Modeling and Experimental Investigation of Sulfurous Compounds Removal from Gas Condensate through Ultrasound-Assisted Oxidative Desulfurization Method.

This study employed an ultrasound-assisted oxidative desulfurization process (UAOD) to investigate the degradation of three sulfurous compounds in the synthetic gas condensate. Various parameters, including oxidizers (hydrogen peroxide, sodium peroxide, potassium superoxide), promoters (formic acid, acetic acid), catalysts (phosphotungstic acid, ferrous(II) sulfate, zirconium dioxide, vanadium pentoxide, aluminum oxide γ, copper(II) oxide), and phase transfer agents (isobutanol, tetraoctylammonium bromide, and tetra-n-butylammonium fluoride), were examined to identify the optimal combination for reducing sulfurous compounds in the UAOD process. The influence of the extraction stage and reactor vessel material on the desulfurization efficiency was also investigated. Results revealed that hydrogen peroxide, formic acid, phosphotungstic acid, and isobutyl alcohol were the most effective oxidizers, promoters, catalysts, and phase transfer agents, respectively. Response surface methodology was used to determine the optimal conditions by evaluating different concentrations of these reagents within specific ranges. The study considered ranges such as 10-70 vol % of hydrogen peroxide, 5-70 vol % of formic acid, 1-30 wt % of phosphotungstic acid, 1-30 vol % of isobutanol, and 5-40 min of ultrasonic ripple time. Empirical models were developed for each sulfurous compound type, providing optimal conditions for sulfur removal with an error margin of less than 0.1%. The validity of the suggested models was confirmed through an industrial data analysis. Additionally, it was observed that increasing the number of extraction stages improved desulfurization efficiency, and using a stainless-steel reactor vessel was more suitable than using a glass vessel.

A review of the application of fungi as an effective and attractive bio-adsorbent for biosorption of heavy metals from wastewater.

One of the most hazardous environmental pollutants is the pollution risen by heavy metal ions in effluents, which is increasing due to the increasing human activity and the development of urbanization. Notwithstanding the economic challenges to control the pollution of effluent treatment processes, it seems necessary to provide effective approaches. The sorption method is widely used due to low-cost, flexibility in design and operation, repeatability, and significant performance. Hence, the need for more environmentally friendly sorbents to eliminate metal ions is greater than ever. Due to the unique features such as the presence of chitin and chitosan in the cell wall, high absorption capacity, environmental friendliness, availability, and cheapness, the use of fungi as adsorbent has received much attention. Therefore, this work tries to address the use of fungi as biosorbents to remove these metals, the dangers of heavy metals, and their sources. Moreover, equilibrium, kinetic, and thermodynamic behaviors of the heavy metal ion adsorption process in the literature are briefly studied.

A review of the application of sea material shells as low cost and effective bio-adsorbent for removal of heavy metals from wastewater.

The pollution caused by heavy metal ions in industrial wastewater is of a great concern. Applying effective and low-cost methods is an urgent need for treatment of polluted water and aqueous solutions. Biosorption have received the most attention among the various methods. It has become an alternative technique to conventional technologies due to low cost, simple operation and treatment for heavy metal recovery, and high selectivity. In recent years, sea material shells have been applied as one of the most cost-effective bio-adsorbents due to their special properties. They are environmentally friendly, low cost, and easy to access and have high adsorption capacity. The purpose of this review is to present the application of oyster shell, snail shell, and shrimp shell as low-cost and effective biosorbents for removal of noxious heavy metals from aqueous solutions. In addition, heavy metals, their sources, and ways to remediate them from waste streams and various factors affecting the biosorption process with sea materials shells are also reviewed. Moreover, a brief description and literature review of the equilibrium, kinetic, and thermodynamic behaviors of the heavy metal ion adsorption process on sea material shells have been studied. Finally, further applications of sea materials shell for waste effluents treatment are specially focused.