This study explores de-oiled rice bran (DORB), an agro-industrial by-product, as a precursor for the preparation of porous activated carbon. The study assesses the performance of the synthesized activated carbon (AC) in removing malachite green(MG) dye from aqueous solutions, with a focus on developing economically viable and sustainable adsorbents for wastewater treatment. AC was synthesized using a combined thermal and chemical modification process with H3PO4, eliminating the need for separate activation steps. This approach reduced preparation time and energy consumption. The resulting activated carbon possessed a surface area of 465 m(2)g(-1)and an average pore size of 5.0872 nm. Characterization was performed using SEM, FTIR, EDAX, and pH(pzc)techniques. The adsorption performance was studied under varying pH (3.0-9.0), initial MG concentration (10-50 mg L-1), adsorbent dosage (0.1-0.6 g), contact time (0-30 min), and temperatures (303-333 K). The adsorption behaviour followed the Freundlich isotherm model, and the kinetics were well described by the pseudo-second-order model. The highest adsorption capacity was 70.92 mg g(-1). Thermodynamic analysis revealed spontaneous (Delta G<0), endothermic (Delta H>0), and favourable (Delta S>0) adsorption. Regeneration studies identified 0.2 M HCl as an effective solvent for De-oiled rice bran activated carbon (DORBAC) recovery.
Macitentan is an approved orally active endothelin receptor antagonist used for the treatment of pulmonary arterial hypertension (PAH). It is poorly soluble and also exerts slow absorption after oral administration. Endothelins play a major role in vascular hemostasis and ocular inflammatory reactions. Self-nanoemulsifying drug delivery systems (SNEDDS) of macitentan were prepared using an oil-surfactant mix, and PEG 600, Transcutol HP, or ethanol as co-surfactant. The potentiality of ocular anti-inflammation has also been examined after the administration of macitentan delivery systems of self-nanoemulsion in a carrageenan-induced (upper palpebral region: 100 mu l, 3 % w/v) rabbit eye model. Nanoemulsion regions were identified of macitentan-loaded SNEDDS formulation after constructing ternary diagrams. Formulation containing Transcutol HP (MT2) exhibited globule size (47.35 +/- 0.295 nm), PDI (0.191 +/- 0.008), and zeta potential (-12.0 +/- 0.81) with highest corneal permeation of about 90 % in 6 h compared to PEG 600 as cosurfactant. Improved corneal permeation has been observed after topical application of self-nanoemulsion containing Transcutol HP. Symptoms of ocular inflammation disappeared within 1 h after MT2 instillation in carrageenan-induced rabbit eye whereas, more than 2 h of acute inflammation continued in the untreated eye. Macitentan self-nanoemulsion containing Transcutol HP could be used for the management of ocular inflammation.
Kinetic modeling plays a central role in interpreting experimental behaviour and supporting reactor design in biofuel production systems. Commonly applied models range from empirical curve-fitting equations to mechanistically derived growth models, each constructed upon distinct theoretical assumptions. However, inappropriate model selection can compromise interpretability and predictive reliability beyond the experimental domain. Thus, kinetic model selection should be guided by scientific suitability rather than conventional or statistical convenience. This review provides a critical and comparative evaluation of kinetic models applied in biofuel production systems by comparing their mechanistic basis, parameter identifiability, data requirements, and extrapolation capability. Empirical models such as First-order, Logistic and Gompertz-type models are assessed for their descriptive accuracy but limited mechanistic insight. Growth-based models like Monod model capable of representing substrate consumptions, evaluated for their ability to represent biological and biochemical constraints, while highlighting persistent challenges related to data availability, parameter identifiability, and validation. More structured and hybrid approaches, such as Luedeking-Pirettype model examined for their ability to couple microbial growth and product formation under data-rich conditions. Systematic comparison shows that model suitability is governed primarily by research objective, system complexity, and experimental resolution rather than by conventional usage. On this basis, a decision-oriented framework is developed to guide context-specific kinetic model selection to enhance methodological rigor in biofuel process analysis.
The Solvent Production Plant (SPP) at HWP Tuticorin generates hypersaline and organic contaminant effluents with elevated Chemical Oxygen Demand (COD) of 26,800 ppm, exceeding the regional Tamil Nadu Pollution Control Board (TNPCB) discharge limits at India. This study presents a comprehensive 4E (Environment, Energy, Exergy, Economics) parametric assessment of ferric chloride (FeCl3) precipitation and activated charcoal adsorption for optimizing the treatment of solvent production effluents. The chemical based FeCl3 precipitation method of treating effluent reduces COD to 9,650 ppm in single treatment but requires two to three successive precipitation cycles to achieve the Tamil Nadu Pollution Control Board (TNPCB) discharge standard. In contrast, fixed-bed activated charcoal adsorption reduces the COD by approximately 50%, while maintaining Total Dissolved Solids (TDS), generating no sludge, and allowing adsorbent regeneration using 0.3 M HCl, thereby improving process sustainability and economic performance. Based on the comparative 4E evaluation, a hybrid integrated treatment methodology is proposed in which activated charcoal adsorption is employed as a pre-treatment stage to reduce the initial organic load, followed by FeCl3 precipitation as a polishing treatment to achieve the required discharge standards. This integrated approach reduces chemical consumption, sludge generation, energy demand, and overall operating costs while improving treatment efficiency. The Rotary Vacuum Drum Filter (RVDF) of FeCl3 precipitation effectively separates ferric hydroxide sludge generated during the treatment process. The novelty of this work lies in the application of a 4E assessment framework to develop an integrated treatment strategy for hypersaline nuclear solvent effluents, providing a practical and sustainable solution for industrial effluent management.
This work presents the synthesis and characterization of a coconut shell waste-derived nanocellulose-based hydrogel for green agriculture. The hydrogel was designed to enhance water retention of soil and deliver controlled release of nutrients, addressing the major problems of drought and fertilizer inefficiency. Nanocellulose was prepared through acid hydrolysis after alkaline and bleaching treatment and cross-linked with citric acid to yield a urea-loaded hydrogel. Fourier Transform Infrared spectra verified the integrity of cellulose functional groups and the formation of new -COO- bonds, evidencing good crosslinking and urea incorporation. X-ray diffractogram evidenced prominent crystalline peaks at 2 theta approximate to 15 degrees and 22.5 degrees, signifying partial retention of cellulose I structure with reduced crystallinity, augmenting swelling and water-retention capacity. Scanning Electron Microscope images exhibited a sharp, porous, and networked structure that supports water uptake, nutrient transfer, and mechanical strength. Hydrogel exhibited a 50% increase in water retention and an 88% degree of nutrient release efficiency, greatly supporting soil parameters such as nitrogen level and water content. Soil analysis after treatment showed high ammoniacal nitrogen (7.6 mg/kg) and a notable rise in total Kjeldahl nitrogen (13.1%), confirming efficacy of nutrient delivery. These results set the hydrogel's dual function as a moisture regulator and slow-release fertilizer system. Overall, the nanocellulose hydrogel derived from coconut shells is an economically scaled, biodegradable, and environmentally friendly material for smart agriculture with benefits towards water conservation, reduced fertilizer loss, and climate-stressed crop productivity in a sustainable way.
