petroleum derivatives. Storage of natural gas on porous sorbents at lower pressure is safer and cheaper compared to compressed and liquefied natural gas. This article reviews some works conducted on natural gas storage on biomass based activated carbon materials. Methane storage capacities and deliveries of the various sorbents were given. The effect of factors such as surface area, pore characteristic, heat of adsorption, packing density on the natural gas storage capacity on the activated carbons are discussed. Challenges, improvements and future directions of natural gas storage on porous carbonaceous materials are highlighted

Characteristics of oil palm shell biochar and activated carbon prepared at different carbonization times

Palm shells, which are agricultural by-products from palm oil processing, were used to produce low-cost activated carbons. Effect of different carbonization times (1–4 h) on the biochar and activated carbon properties was investigated. The carbonization was carried out at 700°C followed by CO2 activation. Carbons were characterized using Fourier transform infrared spectroscopy, ultimate analysis, scanning electron microscopy (SEM), proximate analysis and nitrogen adsorption. The proximate analysis of the palm shell showed low moisture content (5.5%), high percentage of volatile matter (70%), average contents of fixed carbon (23%) and ash content (4.28%). Carbonization times (1–4 h) within the range investigated have little influence on the char yield, thermal and chemical properties of the material but had more effect on the textural properties. SEM micrographs revealed that more pore networks and cavities were formed after carbonization and activation of the palm shells. The textural characteristics of the biochars and activated carbon reveal that the pore size is predominantly mesoporous. The properties of the palm shell activated carbon prepared at 700°C for 2 h indicated its ability to be used in volatile organics removal from wastewater and in gas-related adsorption applications

Assessment of Porous Carbons Derived from Sustainable Palm Solid Waste for Carbon Dioxide Capture

Potentials of solid agro-wastes from palm processing mills (palm kernel) for producing low cost porous carbons were investigated. The study deals with the use of palm kernel shell based porous carbons as adsorbents for CO2 capture. Carbonization of the palm kernel shell (PKS) was carried out at 700 °C followed by CO2 activation. The porous carbons were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric and derivative thermogravimetric (TG/DTA) analysis, scanning electron microscopy (SEM), proximate analysis, ultimate analysis and nitrogen adsorption tests. The adsorption equilibrium of CO2 on palm kernel shell activated carbon was measured using a static volumetric technique. Adsorption of CO2 on the porous carbons was conducted at 30 °C for pressures up to 4 bars. The equilibrium data were simulated using the Freundlich and Langmuir isotherms, with both models having R2 > 0.98. The experimental kinetic data was fitted to the pseudo-first-order, pseudo-second-order and Elovich equations, while the adsorption mechanism was evaluated using the Webber-Moris intra-particle diffusion model. Higher CO2 uptake of 7.32 mmol/g was obtained for PAC (palm kernel activated carbon) at 30 °C and 4 bars. PAC adsorbed 23.52 kg CO2/t PKS. The findings revealed the potential of palm shell as a viable and sustainable biomass for preparation of activated carbon for gas adsorption applications

Optimization of microwave irradiated - coconut shell activated carbon using response surface methodology for adsorption of benzene and toluene

Effluents from various industries release volatile organic compounds (VOCs) into the environment which causes serious environmental hazards. Coconut shell-based porous carbons were synthesized using chemical activation with potassium hydroxide (KOH) for adsorption of benzene and toluene. Central composite design of the response surface methodology was used in the optimization of the preparation conditions of the porous carbons. The effects of microwave power, irradiation time, and KOH impregnation ratio (IR) on benzene and toluene removal were investigated. The optimum condition was obtained at microwave power of 500 W; irradiation time 4 min; and 1.5 KOH IR, which resulted in 84 and 85% removal of benzene and toluene, respectively, at 95% yield of activated carbon (AC) from the char. Equilibrium data were fitted to Langmuir, Freundlich, and Temkin isotherms with all the models having R2 > 0.94. The equilibrium data were best fitted by Langmuir isotherm, with maximum adsorption capacity of 212 and 238 mg/g for benzene and toluene, respectively. High surface area of 1,354 m2/g and highly microporous carbon prepared lead to the high adsorption capacities. Pseudo-second-order kinetic model best fitted the kinetic data. The ACs produced can be used to remediate water polluted by VOCs

Pancreatic surgery outcomes: multicentre prospective snapshot study in 67 countries

Background: Pancreatic surgery remains associated with high morbidity rates. Although postoperative mortality appears to have improved with specialization, the outcomes reported in the literature reflect the activity of highly specialized centres. The aim of this study was to evaluate the outcomes following pancreatic surgery worldwide.Methods: This was an international, prospective, multicentre, cross-sectional snapshot study of consecutive patients undergoing pancreatic operations worldwide in a 3-month interval in 2021. The primary outcome was postoperative mortality within 90 days of surgery. Multivariable logistic regression was used to explore relationships with Human Development Index (HDI) and other parameters.Results: A total of 4223 patients from 67 countries were analysed. A complication of any severity was detected in 68.7 percent of patients (2901 of 4223). Major complication rates (Clavien-Dindo grade at least IIIa) were 24, 18, and 27 percent, and mortality rates were 10, 5, and 5 per cent in low-to-middle-, high-, and very high-HDI countries respectively. The 90-day postoperative mortality rate was 5.4 per cent (229 of 4223) overall, but was significantly higher in the low-to-middle-HDI group (adjusted OR 2.88, 95 per cent c.i. 1.80 to 4.48). The overall failure-to-rescue rate was 21 percent; however, it was 41 per cent in low-to-middle-compared with 19 per cent in very high-HDI countries.Conclusion: Excess mortality in low-to-middle-HDI countries could be attributable to failure to rescue of patients from severe complications. The authors call for a collaborative response from international and regional associations of pancreatic surgeons to address management related to death from postoperative complications to tackle the global disparities in the outcomes of pancreatic surgery (NCT04652271; ISRCTN95140761)