Optimization of Phosphoric Acid Treatment Biochar using Response Surface Method

Biochar is derived from the crop residue as a multifunctional materials for agricultural applications and as a soil enhancer to improve soil fertility. The physical and chemical properties of biochar are improved via phosphoric acid treatment. The aim of this study is to optimize the acid treatment of biochar for two factor; 1) concentration of phosphoric acid and 2) heating temperature via Response Surface Methodology (RSM) by using Design Expert 10 software. A set of 11 experiments were carried out based on Central Composite Design (CCD) with three repetitions at center point. Hence, the responses were set in two factors; 1) pH and 2) negative surface charge. The biochar produced from slow pyrolysis process of rubber wood sawdust (RWSD) in a horizontal tube furnace heated at 5⁰C/minute from room temperature to maximum temperature of 400⁰C with holding time of 1 hour. Characterization of treated biochar was performed using Scanning Electron Microscopy (SEM) and SEM with EDX. Analysis of variance of the pH and negative surface charge indicated that the selected quartic model was significant with p-value of <0.05. Predicted parameters to obtain the maximum negative surface charge were 1 Mol of acid concentration and 85⁰C of heating temperature with desirability of 98%

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

EFFECT OF DIFFERENT COOKING TEMPERATURE AND ALKALINITY ON MECHANICAL AND MORPHOLOGICAL PROPERTIES OF COMPOSITE SHEET FROM DURIAN SHELL WASTE FIBRE

Temperature and alkalinity are the critical factors that contribute to the successful of soda pulping. These factors influence the length size and interfibre bonding of the fibre. In this paper, durian (Durio zibethinus Murray) shell composite sheet were prepared by conducting chemical pulping through soda method to study the effect of different pulping temperature and % of NaOH on the mechanical and morphological characteristics of durian shell composite sheet. Six sets of composite sheet were produced from six sets of pulping. The pulping processes were conducted at 140, 160 and 170°C with 17, 19 and 21% of active alkali. The mechanical properties of the durian shell composite sheet were analyzed through few standard TAPPI analyses which are tensile, tear, burst, folding endurance and paper bulk thickness. The results show that the highest reading of paper bulk thickness, tensile, tear and burst index, and also folding endurance were achieved at the pulping condition of 170°C with 21% of NaOH with the value of 1.3366 g/cm3, 54.151 NM/g, 6.648 m.Nm2/g, 2.517 k.Pam2/g and 170 no. of fold, respectively. Scanning electron microscopic analysis showed that morphological changes took place depending on the size and arrangement of the fibres in the composites sheet