Synthesis of urea impregnated ruber wood biochar for retention of nitrogenoues nutrient in soil

Urea is one of the nitrogen sources for plants to grow. Upon its application to soil, mineralisation takes place, where urea [(NH2)2CO] is hydrolysed and converted to an intermediate compound known as ammonium carbonate [(NH4)2CO3]. Subsequently, it is converted to ammonium ions (NH4+) by urease activities for plant uptake. The remaining hydroxide ions (OH-) increase the soil's pH and release ammonia (NH3), a greenhouse gas produced after the reaction with NH4+. Some portions of NH4+ will be oxidised by oxygen in the air and converted to nitrite (NO2-) and nitrate (NO3-) by bacteria. The mobility of NO3- causes leaching by the run-off of ground water and surface water that leads to eutrophication. Many efforts have been carried out to address this matter. However, there are still some research gaps and room for improvement. Biochar derived from rubber wood sawdust (RWSD) is introduced to be impregnated with urea to slow down the mineralisation and reduce nitrogen losses. The main objective of this research is impregnation of urea onto biochar for nitrogenous nutrient retention in soil. The characterisation of biochars focused on physiochemical characteristics such as X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared (FT-IR) spectroscopy, Boehm titration, pH alkalinity, scanning electron microscopy (SEM) and SEM with energy-dispersive X-ray (SEM-EDX) spectroscopy. The porosities and acidic functional groups such as carboxylic (--COOH) groups are hypothesised to enhance the physio-chemi adsorption of urea onto biochar. The impregnation of urea onto biochar is performed by urea dissolution and recrystallisation with biochars content ranging from 2 % to 15 %. The ammonium and nitrate retained in soil after four weeks incubation are analysed by the first order kinetic model. It is observed that the mineralisation rate constant of urea is 54.4 %/week, higher compared with that of the impregnated samples at 5 % biochar obtained at 300 ºC, which is 25.9 %/week and urea impregnated biochar sample produced at 700 ºC with 10 % of impregnation, which is 28.9 %/week. In addition, the result from the total nitrogenous nutrient retention show that the percentage of biochar produced at 300 ºC ranging from 3 % to 7 % and those at 700 ºC ranging from 2 to 10 % are able to retain 15 % more nitrogenous compound than pristine urea. Moreover, ammonia volatilisation also indicated significant reduction after impregnation with the biochars with percentage ranging from 4 to 10 %, and exhibited the maximum ammonia loss of 35 % at 7.5 % of biochar. The reduction of ammonia emission is due to better nitrogen retention in soil upon impregnation. In addition, the trend nitrogenous nutrient retention in soil shows inverse quadratic relationship for both biochar while the ammonia emission shows a normal quadratic relationship. Hence, the emission of nitrous oxide is reported very minimal compared to pristine urea. Finally, the water column analysis revealed that the influence of urea impregnation with urea is negligible for ammonium. Nevertheless, the leaching of nitrate declined in the urea impregnated biochar sample due to the biochar contribution in reducing the mobility of nitrate in soil

Urea impregnated biochar to minimize nutrients loss in paddy soils

Rubber wood sawdust (RWSD) is converted into a porous form of biochar through the slow pyrolysis process. In this study, it is used as a green binder to bind the urea together and form a fertilizer. The objective of the current research is to investigate the effect of biochar impregnation with urea on the N-nutrients retention in soils. The biochars were produced at heating temperatures of 300 °C and 700 °C for 3 hours with continuous nitrogen gas purging at 30 ml/min and a constant heating rate of 5 °C/min. The obtained biochars were characterized by XRD, Boehm titration, pH alkalinity, BET specific surface area and SEM. Boehm titration demonstrated a reduction of acidic functional groups with the increase of heating temperature, recorded as 1.3 and 0.3 mmol/g respectively for 300 °C and 700 °C. Conversely, biochar produced at higher temperature was reported to have a larger specific surface area of 5.4 m2/g. The impregnation was carried out on both biochars produced with molten urea. Results from mineralization showed that the sample with impregnation retained more nutrients in the soil compared to the un-impregnated sample, manifesting biochar as a potential material to be impregnated with urea for slow release and better nutrients retention in s

Influence of heating temperature and holding time on biochars derived from rubber wood sawdust via slow pyrolysis

