Preparation of shape-stabilized phase change material nanocomposite using palm kernel shell activated carbon for thermal energy storage

Nanomaterials study is an emerging field of research that received considerable attention due to their potential impact on every domain of science and technology. Their benefits to the various fields of study in research and application such as waste water treatment, biomedical, electronics and energy storage makes nanomaterials broad and interdisciplinary in research and development. The constant growth of increase in waste materials and need for energy caused serious international concern towards the biodiversity. This issue can be matched with thermal energy storage (TES) which is the temporary storage of high or low temperature energy from direct solar energy. TES in buildings has recently attracted much attention. The applications of phase change material (PCM) as the medium for energy storage in the buildings were designated as to reduce and maintained the comfort temperature. Activated carbon as the framework materials for PCM have the potential to protect the PCM from the external environment, increase the heat transfer area, control the volume changes and increase the thermal conductivity during the application. The aim of this study is to prepare shape-stabilized phase change material (SSPCM) for TES application in the building. Palm kernel shell (PKS) was used as the precursor and treated with H3PO4 at different concentration and activated at different temperatures in different holding time for the optimization as to see the effect towards the physico-chemical properties of the activated carbon. The effect of surface area of palm kernel shell activated carbon (PKSAC) framework towards the PCM also studied by the impregnation of the n-octadecane into different surface area of the activated carbon treated with different H3PO4 concentration. The result shows that the PKSAC treated with 20% H3PO4 gave the highest value of 1169 m2g-1 and average pore size of 27 Å. In general, this study shows the best activation temperature, holding time and treatment of H3PO4 in the preparation of PKSAC was 500 oC, 2 h and 20% H3PO4 respectively. In addition, the specific surface area plays a crucial role towards the properties of the resulting SSPCM prepared

Palm Kernel Shell Activated Carbon as an Inorganic Framework for Shape-Stabilized Phase Change Material

The preparation of activated carbon using palm kernel shells as the precursor (PKSAC) was successfully accomplished after the parametric optimization of the carbonization temperature, carbonization holding time, and the ratio of the activator (H3PO4) to the precursor. Optimization at 500 °C for 2 h of carbonization with 20% H3PO4 resulted in the highest surface area of the activated carbon (C20) of 1169 m2 g−1 and, with an average pore size of 27 Å. Subsequently, the preparation of shape-stabilized phase change material (SSPCM-C20) was done by the encapsulation of n-octadecane into the pores of the PKSAC, C20. The field emission scanning electron microscope images and the nitrogen gas adsorption-desorption isotherms show that n-octadecane was successfully encapsulated into the pores of C20. The resulting SSPCM-C20 nano-composite shows good thermal reliability which is chemically and thermally stable and can stand up to 500 melting and freezing cycles. This research work provided a new strategy for the preparation of SSPCM material for thermal energy storage application generated from oil palm waste

Shape-stabilized phase change material preparation for thermal energy storage application

This work was conducted to see the behavior of n-octadecane PCM towards different palm kernel shell activated carbon (PKSAC) prepared as shape-stabilized phase change material (SSPCM) for thermal energy storage (TES) application. The different PKSAC was identified from different amount of H3PO4 treatment given to palm kernel shell from 0, 5, 10, 20, 30 and 40% before activation. The impregnation of n-octadecane with the different PKSAC produced SSPCMs that expressed different physico-chemical characteristics. The BET surface area shows the obvious changes of value before and after impregnation which proves that the PKSAC is very suitable framework for the n-octadecane. The most obvious changes show in the graph is C20 by having the highest surface area compared to the others which is 1169 m2g-1 and decreased to 2 m2g-1. The X-ray diffractometer, field emission scanning electron microscope and FESEM images prove that the n-octadecane was successfully impregnated into the pores of AC without chemical interaction between the AC and n-octadecane. The SSPCM nanocomposite shows that the PKSAC is thermally good framework material for noctadecane observed by raman spectroscopy, TGA/ DTG thermal analysis, differential scanning calorimeter and leakage study

Enzymatic Pretreatment Improved the In Vitro Ruminal Degradability of Oil Palm Fronds

This study aims to increase the in vitro ruminal degradability of oil palm fronds (OPFs) through enzymatic pretreatment. The isolated fungi were selected based on their lignocellulosic degrading enzyme activities. Eleven fungi were successfully isolated, and their enzyme activities were evaluated. Three fungi, F1, F2 and F4 were selected, and they were identified as Trichoderma harzianum MK027305, Trichoderma harzianum MK027306 and Fusarium solani MK027309, respectively. The highest total gas and methane production was produced when OPFs were pretreated with an enzyme extract from 15 and 30 days of solid-state fermentation of T. harzianum MK027305 and T. harzianum MK027306, respectively. Meanwhile, OPFs pretreated with an enzyme extract from F. solani MK027309 after 45 days of solid-state fermentation produced the highest amount of volatile fatty acids. The pretreatment using the enzymes extracted from 45 days of solid-state fermentation of F. solani MK027309 increases the apparent rumen degradable carbohydrate (ARDC) by 35.29% compared to unpretreated OPF. This study showed that pretreatment of the OPFs using selected fungi’s enzymes increases the volatile fatty acid production and in vitro ruminal degradability of OPF, hence improving livestock production via increased utilization of agricultural by-products with minimal impact on the production cost

Empagliflozin in Patients with Chronic Kidney Disease

Background The effects of empagliflozin in patients with chronic kidney disease who are at risk for disease progression are not well understood. The EMPA-KIDNEY trial was designed to assess the effects of treatment with empagliflozin in a broad range of such patients. Methods We enrolled patients with chronic kidney disease who had an estimated glomerular filtration rate (eGFR) of at least 20 but less than 45 ml per minute per 1.73 m(2) of body-surface area, or who had an eGFR of at least 45 but less than 90 ml per minute per 1.73 m(2) with a urinary albumin-to-creatinine ratio (with albumin measured in milligrams and creatinine measured in grams) of at least 200. Patients were randomly assigned to receive empagliflozin (10 mg once daily) or matching placebo. The primary outcome was a composite of progression of kidney disease (defined as end-stage kidney disease, a sustained decrease in eGFR to < 10 ml per minute per 1.73 m(2), a sustained decrease in eGFR of & GE;40% from baseline, or death from renal causes) or death from cardiovascular causes. Results A total of 6609 patients underwent randomization. During a median of 2.0 years of follow-up, progression of kidney disease or death from cardiovascular causes occurred in 432 of 3304 patients (13.1%) in the empagliflozin group and in 558 of 3305 patients (16.9%) in the placebo group (hazard ratio, 0.72; 95% confidence interval [CI], 0.64 to 0.82; P < 0.001). Results were consistent among patients with or without diabetes and across subgroups defined according to eGFR ranges. The rate of hospitalization from any cause was lower in the empagliflozin group than in the placebo group (hazard ratio, 0.86; 95% CI, 0.78 to 0.95; P=0.003), but there were no significant between-group differences with respect to the composite outcome of hospitalization for heart failure or death from cardiovascular causes (which occurred in 4.0% in the empagliflozin group and 4.6% in the placebo group) or death from any cause (in 4.5% and 5.1%, respectively). The rates of serious adverse events were similar in the two groups. Conclusions Among a wide range of patients with chronic kidney disease who were at risk for disease progression, empagliflozin therapy led to a lower risk of progression of kidney disease or death from cardiovascular causes than placebo