Sulfur oxide (SO₂) and hydrogen sulfide (H₂S) are considered as one of the major air pollutants in the world today. In addition, high sulfur levels in petroleum distillates can promote the deactivation of catalysts through poisoning in fluidized catalytic cracking (FCC) during hydrocracking of the heavy distillates to lighter ones. The presence of high sulfur-containing compounds in the process streams could cause corrosion of piping and fittings and equipment, thereby damaging the pipelines and leading to air emissions of sulfur-containing compounds, which are undesirable for mankind and his environment. In many cases, a large quantity of SO_x is released into the atmosphere when petroleum distillates that contain substantial amount of sulphur-containing compounds are used as fuel and combust. In this article, a short overview of different desulfurization methods that are employed to remove sulfur from petroleum distillates is provided. In particular, the review concentrates on biodesulfurization technique. In addition, this article intends to provide its readers current status of biodesulfurization (BDS). It critically analyses the trend in the development of the technology to showcase its strength and weakness that could pave a way for future opportunities. Approaches that are suitable to remediate sulfur-contaminated environment are discussed as well. Lastly, speculations on future directions or opportunities that require exploration are provided as a way of provoking the thoughts of researchers in this field.

The improvement of membrane applications for wastewater treatment has been a focal point of research in recent times, with a wide variety of efforts being made to enhance the performance, integrity and environmental friendliness of the existing membrane materials. Cellulose nanocrystals (CNCs) are sustainable nanomaterials derived from microorganisms and plants with promising potential in wastewater treatment. Cellulose nanomaterials offer a satisfactory alternative to other environmentally harmful nanomaterials. However, only a few review articles on this important field are available in the open literature, especially in membrane applications for wastewater treatment. This review briefly highlights the circular economy of waste lignocellulosic biomass and the isolation of CNCs from waste lignocellulosic biomass for membrane applications. The surface chemical functionalization technique for the preparation of CNC-based materials with the desired functional groups and properties is outlined. Recent uses of CNC-based materials in membrane applications for wastewater treatment are presented. In addition, the assessment of the environmental impacts of CNCs, cellulose extraction, the production techniques of cellulose products, cellulose product utilization, and their end-of-life disposal are briefly discussed. Furthermore, the challenges and prospects for the development of CNC from waste biomass for application in wastewater treatment are discussed extensively. Finally, this review unraveled some important perceptions on the prospects of CNC-based materials, especially in membrane applications for the treatment of wastewater.

Recently, the bioconversion of biomass into biofuels and biocommodities has received significant attention. Although green technologies for biofuel and biocommodity production are advancing, the productivity and yield from these techniques are low. Over the past years, various recovery and purification techniques have been developed and successfully employed to improve these technologies. However, these technologies still require improvement regarding the energy-consumption-related costs, low yield and product purity. In the context of sustainable green production, this review presents a broad review of membrane purification technologies/methods for succinic acid, a biocommodity obtained from lignocellulosic biomass. In addition, a short overview of the global market for sustainable green chemistry and circular economy systems or zero waste approach towards a sustainable waste management is presented. Succinic acid, the available feedstocks for its production and its industrial applications are also highlighted. Downstream separation processes of succinic acid and the current studies on different downstream processing techniques are critically reviewed. Furthermore, critical analysis of membrane-based downstream processes of succinic acid production from fermentation broth is highlighted. A short review of the integrated-membrane-based process is discussed, as well, because integrating “one-pot” lignocellulosic bioconversion to succinic acid with downstream separation processing is considered a critical issue to address. In conclusion, speculations on outlook are suggested.

In this study, adsorption performance of pomegranate leaf powder (PLP) for the removal of dibenzothiophene (DBT) from petroleum distillates is presented. Morphology and elemental composition, surface chemistry, and textural property of the PLP were checked using scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and N₂ physi-sorption at 77 K, respectively. Model oil contained 0.1 g DBT in 100 mL hexane was used for the performance evaluation and conducted in batch mode. The results show DBT removal of 70.55%, with the adsorbent retaining about 97.81% of its capacity after fourth cycle of usage. Results from SEM-EDX and FTIR indicate that DBT was adsorbed on the surface of PLP. Adsorption isotherm data fitted onto Freundlich and Langmuir isotherms models show very good coefficient of determination (R²) values of 0.9952 (for Langmuir) and 0.9979 (for Freundlich), indicating suitability of the models to describe the process. The adsorption kinetics of DBT onto PLP follows pseudo-second-order kinetics and the experimental q_e (53.66 mg/g) values obtained is very close to the model-estimated value q_e (55.55 mg/g). The negative value of ΔG^o and the positive values of ΔH^o obtained in the thermodynamic studies indicate that adsorption of DBT onto the PLP is an endothermic and spontaneous process at the temperatures studied.