One of the most important issues in today's world is the pollution of water with toxic and dangerous metals. Cadmium is one of the toxic metals that enter the surface and groundwater through various industrial wastewaters. In this paper, polyethylene oxide-based silica monolith was synthesized with a uniform porous structure and was used to remove cadmium ions from the aqueous medium. The chemical and physical properties of silica monolith were characterized by SEM, BET, and FTIR techniques. The results of BET and SEM analysis showed that the monolith has a mesopore structure with a specific surface area of 543 m2g-1. The synthesized silica monolith was used as an adsorbent for cadmium removal in a batch adsorption process and the effects of operating parameters including pH, adsorbent concentration, cadmium initial concentration, and contact time were investigated. The Central Composite Design method was used to optimize the effects of operating parameters. The results of the experimental design showed the importance of pH and adsorbent concentration parameters. The analysis of equilibrium data indicated that the maximum adsorption capacity of the monolith for cadmium is 153 mg g-1. The kinetic data were analyzed with various models and results indicated the importance of chemical adsorption. The results of regeneration and reuse of monolith as an adsorbent showed that the synthesized monolith has a high ability to adsorb heavy metal ions from an aqueous solution and can be an option for water treatment at industrial scale.

Background: In the field of recombinant protein production, downstream processing, especially protein purification, is critical and often the most expensive step. Carbohydrate binding module 64 (CBM64) was shown in 2011 to bind efficiently to a broad range of cellulose materials. Methods: In this study, we developed a protein purification method using nanocrystalline cellulose embedded in a polyacrylamide monolith cryogel and CBM64 affinity tag linked by intein to PD1 as a model protein. The CBM64-Intein-PD1 gene cassette was expressed in E. coli. Following cell lysis, CBM64-Intein-PD1 protein bound to the monolith PA-NCC cryogel. After washing and reducing the pH from 8. 0 to 6. 5, the intein underwent self-cleavage, resulting in the release and elution of pure PD1 protein. Results: The synthesized monolith column had a porous structure with an average pore size of 30 μ, m and a maximum binding capacity of 497 μ, g per gram of dried column. The yield of this purification method was 84%, while the yield of the His tag-acquired CBM64-Intein-PD1 method was 89%. Conclusions: We used cellulose as support for affinity chromatography, which can be used as a costeffective method for protein purification.

In this study, we investigated the selective production of propylene from methanol using monolith-structured ZSM-5 and germanium-modified ZSM-5 nanocatalysts within a fixed-bed reactor system. Optimal reaction conditions were established as 500 °C, 1 bar pressure, and a weight hourly space velocity (WHSV) of 15 h⁻¹, with methanol as the feedstock. To assess the physical and chemical characteristics of the pelletized parent, Ge-modified, and monolith-structured HZSM-5 nanocatalysts, we utilized various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and ammonia temperature-programmed desorption (NH3-TPD). NH3-TPD results indicated a reduction in acidity for the Ge-modified HZSM-5 nanocatalyst, attributed to the partial elimination of strong acid sites. XRD patterns confirmed the presence of the washcoat on the monolith-structured support. Additionally, SEM images of the Ge-modified and monolith-structured HZSM-5 nanocatalysts showed no change in the crystallinity of HZSM-5, while demonstrating a uniform nanocatalyst coating within the channels of the monolith-structured support. The most effective modified nanocatalyst was achieved by incorporating 0.1 wt% germanium into ZSM-5, which resulted in a substantial enhancement of propylene selectivity by 53% and yield by 22.1%. Among the monolith-structured nanocatalysts, variations with single-layer, double-layer, and triple-layer coatings of HZSM-5 were prepared. The single-layer HZSM-5 monolith-coated nanocatalyst exhibited the most significant improvements, with propylene selectivity increasing by 55% and yield by 28.4%. These improvements were attributed to enhanced internal diffusion and reduced mass transfer resistances within the monolith channels, leading to shorter residence times and reduced aromatic formation

The monolithic catalytic converter is still the main pollution control device for modern vehicles in order to reach the ever-increasing legislative demands for low emission standards. The catalytic converters require a large expansion from the exhaust pipe to the front face of the monolith. Unfortunately, packaging constraints often do not permit the use of long diffusers. Hence, flow separation within the diffuser leads to a non-uniform flow distribution across the monolith. A uniform flow distribution at the inlet monolith face is favorable for the conversion efficiency as well as the durability of the catalytic converter. Therefore, the main problem is to optimize the flow distribution at the catalytic converter. It should be noted that due to flow maldistribution in an enlarged inlet of catalytic converter, some parts of the monolith would be non effective. In this research, a new design for inlet diffuser of catalytic converter has been proposed and fabricated. The new inlet diffuser is composed of some tube to tube cones that distribute the flow uniformly at the entrance face of monolith. Temperature, pressure drop, and concentration of pollutants, before and after the catalyst, have been measured. The results show that the new design for inlet diffuser tends to a less uniform temperature field at the entrance of monolith but the flow distribution becomes more uniform. Therefore, an increased conversion efficiency of the catalyst will be obtained.