Vaibhav A. Edlabadkar

Corrosion and paraffin deposition are the two major problems in the oil and gas industry. While corrosion impacts the integrity, safety, and longevity of structures, the formation of paraffin crystals can cause unwanted production challenges that often lead to reduced production volumes or production downtime. However, most common corrosion and paraffin inhibitors have high environmental footprints in oilfields. This study addresses this challenge by introducing waste cooking oil (WCO)-based imidazolines as corrosion and paraffin inhibitor. Imidazoline was synthesized using WCO and aminoethylethanolamine (AEEA) under atmospheric conditions. The formed imidazoline was characterized by FTIR and GC-FID with a >95% conversion rate. Their corrosion and paraffin inhibition performance was analyzed at different concentrations by rotating cylinder electrode (RCE) and coldfinger apparatus, respectively. WCO-imidazoline showed corrosion inhibition of up to 98% and paraffin inhibition of up to 51% in the oilfield samples. The results showed that the use of WCO is a good alternative for the synthesis of environmentally friendly corrosion and paraffin inhibitors with high inhibition efficiencies.

Quantitative, reversible water vapor sorption is in rising demand for applications ranging from home appliances to atmospheric water harvesting. However, most sorbents suffer from low water-uptake capacities, nonreusability, and especially high regeneration temperatures. This study addresses this challenge by introducing polybenzoxazine- (PBO) and polybenzodiazine-derived (PBDAZ) carbon aerogels as reversible high-capacity desiccants. PBO and PBDAZ aerogels were prepared from structurally related monomers via HCl-catalyzed ring opening polymerization. Both types of aerogels were first aromatized at 200-240 °C under air or O₂ and then were carbonized at 800 °C under Ar. These as-prepared carbon aerogels were further etched at 1000 °C under flowing CO₂. Both as-prepared and CO₂-etched carbon aerogels were characterized with CHN elemental analysis, XPS, and gas (N₂ and CO₂) sorption porosimetry. Their water-uptake capacity was assessed at 273, 298, and 313 K. The long-term performance and cycling stability of these aerogels were studied by switching their surrounding environment between a highly humid and a dry atmosphere (99% and 10% relative humidity, respectively), staying for 24 h in each environment. No performance deterioration was detected after 50 full cycles (100 days). Carbon aerogels from both PBDAZ and PBO showed significant water-uptake capacities (43% and 42% w/w, respectively). However, CO₂-etched PBDAZ- and PBO-derived carbon aerogels showed among the highest water uptake capacities reported in the literature, reaching 117% w/w and 140% w/w at 298 K, respectively (all values at 298 K). Water uptake started with hydrogen bonding to the O and N lining the concave surfaces of the pores and continued until micropores and mesopores were filled with water. Adsorbed water was released quantitatively at room temperature just by reducing the relative humidity of the environment.

Wax deposition, driven by the crystallization of long-chain n-alkanes, poses severe challenges across industries such as petroleum, oil and natural gas, food processing, and chemical manufacturing. This phenomenon compromises flow efficiency, increases energy demands, and necessitates costly maintenance interventions. Wax inhibitors, designed to mitigate these issues, operate by altering wax crystallization, aggregation, and adhesion over the pipelines. Classic wax inhibitors, comprising synthetic polymers and natural compounds, have been widely utilized due to their established efficiency and scalability. However, synthetic inhibitors face environmental concerns, while natural inhibitors exhibit reduced performance under extreme conditions. The advent of nano-based wax inhibitors has revolutionized wax management strategies. These advanced materials, including nanoparticles, nanoemulsions, and nanocomposites, leverage their high surface area and tunable interfacial properties to enhance efficiency, particularly in harsh environments. While offering superior performance, nano-based inhibitors are constrained by high production costs, scalability challenges, and potential environmental risks. In parallel, the development of “green” wax inhibitors derived from renewable resources such as vegetable oils addresses sustainability demands. These eco-friendly formulations introduce functionalities that reinforce inhibitory interactions with wax crystals, enabling effective deposition control while reducing reliance on synthetic components. This review provides a comprehensive analysis of the mechanisms, applications, and comparative performance of classic and nano-based wax inhibitors. It highlights the growing integration of sustainable and hybrid approaches that combine the reliability of classic inhibitors with the advanced capabilities of nano-based systems. Future directions emphasize the need for cost-effective, eco-friendly solutions through innovations in material science, computational modeling, and biotechnology.