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Introduction
Published in D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova, Synthetic Sorbent Materials Based on Metal Sulphides and Oxides, 2020
D.S. Sofronov, K.N. Belikov, M. Rucki, S.N. Lavrynenko, Z. Siemiątkowski, E. Yu. Bryleva, O.M. Odnovolova
Additional issue is concerning green technologies. Intense development of the industry, power engineering, and agriculture continuously increases pollution of the air (Guttinkunda et al. 2019), water (Xie et al. 2020), and soil (Baltas et al. 2020), which have negative impact on human health. Despite the numerous proposed methods of contamination removal, such as filtration, sedimentation, reverse osmosis, chemical deposition, biological treatment, and so on, sorption methods remain one of the most economical effective ones (Jaspal and Malviya 2020). That is why, sorption is often applied in the final stages of wastewater treatment. A variety of the sorption materials are used, both natural, such as clays, minerals, plant materials, or biomaterials, and synthetic ones. The main advantage of the natural sorption materials is relatively low cost, whereas synthetic ones perform much higher sorption capacity. The aforementioned challenges pose some limitations on the production of the sorption materials, which must be greener itself through minimizing the energy consumption and other environment unfriendly factors. Thus, one of the trends in sorbent synthesis leads toward production of the same materials using different methods, with modification of the sorbent characteristics through different synthesis conditions. In this book, to achieve greener technology, the researches were focused on the water solutions without employment of any organic solvents.
Wastewater Reclamation and Reuse Treatment Technology
Published in Donald R. Rowe, Isam Mohammed Abdel-Magid, Handbook of Wastewater Reclamation and Reuse, 2020
Donald R. Rowe, Isam Mohammed Abdel-Magid
Adsorption is a surface phenomenon often used to remove trace levels of contaminants from either a liquid or a gas stream by contact with a solid surface referred to as the adsorbent (e.g., activated carbon, molecular sieves, silica gel, natural soils, etc.). This adsorption phenomenon is influenced not only by the type of adsorbent used but also by the molecular size and polarity of the contaminant, the nature of the solution or gas stream in which the contaminate is dispersed, and the contacting system employed. It is important to be able to relate the amount of contaminant adsorbed from the gas or water stream to the amount of adsorbent needed to reduce the contaminant to an acceptable level. A purely empirical equation often used to describe this adsorption or sorption phenomenon is the Freundlich isotherm.1,5X/M = KC1/n
Integrated Pest Management
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Adsorption. Soil sorption is the affinity a chemical has to adhere to soils. The term “sorption” includes the processes of adsorption and absorption. Adsorption is the binding of a chemical onto the surface of a soil particle while absorption is the binding of a chemical into a soil particle. Adsorption is generally the more important means of binding a chemical to the soil surface. This is greatly influenced by the chemical and physical characteristics of the chemical (e.g., anionic, cationic, or nonionic charges), the soil characteristics or composition, and the nature of the soil solution. The major soil characteristics affecting pesticides are soil texture, permeability, and organic matter content. Coarse, sandy soil textures tend to have low cation exchange capacities (CECs) and high permeability rates; thus, they hold applied materials poorly. Increases in organic matter and certain clays tend to increase a soil’s ability to hold applied materials. This is one reason organic matter should be considered in golf course construction. Clay soils are least likely to allow leaching, but are most likely to have runoff. Most insecticides readily adsorb to soil and thatch, which is why they are rarely detected in groundwater. The majority of fungicides and herbicides are also tightly bound by soil, but some do have the potential to leach to groundwater.
The removal efficiency of lead from contaminated soil: modeling of cations and anions migration during the electrokinetic treatment
Published in Journal of Environmental Science and Health, Part A, 2020
Lead is one of the major environmental pollutants of soil, for that reason, the removal of this metal from soils is important in terms of protection of the environment. Electrokinetic is one of the main procedures for the removal of heavy metals from soils. In the electrolyte system of the soil, electrical current causes electroosmosis, electromigration, and electrophoresis. In the soil two other transport mechanisms, advection and diffusion, exist. Hence, when electrical current is applied to the soil, all five transport mechanisms have to be considered.[1–7] Due to fluid and solute transport through the soil, several geochemical reactions take place within the porous media. These interactions may include diverse processes such as sorption–desorption and precipitation/dissolution behavior during the EK process.[1,8] Sorption refers to the partitioning of contaminants from the solution to the solid phase or soil surface. Sorption mechanisms include surface complexation (i.e., adsorption) or ion exchange. Desorption is the opposite process whereby the contaminants are released from or through a surface.[9]
Kinetics and thermodynamic studies of Cr(VI) adsorption using environmental friendly multifunctional zeolites synthesized from coal fly ash under mild conditions
Published in Chemical Engineering Communications, 2020
Zahra Ghasemi, Iman Sourinejad, Hossein Kazemian, Mojtaba Hadavifar, Sohrab Rohani, Habibollah Younesi
The equilibrium adsorption data of Cr(VI) ions were fitted by the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The Langmuir isotherm is based on the assumption of monolayer sorption of adsorbate molecules on the surface of the adsorbent and is given by the following equation (Ghasemi et al., 2016a): where qe is the equilibrium adsorption capacity of the sorbent in mg g−1 and Ce is the concentration of sorbate ions in mg L−1 at equilibrium. The qm is the maximum capacity of the metal monolayer to be adsorbed in mg g−1, and b is the constant that refers to the bonding energy of adsorption in L mg−1 (Hami Dindar et al., 2015). Nonlinear regression analysis was performed with SigmaPlot software (Sigma Plot 12.0, SPSS Inc., USA) in order to estimate the values of qm and b parameters. In addition, the favorability of Cr(VI) adsorption was controlled by a dimensionless separation parameter RL, based on the following equation (Shahbazi et al., 2011): where b is the Langmuir constant in L mg−1 and C0 the initial metal ions concentration in mg L−1. The value of RL indicates if the type of Langmuir isotherm is irreversible (RL = 0), favorable (0 < RL < 1) or unfavorable (RL > 1).
Cadmium removal by bioclastic granules (Lithothamnium calcareum): batch and fixed-bed column systems sorption studies
Published in Environmental Technology, 2018
Diego Macedo Veneu, Claudio Luiz Schneider, Marisa Bezerra de Mello Monte, Osvaldo Galvão Caldas Cunha, Lídia Yokoyama
Processes such as precipitation, ion exchange, flotation and electrochemical techniques, among others, are generally incapable of meeting legislation requirements regarding the limits for the discharge of metal-containing effluents [4]. These processes generally present several disadvantages, such as incomplete removal, high energy consumption, toxic sludge generation and incorporation of chemicals into the effluent [5,6]. In recent years, as an alternative to these processes, several studies have been conducted using sorption processes. Sorption is defined as the accumulation of a substance or material at an interface between the solid surface and the aqueous solution (dual electric layer). This includes adsorption, absorption or diffusion mechanisms in the solid and precipitation on the surface to form a new adherent solid phase that may consist of chemical species derived from both the aqueous solution and the dissolution of the solid [7,8].