Regenerable adsorbent for removing ammonia evolved from anaerobic reaction of animal urine

The waste gas evolved from biodegradation of animal urine contains ammonia causing environmental concerns. A new and effective method for removing ammonia from such waste gas using reactive adsorption is presented. In the process, activated carbon impregnated with H2SO4（H2SO4/C） is employed. Ammonia in the waste gas reacts with H2SO4 on the adsorbent instantaneously and completely to form （NIL）2SO4. The H2SO4/C adsorbent is high in NH3 adsorption capacity and regenerable. The NH3 removal capacity of this regenerable adsorbent is more than 30 times that of the adsorbents used normally in the industry. The spent H2SO4/C is regenerated by flowing low-pressure steam through the adsorbent bed to remove the （NH4）2SO4 from the adsorbent. The regeneration by-product is concentrated （NH4）2SO4 solution, which is a perfect liquid fertilizer for local use. Re-soaking the activated carbon with H2SO4 solution rejuvenates the activity of the adsorbent. Thus the H2SOJC can be reused repeatedly. In the mechanism of this reactive adsorption process, trace of H20 in the waste gas is a required, which lends itself to treating ammonia gas saturated with moisture from biodegradation of animal urine.

Desulfurization using the 1,2-dimethylimidazolium ionic liquid as an adsorbent

The aim of this study is to investigate the possible use of a 1,2-dimethylimidazolium ionic liquid,2,2-bis（（1,2-dimethylimidazolium）methyl）propane-1,3-diol hexafluorophosphate（1）,as an adsorbent to selectively remove aromatic heterocyclic sulfur compounds from model fuels.The result indicates that adsorbent 1 is insoluble in model fuels.The spent IL saturated sulfur compounds could be regenerated by a water dilution process.The influence of extraction time or temperature as well as the molar ratio of 1 to aromatic heterocyclic sulfur compound was also studied.

Investigation of adsorption/desorption performance by aminopropyltriethoxysilane grafted onto different mesoporous silica for post-combustion CO_(2) capture

Mesoporous silicas with hexagonal structure(MCM-41 and SBA-15)and cubical interconnected pore structure(KIT-6)were synthesized and modified with aminopropyltriethoxysilane(APTES)for using as adsorbents in carbon-dioxide(CO_(2))-adsorption application.The CO_(2)-adsorption experiment was carried out at room temperature and atmospheric pressure using 15%CO_(2) with a flow rate of 20 mL/min and the desorption experiment was carried out at 100℃ under N_(2) balance with a flow rate of 20 mL/min.The adsorption capacity and adsorption rate of all modified mesoporous silicas were enhanced due to the presence of primary amine in the structure,which was able to form a fast chemical reaction with CO_(2).All adsorbents showed good adsorption performance stability after using over five adsorption/desorption cycles.Due to the effect of the adsorbents’porous structure on the adsorption/desorption process,an adsorbent with sufficient pore-size diameter and pore volume together with interconnected pore,KIT-6,represents a promising adsorbent that gave the optimum adsorption/desorption performance among others.It showed reasonable adsorption capacity with a high rate of adsorption.In addition,it could also be regenerated with 99.72% efficiency using 12.07 kJ/mmol CO_(2) of heat duty for regeneration.

Recent progress of arsenic adsorption on TiO2 in the presence of coexisting ions： A review

Arsenic（As）-contaminated wastewater and groundwater pose a pressing environmental issue and worldwide concern. Adsorption of As using TiO_2materials, in combination with filtration,introduces a promising technology for the treatment of As-contaminated water. This review presents an overview on the recent progress of the application of TiO_2for removal of As from wastewater and groundwater. The main focus is on the following three pressing issues that limit the field applications of TiO_2for As removal： coexisting ions, simulation of breakthrough curves, and regeneration and reuse of spent TiO_2materials. We first examined how the coexisting ions in water, especially high concentrations of cations in industrial wastewater,affect the efficacy of As removal using the TiO_2materials. We then discussed As breakthrough curves and the effect of compounded ions on the breakthrough curves. We successfully simulated the breakthrough curves by PHREEQC after integrating the CD-MUSIC model. We further discussed challenges facing the regeneration and reuse of TiO_2media for practical applications. We offer our perspectives on remaining issues and future research needs.