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Two low-cost wastes, banana pith (BP) and cockle shells (CS) were explored towards methylene blue (MB) removal. The performance of cockle shells-treated banana pith (CS-BP) in MB removal was compared with untreated BP and commercially Ca(OH)2-treated BP (Ca(OH)2-BP). The adsorption efficacy was following the order of BP < CS-BP < Ca(OH)2-BP, indicating the positive role of alkaline treatment towards MB removal and great potential of CS as a low-cost activation material. The optimization of MB removal onto CS-BP was executed by response surface methodology (RSM) with three independent variables (adsorbent dosage (X1), initial pH (X2) and initial MB concentration (X3)), and the optimal condition was achieved at X1 = 1.17 g/L, X2 = pH 7 and X3 = 214 mg/L, with 87.32% of predicted MB removal. The experimental data well-fitted the pseudo-second-order kinetic (R2 > 0.99) and the Langmuir isotherm (R2 = 0.999) models, demonstrating the chemisorption and naturally homogeneous process. Thermodynamics study discovered that the MB removal by CS-BP is endothermic, feasible, spontaneous and randomness growth at a solid-solute interface. It is affirmed that CS could be employed as a low-cost activation material and CS-BP as a low-cost adsorbent.

Dry reforming of methane (DRM) which also known as CO2 reforming of methane is a well-investigated reaction to serve as an alternative technique to attenuate the abundance of greenhouse gases (CO2 and CH4). The syngas yielded is the main component for the liquid fuels and chemicals production in parallel with the fluctuating price of oil. Major researches were executed to seek for the well-suited catalysts before the commercialization of DRM can be realized. However, severe deactivation due to the carbon formation restricted the usage of promising Ni-based catalysts for DRM. Meanwhile, the deactivation on these catalysts can be associated with the operating conditions of DRM, which subsequently promoted the secondary reactions at different operating conditions. In fact, the parametric study could provide a benchmark for better understanding of the fundamental steps embodied in the CH4 and CO2 activation as well as their conversions. This review explores on the influences of the reaction operating parameters in term of the reaction temperatures, reactant partial pressures, feed ratios, and weight hourly space velocity (WHSV) on catalytic performance and carbon accumulation for the DRM.

Photocatalysis is a green chemical process that could partly solve energy and pollution issues. Catalysts such as cobalt titanate, CoTiO3, have intrigued scientists due to a visible light-responsive band gap of about 2.3 eV and a high valance band potential of about 2.35 eV that allow a remarkable oxidative activity. Nonetheless, CoTiO3 photocatalytic activity is limited by charge recombination, thus requiring modifications. For instance, the introduction of a second semiconductor allows improved charge separation and notable enhancement of the activity. Here we review interfacial engineering of CoTiO3 by introduction of a second semiconductor. We describe the synthesis and photocatalytic applications of bare and modified CoTiO3. Modified CoTiO3 composites are categorized into Type-I, Type-II, Z-scheme, and S-scheme heterojunctions, depending on the band structures of the composite. [ABSTRACT FROM AUTHOR]

In the current study, microwave-assisted glycerol polymerization for short-chain polyglycerol production was conducted unprecedentedly over low-cost catalyst, lithium-modified aluminium pillared clay (Li/AlPC) catalysts without the solvent. The influences of disparate reaction parameters such as the effects of Li loadings (10, 20, 30 wt.%), catalyst loadings (2, 3, 4 wt.%), operating temperatures (200, 220, 240 °C) and operating times (1–4 h) on the glycerol conversions, and polyglycerol yield (particularly for diglycerol and triglycerol), were elucidated. The fresh catalysts were subjected to physicochemical properties evaluation via characterization techniques, viz. N2 physisorption, XRD, SEM, NH3-TPD and CO2-TPD. In comparison, 20 wt.% Li/AlPC demonstrated the best performance under non-conventional heating, credited to its outstanding textural properties (an increase of basal spacing to 21 Ȧ, high surface area of 95.48 m2/g, total basicity of 34.48 mmol/g and average pore diameter of 19.21 nm). Within the studied ranges, the highest glycerol conversion (98.85%) and polyglycerol yield (90.46%) were achieved when catalyst loading of 3 wt.%, reaction temperature of 220 °C and reaction time of 3 h were adopted. The results obtained also anticipated the higher energy efficiency of microwave-assisted polymerization than conventional technique (>8 h), as the reaction time for the former technology was shorter to attain the highest product yield. The study performed could potentially conduce the wise utilization of surplus glycerol generated from the biodiesel industry. [ABSTRACT FROM AUTHOR]