Journal of the Pakistan Institute of Chemical Engineers

Comprehensive chemical profiling and biological activities of Tinospora malabarica: Implications for herbal drug development and quality control

2026-03-03T15:58:26+05:00

This study investigates the chemical composition and biological activities of a significant medicinal plant species, Tinospora malabarica, Sindh region of Pakistan. Initially, the determination of physicochemical parameters was carried out to understand the general properties of plant. Phenolic compounds were identified using HPLC-PDA and 6 phenolics were detected in this species. Essential oils and volatile compounds were extracted through steam distillation. Analysis of each volatile constituent was done through GC-MS and 75 compounds were identified. Fatty acid profiling was conducted via GC-FID, and identified 19 fatty acids in T. malabarica. To evaluate the antioxidant capacity, BHT was used as control in DPPH assay. Antibacterial activity was evaluated by testing the extracts against five bacterial strains: Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Salmonella typhimurium, Staphylococcus aureus. The results provide a comprehensive understanding of this plant species' chemical composition and biological activities, highlighting its potential for the development of herbal drug formulations. Furthermore, the findings contribute to establishing quality control protocols for use of T. malabarica which is a raw materials used in herbal drug production.

Integrated biodiesel production and DES-based purification from animal fats: comparative effects of feedstock, alcohol and catalyst

2026-04-22T13:54:15+05:00

Biodiesel is a sustainable alternative to fossil fuels; however, the high cost of feedstock and downstream purification processes remains a significant challenge. This work presents an integrated approach for biodiesel production from chicken and beef fats using an alkali-catalyzed transesterification process followed by purification with a deep eutectic solvent (DES) composed of tetrabutylammonium bromide (TBABr) and oxalic acid. The effects of feedstock type, alcohols (methanol and ethanol), and catalysts (KOH, NaOH, and Ca(OH)₂) were comparatively evaluated. The highest biodiesel yield, 91 ± 1%, was achieved using chicken fat, methanol, and NaOH under optimized conditions (60 ^oC, 1 hour, 400 rpm, a 6:1 alcohol-to-oil molar ratio). DES purification reduced acid value by ~37%, demonstrating effective impurity removal. Product quality was further validated through FT-IR, GC-FID, and physicochemical property analysis based on ASTM standards. The study demonstrates that the selection of feedstock, alcohol, and catalyst significantly influences reaction kinetics, phase separation, and mass transfer during process performance. The proposed integrated approach provides an efficient and environmentally friendly strategy for biodiesel production and purification.

Kinetic and thermodynamic evaluation of plastic waste degradation for energy recovery

2025-12-01T13:06:20+05:00

Plastic consumption with effective recycling is essential for sustainable life-cycle management. In recent years, energy recovery and value-added product generation from plastic waste have gained increasing attention, with pyrolysis emerging as a promising thermochemical pathway for plastic degradation. This study investigates the thermokinetics of two waste plastic streams: mechanically recycled plastics, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polyethylene terephthalate (PET), and landfill-dumped mixed waste plastic (MWP) and multilayer plastic (MLP), to evaluate operational parameters for pyrolysis and hydrothermal liquefaction (HTL) to optimize their conversion into valuable products. Thermogravimetric analysis (TGA), conducted at a heating rate of 10 °C/min, revealed that HDPE exhibited the highest weight loss (98%) at a peak temperature of 494 °C with a degradation time of 13 minutes. PET has a low conversion rate (80.53%) than HDPE, LDPE, and PP, resulting in a larger residue. The Coats-Redfern model-fitting method, applied with various models, was used to calculate the kinetic triplet and thermodynamic properties. Among the tested models, F1 (First-order) and F2 (Second-order) reaction models were identified as the most suitable for recycled plastics, while D2 (two-dimensional diffusion) was found to be appropriate for dumped plastics. The activation energies of mechanically recycled plastics were estimated to range from 154 to 295 kJ/mol, whereas landfill-dumped plastics ranged from 117 to 171 kJ/mol. Analysis of degradation temperature, duration, and weight loss (%) obtained from TGA provided a reference point for determining the optimal operating parameters (reaction time and temperature) for pyrolysis, thereby minimizing solid residue and enhancing the efficiency of plastic conversion into oil and gases.