Biochar samples were produced from rubber wood sawdust (RWSD), which is a by-product from sawmills, via slow pyrolysis. Biochar is a potential additive for agricultural soil as a soil amendment and for agronomics. The approach proposed in the current study considers the effects of heating temperature and holding time on the surface functional groups and morphologies of RWSD-derived biochars. The pyrolysis was performed in a vertical tube furnace heated at 5 °C/min from room temperature to maximum heating temperatures of 300 °C, 400 °C, 500 °C and 700 °C under nitrogen gas purging at a rate of 30 ml/min. Two sets of biochars were produced with holding times of (i) 1 h and (ii) 3 h. Proximate and ultimate analyses were performed on the raw RWSD using thermogravimetric analysis (TGA) and carbon–hydrogen–nitrogen (CHN) elemental analysis. The influence of heating temperature and holding time on biochar surface functional groups and porosities was investigated using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Boehm titration, pH alkalinity, Brunauer–Emmett–Teller (BET) surface area analysis, scanning electron microscopy (SEM) and SEM with energy-dispersive X-ray (SEM–EDX) spectrocopy. The FT-IR spectra indicated the presence of acidic functional groups, such as carboxylic, phenolic and lactonic groups, and these groups were quantified by Boehm titration. The number of acidic functional groups decreased as the heating temperature and holding time increased. The maximum amount of acidic functional groups was determined to be 1.9 mmol/g at 300 °C for a 1-h holding time compared to 1.3 mmol/g for a 3-h holding time and 1.0 mmol/g with a 1-h holding time at 700 °C. All of the biochars produced at heating temperatures above 400 °C were alkaline, and the pH value increased as the heating temperature and holding time increased. The biochar produced at 300 °C with a 1-h holding time had a pH of 6.72 and the sample produced with a 3-h holding time had a pH of 7.67. In addition, the sample produced when the temperature was increased to 700 °C with a 1-h holding time had a pH of 11.44. The BET surface area analysis reported maximum values of 5.49 m2/g, and the total pore volume was 0.0097 cm3/g at a heating temperature of 700 °C with a 3-h holding time. SEM micrographs clearly showed the development of well-defined pores in the biochars, and the SEM–EDX spectra indicated localised carbon and oxygen content in all the samples. The results indicated that biochars produced from RWSD are potentially beneficial as soil amendments. However, an extensive study of biochar sustainability is worth investigating

Pathogenic copy number variants and SCN1A mutations in patients with intellectual disability and childhood-onset epilepsy

Background Copy number variants (CNVs) have been linked to neurodevelopmental disorders such as intellectual disability (ID), autism, epilepsy and psychiatric disease. There are few studies of CNVs in patients with both ID and epilepsy. Methods We evaluated the range of rare CNVs found in 80 Welsh patients with ID or developmental delay (DD), and childhood-onset epilepsy. We performed molecular cytogenetic testing by single nucleotide polymorphism array or microarray-based comparative genome hybridisation. Results 8.8 % (7/80) of the patients had at least one rare CNVs that was considered to be pathogenic or likely pathogenic. The CNVs involved known disease genes (EHMT1, MBD5 and SCN1A) and imbalances in genomic regions associated with neurodevelopmental disorders (16p11.2, 16p13.11 and 2q13). Prompted by the observation of two deletions disrupting SCN1A we undertook further testing of this gene in selected patients. This led to the identification of four pathogenic SCN1A mutations in our cohort. Conclusions We identified five rare de novo deletions and confirmed the clinical utility of array analysis in patients with ID/DD and childhood-onset epilepsy. This report adds to our clinical understanding of these rare genomic disorders and highlights SCN1A mutations as a cause of ID and epilepsy, which can easily be overlooked in adults

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Microwave Absorbing Material Using Rubber Wood Sawdust

Abstract - A flat microwave absorber working at frequency 1.8GHz was developed by impregnation of activated carbon and polyurethane. The activated carbon is prepared from the conversion of rubber wood sawdust through chemical activation process using ZnCl2 solution as the precursor agent. The process involves leaching, heating and washing. The impregnation ratio between ZnCl2 and rubber wood sawdust were at 1:1, 1.5:1 and 2:1. All samples are heated at temperature of 500o C for 60 minutes. It was found that the chemical activation at impregnation ratio of 2:1 produced high purity activated carbons with 79 percent carbon content. Based on the BET analysis, the surface area of the powder for impregnation ratio 1.5:1 reported highest value of 1301 m2 /g, this formulation is selected for making microwave absorber and it was reported that the reflection loss is recorded 10dB at 1.8 GHz

SLOW PYROLYSIS AND CHARACTERIZATION OF SURFACE FUNCTIONAL GROUPS FOR BIOCHAR DERIVED FROM RUBBER WOOD SAWDUST

Rubber wood sawdust (RWSD), an agricultural by-product generated from conversion of wood logs to sawn timber in the rubber wood industry. It is utilized as the low or zero cost starting material for the preparation of biochar to be applied as soil amendment. Prior to the pyrolysis process of raw RWSD, carbon-hydrogen-nitrogen (CHN) analysis and thermal gravimetric analysis were carried out for elemental and thermal stability analysis respectively. The biochar is pyrolyzed by using a conventional tube furnace heated at temperature between 300°C to 700°C at a heating rate of 5°C/min for 3 hours under the flow of nitrogen gas. The pyrolyzed materials were ground into fine powder for X-ray Diffraction (XRD) analysis, alkalinity test, Fourier Transform Infrared spectroscopy (FTIR) and Boehm titration. The FTIR spectra showed the amount of functional groups reduce with the increase of heating temperatures. The increase in temperature also caused the surface negative charge of biochar reduced from 1.3mmol/g to 0.3mmol/g as detected by Boehm titration test with 0.1N natrium hydroxide (NaOH) solution. These results might be due to the reduction of functional groups such as carboxyl, lactone and phenol groups through thermal decomposition process

The Effect of the Carbon to the S11 Measurement on the Pyramidal Microwave Absorbers

The purpose of this work is to determine the absorption effect by using carbon as absorbing material. It will be used in anechoic chamber in order to avoid reflections that occur on the wall of the chamber. From polystyrene, the absorbers are cut into pyramidal shaped. The pyramidal shaped is chosen because it could meet the specified industrial standards which can work well at microwave frequency. To verify the performance of the absorber, a measurement is conducted to determine the absorption rate in frequency range 1 to 10 GHz. The absorber also compared to commercial absorber. The results shows carbon is a good material to absorb the microwave energy. The absorber that has been developed is a low cost with reliable performance