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Aerogel is a special type of porous material with many outstanding physical and chemical properties, such as low density, high porosity, high surface area, and adjustable surface chemistry. Thanks to the latest advances in the synthesis of different types of aerogels, the feasibility of this porous material in several applications has been widely explored. In a variety of high performance applications, aerogels have received much attention as an adsorption medium that removes a variety of environmental and human health pollutants. Although the performance of aerogels in environmental sanitation is encouraging, some shortcomings of aerogels, such as complex drying process, mechanically fragile structure and processing costs, have also been taken into account and have been taken into account been determined in some studies. Degree of relief. This review article aims to describe the synthesis and processing of aerogels and their latest applications in air purification, such as carbon dioxide capture and VOC removal, as well as applications in the treatment of air, water, including oils and toxic organic compounds and heavy metals ion removal.

Recent years have witnessed rise in the production of microbial fermentation of metabolites and proteins for industrial applications. The innovative method aims to improve the conventional batch fermentation and the separation. Furthermore, the idea of downstream processing of the target product enhances the efficiency of the overall process and makes it cost-effective and eco-friendly. Even though being cost-effective and eco-friendly, the process faces challenges in commercial applications. When the concentration of the final product/by-product reaches a certain level, feedback inhibition is a common problem encountered in the fermentation process. Excessive accumulation of end products/by-products in culture also inhibits cell growth and secretion of target metabolites. The fermentation results in the production of antibiotics, fungal metabolites, and amino acids, which come with serious inhibition problems. Hence, to mitigate such problems and enhance fermentation performance, extractive fermentation via in situ ion exchange adsorptive technique can be incorporated. The present review highlights the advances and suggests the strategies to resolve the inhibition problems using extractive fermentation via internal, external, and dispersed resin systems. Furthermore, methods for synthesis of resins are discussed and adsorption mechanism of ion exchanges is also elaborated.

Malaysian oil palm industry produces a significant amount of oil palm residue as solid wastes. These solid wastes are comprised of oil palm residue which contains the stem, fronds from the farms, empty fruit bunch (EFB), mesocarp fibre (MF), and palm kernel shell (PKS) from the oil palm–processing factories. These residues are not successfully reused for other purposes, and the current dumping methods can possibly trigger unfavourable effects to the environment. As oil palm residues are a readily available waste biomass, it has a high potential to be converted into valuable energy-derived products. Hydrothermal carbonization (HTC), which is a thermochemical process, is a method used to treat biomass to produce hydrochar under hot-compressed water. Oil palm residues (palm leaves, palm fronds, and palm shell) were used as the feedstock for producing carbonaceous hydrochar. The key objective of this study is to examine the effect of the reaction temperature, residence time, and acid catalysts on the HTC process. HTC of oil palm residues was optimized at different operating temperatures from 140 to 300 °C and different reaction times between 30 and 240 minutes with a biomass-to-water ratio of 1:10 wt%. Acid catalysts such as citric acid and ascorbic acid were used for the HTC process. The hydrochar produced is further characterized using heating value and elemental and Fourier transform infrared (FTIR) analysis. The yield of hydrochar reduces with the rise of temperature and time but it increases in the presence of acid catalysts. The carbon content of hydrochar is observed to be between 44.36 and 49.50%. The FTIR analysis showed that a high intensity at 1423 cm−1 indicates a high content of lignin and cellulose in the hydrochar. A considerable decrease in the H/C and O/C atomic ratio shows that the dehydration and decarboxylation take place during the HTC process.

Due to the rising demands of cleaner fuels (free from sulfur), most of the oil industries are implementing the process of the desulfurization. In present work, the extractive desulfurization (EDS) efficiency of binary solvents composed as mixtures of bronsted acidic ILs ([Hnmp][HSO4] and [Hnmp][H2PO4]) and nonvolatile organic solvent known as dimethylformamide (DMF), is investigated for the model fuel oil (containing thiophene as S-compounds). The main advantages of using binary solvents are; low viscosity of extractant and reduced cost of the process. Effect of key operating parameters such as temperature, time, multiple steps, initial S-content in oil and oil:binary solvent (w/w) ratio on the S-removal efficiency is examined. Based on the obtained results, optimal 40 °C and 45 min are chosen as operating temperature and extraction time, respectively. Almost 95% of S-removal (decrease from 500 to 22 ppm and 28 ppm) is obtained through five steps extraction for both binary solvents, also these exhibited remarkable extraction performances for different initial S-content of fuel oil. The recyclability and reusability of solvents are investigated, where it is observed that binary solvent has reasonable effectiveness when reused for four times. The solvents can also be regenerated without undergoing any change in the actual structure of ILs. This study shows that EDS based on the binary solvents can be a suitable option to produce the cleaner fuel oils.