This paper presents an approach for hydrolyzing cellulose nanocrystals from oil palm empty fruit bunch (OPEFB) presented through hydrochloric acid hydrolysis under sonication–hydrothermal conditions. Differences in concentration, reaction time, and acid-to-cellulose ratio affect toward the yield, crystallinity, microstructure, and thermal stability were obtained. The highest yield of cellulose nanocrystals up to 74.82%, crystallinity up to 78.59%, and a maximum degradation temperature (T_max) of 339.82 °C were achieved through hydrolysis using 3 M HCl at 110 °C during 1 h. X-ray diffraction analysis indicated a higher diffraction peak pattern at 2θ = 22.6° and a low diffraction peak pattern at 2θ = 18°. All cellulose nanocrystals showed a crystalline size of under 1 nm, and it was indicated that the sonication–hydrothermal process could reduce the crystalline size of cellulose. Infrared spectroscopy analysis showed that a deletion of lignin and hemicellulose was demonstrated in the spectrum. Cellulose nanocrystal morphology showed a more compact structure and well-ordered surface arrangement than cellulose. Cellulose nanocrystals also had good thermal stability, as a high maximum degradation temperature was indicated, where CNC-D1 began degrading at temperatures (T₀) of 307.09 °C and decomposed (T_max) at 340.56 °C.

This research has succeeded in developing a Lead (II) –Ion-selective electrode (Pb²⁺-ISE) sensor based on poly-tetrahydro furfuryl acrylate (pTHFA) films free plasticizers utilizing photo-polymer technique. The Pb²⁺-ISE has a performance that includes a linear range of 0.1–10⁻⁵ M, Nernstian number 26.5–29.8 mV/dec and LOD 3.24–3.98 (× 10⁻⁶) M, where the optimum composition between KTpClPB lipophilic salt with leads (IV) ionophore is 1:1 mole ratio. The Pb²⁺-ISE sensor also shows a relatively good selectivity value (Log K^pot_a,b) against several interfering ions including K⁺ −6.5 ± 0.3, Na⁺ −6.2 ± 0.1, NH₄⁺ −6.7 ± 0.1, Mg²⁺ −12.7 ± 0.2, Cu²⁺ −4.2 ± 0.5 and Cd²⁺ −6.1 ± 0.2, where the response of the Pb²⁺-ISE sensor is stable at pH 3–8. In this study, the Pb²⁺-ISE sensor shows validation test results that are comparable to measurements using atomic absorption spectroscopy (AAS) devices using artificial solutions and real sample. The results of testing with artificial solutions successively produced Pb²⁺ concentrations of 9.5 ± 0.3, 52.5 ± 1.7, and 100.8 ± 2.5 ppm, while for real samples the Cisadane river was 0.0025 ± 0.45 ppm and the refueling station was 18.15 ± 16.74 mg/kg soil sample.

This study is in relation to preliminary investigation of aluminium-air battery using disposable soft drink cans as aluminium source for anode. The cathode uses commercial porous carbon sheet to trap oxygen from air. This work applies a commercial cashing to place carbon cathode, electrolyte, Arabic gum polymer, and aluminium anode in a sandwich-like arrangement to form the aluminium-air battery. The Arabic gum as electrolyte polymer membrane protects anode surface from corrosion due to aluminium oxide formation. The study result shows that the battery discharge test using constant current loading of 0.25 mA yields battery capacity of 0.437 mAh with over 100 minute battery life times at 4M NaOH electrolyte and 20 % Arabic gum polymer as the best performance in this investigation. This study gives significant advantage in association with beneficiation of disposable soft drink cans from municipal solid waste as aluminium source for battery anode.

This research has successfully fabricated ion selective electrode (ISE) for Pb²⁺ using castor oil (Ricinus communis L.)-based polyurethane (PU) membrane with 1,10-phenanthroline as the active agent. The sensitivity of the Pb²⁺ ISE obtained is 27.25 mV/decade with a linear range of [Pb(NO₃)₂] of 10⁻¹⁰–10⁻⁵ M and a coefficient of determination (R²) of 0.959. The system response reaches stability after 25 s of measurement. The Pb²⁺ has a detection limit of 10⁻¹⁰ M and gives a stable response at pH 7–8 with a 15-day lifetime. The investigation of the selectivity of the ISE was performed using the mixed solution method with log Kij values of Ca²⁺ > K⁺ > Mg²⁺ > Cu²⁺ > Fe³⁺ > Cr³⁺> Zn²⁺ > Cd²⁺. The Pb²⁺ ISE shows acceptable reproducibility and repeatability with standard deviation values of 0.065 and 0.0079, respectively. Fourier transform infrared (FT-IR) spectra confirmed that 1,10-phenanthroline was responsible for the formation of the Pb²⁺ ion entrapment via complexation. Other characterizations (crystallinity, micro-surface morphology, and mechanical strength) suggest the degradation of the membrane structure integrity after the application. The analysis results of Pb levels using the Pb²⁺ ISE in artificial and wastewater samples were not significantly different from the atomic absorption spectroscopy (AAS) measurement.

Nanoparticles of the conducting polymer polypyrrole in toluene sulfonic acid (PPy/TSA) were synthesized and characterized. The polymerization was process carried out in situ using ammonium persulfate (APS) as an oxidant. The particles were synthesized by varying the dopant concentration of para-toluene sulfonic acid over five sulphonic acid concentrations. The main objective of this study was to examine the effect of TSA dopant concentrations on the properties of polypyrrole nanoparticles. Understanding nature and characteristics of polypyrrole/TSA nanoparticles are important in determining whether the nanoparticles have the potential to be a component in the manufacture of fuel cells. The conducting polymer particles synthesized in this study were characterized using a particle analyzer, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), spectroscopy UV-visible (UV-vis), thermogravimetric analysis (TGA) and electrical conductivity measurement. XRD shows that the particles generated possessed an amorphous structure, as also indicated by SEM images revealing the formation of aggregated and granular composite particles. Furthermore, the FTIR peak between 1273 and 1283cm-1 indicated that sulfonic acids (SO3-) groups were present in the structure of PPy. The size of the PPy/TSA nanoparticles was determined to be approximately 24-51 nm, and their conductivity measured to be 1.3 x 10-1 S/cm.