Volume 12 Issue 1

Cellulose microfiber (MF) formation by electrospinning is affected by several factors. In this paper, fabrication of MF from oil palm mesocarp fiber (OPMF), a biomass residue abundantly available at the palm oil mill, was conducted by electrospinning. The effect of OPMF-cellulose solution properties on the spinnability of the solution was determined. Extracted cellulose from OPMF was dissolved in four different formulations of ionic liquids: (i) ([EMIM]Cl), (ii) ([EMIM][Cl):DMF, (iii) ([EMIM]Cl):([C10MIM][Cl]), and (iv) ([EMIM]Cl):([C10MIM][Cl]):DMF at cellulose concentrations of 1% to 9% (w/v). Scanning electron microscopy (SEM) analysis showed that MF formed had diameter sizes ranging from 200 to 500 nm. MF was formed only at 6% (w/v) cellulose concentration, when DMF was mixed in the solution. The results showed that cellulose concentration and viscosity played major roles in the spinnability of cellulose solution, in which too high viscosity of the cellulose solution caused failure of the electrospinning process and eventually affected the formation of MF. The characteristics of MF obtained herein suggest the potential of OPMF cellulose as a starting material for the production of MF.

Wood easily acquires a large amount of moisture when it is exposed to high-humidity conditions. The high moisture content influences the service life of wood. Thus, there is a need for an accurate, rapid, nondestructive, and simple measurement technique for wood’s moisture content. This investigation proposes a method to measure the moisture content of wood by the wood volumetric heat capacity using a transient hot wire (THW) technique. The moisture content was inferred from the change of the volumetric heat capacity before and after the wood acquired moisture; the volumetric heat capacity is the ratio of the thermal conductivity to the thermal diffusivity. The results were validated by the gravimetric method, displaying good agreement, with discrepancies within 4%.

This study examined the surface adhesion of ink on bio-composite materials that were produced using Luffa cylindrica fiber and epoxy. To increase the ink adhesion on the surface, two different production methods were developed. The surface roughness and the surface contact angle of the bio-composite surfaces manufactured by each method were determined. The printing was applied on the surface of the bio-composite materials using a screen-printing procedure. While keeping the printing conditions constant, two different ink types, environmentally friendly water-based ink and solvent-based ink, were utilized. As a result of this study, the two types of ink were adhered on the polymer-coated surface, and there was no adhesion on the uncoated surfaces. In addition, the printability of the solvent-based ink was better than the water-based one, and the image of the transfer had higher quality. When the water or solvent-based inks were applied on the surface, the groups capable of forming hydrogen bonds, which were present in both kinds of ink, constituted hydrogen bonds with the C=O and N-H groups. This resulted in better adhesion on the surface, which was due to the presence of the separator.

The degradation behavior was investigated for eco-composite nursery containers (NCs) prepared with rice husk and cornstarch adhesive modified with urea formaldehyde (UF) as a wet strength agent. The wet shear strength, water absorption capacities, and biological degradation of NCs within soil were also investigated. Quantitative analysis of the thermal degradation behavior of different NC versions was performed by thermo-gravimetric analysis (TGA). The results demonstrated that the introduction of the UF agent accelerated the soil degradation of the NCs matrix to a certain extent. The maximum cumulative mass loss was 51.1% when the UF content of NCs was 8 wt.%. Moreover, the dry strength of the mixed urea formaldehyde-cornstarch adhesive (UCA) was increased by 108.9% compared with cornstarch adhesive (CA). The results of this work indicate the improved biodegradability of the NC eco-composites, which could make them potential sustainable alternatives for conventional plastic pots.

The effects of physico-chemical parameters such as pH, temperature, and lead concentration on the efficiency of lead adsorption by rice husk ash were determined. Rice husk was incinerated at 800 °C for 6 h and then activated with 0.5 M HCl. Rice husk and rice husk ash (RHA) were characterized using scanning electron microscopy and X-ray fluorescence. Batch adsorption tests were conducted at different pH, temperature, and initial lead concentration. Kinetic studies were conducted at optimum pH of 3.0. The optimum lead removal of 80% was recorded at pH 3.0. Efficiency of lead removal by RHA decreased to 45% as pH increased to 9.0. Freundlich, Langmuir, Temkin, and Dubinin Radushkevich (D-R) isotherms performed acceptably well, with R2 values of 0.954≤R2≤0.991, 0.965≤R2≤0.996, 0.949≤R2≤0.979, and 0.970≤R2≤0.997, respectively. Lead removal efficiency decreased from 75% to 50% as temperature increased from 30 °C to 40 °C. The adsorption of lead by RHA was by ion exchange in the acidic pH range and by physisorption in the alkaline pH range. Thermodynamic studies revealed that the process was exothermic and spontaneous and further confirmed the feasibility of the process with -22.34≤∆G0≤-24.94. The intraparticle diffusion model and the pseudo first order kinetic model fit the experimental data very well, with average R2 values of 0.985 and 0.987, respectively.