Recovering Nutrients from Waste Black Water Through Multi-Functional Mesoporous Silica

In order to prevent the harmful effects in water phase such as eutrophication, industrial and urban sewages must be treated before discharging into the aquatic environment. In this work, amine grafted magnetic nanoporous silica materials are synthesized and applied as an adsorbent for the recovery of nutrients from waste black water. The magnetic force could separate the surface func-tionalized nanoporous silica materials from aqueous medium after treatment, and showed the higher adsorption capacity of nutrients than that of the original mesoporous silica. The multi-functional nanoporous silica adsorbents were effectively removed phosphate and nitrate at 20 °C with the maximum adsorption capacities of 42.5 and 34.9 mg/g, respectively. The overall results indicated that the synthesized multi-functional nanoporous silica sorbents can be a candidate material for the nutrient recovery in wastewater treatment system.

Radiation synthesis of imidazolium-based ionic liquids modified silica adsorbents for ReO4- adsorption

The selective elimination of radioactive TcO4- from radioactive wastes is becoming increasingly critical for environmental security. In this work, a series of novel adsorbents (Si-IL-X, X= NO3, Cl, BF4, NTf2)...

Zeolite for Potential Toxic Metal Uptake from Contaminated Soil: A Brief Review

Soil pollution is an increasingly urgent problem for the global environment. Soil can be contaminated with potential toxic metals from many anthropogenic activities, besides fossil fuel combustion and crude oil production, ranging from industry to mining and agriculture. Many technologies have been analysed to solve this type of environmental pollution and methods involving the use of minerals (e.g., clay minerals, zeolites, and natural silica adsorbents) are widely described in the literature. This article provides a summary of studies concerning the use of zeolites in soil remediation. A considerable number of these experiments were conducted using natural zeolites, while fewer concerned the utilization of synthetic zeolites. The mechanism controlling the successful application of these minerals was analysed through referring to global data published on this topic over the last few decades. This review also briefly discusses the limitations on zeolite applications and the drawbacks of the approaches analysed.

Evaluation on the Stability of Amine-Mesoporous Silica Adsorbents used for CO2 Capture

Amine-mesoporous silica has been considered as a promising CO2 adsorbent with high potential for the reduction of energy consumption and CO2 capture cost; however, its stability could greatly vary with synthetic method. In this study, adsorbents prepared by impregnating different amines including polyethylenimine (PEI) and 3-aminopropyltriethoxysilane (APTES) onto mesoporous silica were used to evaluate the effect of amines selection on the stability of adsorbents used in CO2 capture process. Results revealed that APTES impregnated mesoporous silica (APTES-MPS) is more stable than PEI-impregnated mesoporous silica (PEI-MPS); APTES-MPS was thermally decomposed at ≈280 oC, while PEI-MPS was thermally decomposed at ≈180 oC only. PEI-MPS was particularly less stable when operating under dry condition; its CO2 adsorption capacity reduced by 22.1% after 10 adsorption/regeneration cycles, however, the capacity can be significantly improved in humid condition. APTES-MPS showed a greater stability with no significant reduction in CO2 capture capacity after 10 adsorption/regeneration cycles. In general, APTES-MPS adsorbent possesses a higher stability compared to PEI-MPS thanks to the formation of chemical bonds between amino-functional groups and mesoporous silica substrate. Keywords: Mesoporous silica; CO2 capture; Adsorption; Regeneration; Emission.

Siliceous foam material and its application in post-combustion carbon capture for NGCC plants: effects of aging conditions

In an effort to reduce the overall energy penalty and capital expenditure associated with carbon capture technologies, a variety of porous solid adsorbents have been developed. The limitations of solid sorbent in large-scale process are related to its CO2 uptake, physicochemical stability, lifecycle, regenerability and operation condition. In this paper, siliceous foam materials were synthesized via a modified microemulsion templating method and functionalized with branched polyethylenimine (PEI). The physical characteristics of synthesized silica adsorbents under different aging conditions were analysed via N2 sorption analysis and Scanned Electron Microscopy (SEM) morphological analysis. CO2 uptake was evaluated by thermogravimetric analyser (TGA). The results show that CO2 uptake is desirable even under low CO2 partial pressure and is predictable with multiple linear regression (MLR) model in the range of examined materials.