▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

Mitigation and Adaptation Strategies for Global Change

The ubiquitous presence of contaminants in water poses a major threat to the safety of ecosystems and human health, and so more materials or technologies are urgently needed to eliminate pollutants. Polymer materials have shown significant advantages over most other adsorption materials in the decontamination of wastewater by virtue of their relatively high adsorption capacity and fast adsorption rate. In recent years, “green development” has become the focus of global attention, and the environmental friendliness of materials themselves has been concerned. Therefore, natural polymers-derived materials are favored in the purification of wastewater due to their unique advantages of being renewable, low cost and environmentally friendly. Among them, natural plant gums show great potential in the synthesis of environmentally friendly polymer adsorption materials due to their rich sources, diverse structures and properties, as well as their renewable, non-toxic and biocompatible advantages. Natural plant gums can be easily modified by facile derivatization or a graft polymerization reaction to enhance the inherent properties or introduce new functions, thus obtaining new adsorption materials for the efficient purification of wastewater. This paper summarized the research progress on the fabrication of various gums-based adsorbents and their application in the decontamination of different types of pollutants. The general synthesis mechanism of gums-based adsorbents, and the adsorption mechanism of the adsorbent for different types of pollutants were also discussed. This paper was aimed at providing a reference for the design and development of more cost-effective and environmentally friendly water purification materials.

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Green and Superior Adsorbents Derived from Natural Plant Gums for Removal of Contaminants: A Review

The regeneration energy consumption Q_(str),in membrane-based absorption of flue gas CO_2,is being analyzed in detail and a general calculation formula is derived,which is a function of three factors,i.e.the membrane contactor's performance factor,the solvent's property factor and the heat exchanger's performance factor.The possibility of reducing Qstr is discussed by making use of the general regeneration energy consumption calculation formula with given performance factors of the membrane contactor.Results indicate that Qstr can effectively be reduced,by increasing the solvent's mass concentration φ,as long as the limiting φ_(max) is not being surpassed;Q_(str) can also effectively be reduced by proper blending the absorbent. Raising the regeneration degree ξ of the enriched absorbent helps to reduce Q_(str),but only to a certain extent,otherwise Q_(str) will tend to increase again.By improving the performance of the lean-rich solvent's heat exchanger,can Q_(str) also be reduced to a certain extent;but this may entail an increase of investment and therefore a heat exchanger should be opted with proper property,optimized by counterposing investment to Q_(str).

An Analysis of Regeneration Energy Consumption in Absorption and Dissociation Processes of Flue Gas CO_2 and its Simulation

The regularities of carbonation in the process of CO2 capture were investigated using ammonia solution by laboratory-scale and bench-scale device. The research showed that the lower volatility of NH3 and higher rate of carbonization in solution could be achieved with ammonia concentration ranging from 10 to 16 wt%. The emission of ammonia accelerated with the increasing of flow of flue gas, and the bubbling function of air was apparent in a lower CO2 volume fraction, which has an adverse effect on carbonation of solution. Benefits of environment and economic could be achieved in CO2 capture using ammonia solution so long as appropriate ammonia concentration, the flue gas flow and volume fraction of CO2 were determined.

Experimental Study on Regularities of Carbonation for CO2 Capture Using Ammonia Solution

Low-concentration organic dye wastewater severely threatens the growth and reproduction of animals and plants, as well as the survival and development of human beings and the environment. Although versatile hydrogel composites have been prepared owing to their excellent adsorption performance, the high-removal efficiency and fast adsorption rate are still two crucial problems related to practical applications. Herein, xanthan gum-g-poly (acrylic acid-co-acrylamide)/biochar composite hydrogels with high-removal efficiency and fast adsorption rate of methylene blue (MB) are synthesized using sodium dodecyl sulfate as a pore-foaming agent. The composite hydrogels exhibit rough and porous three-dimensional structures, which can make the internal active adsorption sites to be fully exposed and facilitate the MB diffusion process. MB's removal efficiency can reach 96.64% within 30 minutes, which is almost the first time that a biochar-contained hydrogel could show superior removal efficiency of more than 95% in such a short adsorption time. The factors affecting the adsorption performance are studied comprehensively. Langmuir and pseudo-second-order models fit the adsorption process well. Moreover, the MB removal rate still exceeds 80% after eight cycles, which is also a vital indicator for practical treatment. Adsorption mechanism analysis shows that the synergistic effect among biochar, xanthan gum, and polymer chains and the porous structure improve the adsorption performance of the composite hydrogels. The proposed hydrogel-biochar composites with high-removal efficiency and adsorption rate are highly promising as an alternative adsorbent for advanced printing and dyeing wastewater treatment. 

Hydrogel‐biochar composites for removal of methylene blue: Adsorption performance, characterization, and adsorption isotherm, kinetics, thermodynamics analysis

Xiang Peng Wang

Papers

Experimental Study on Regularities of Carbonation for CO2 Capture Using Ammonia Solution

Hydrogel‐biochar composites for removal of methylene blue: Adsorption performance, characterization, and adsorption isotherm, kinetics, thermodynamics analysis

Formation and Flow Characteristics of Methane Hydrates in High-Pressure Pipelines

Porous biochar composite hydrogel for effective removal of low-concentration methylene blue from wastewater