Mistakes and inconsistencies regarding adsorption of contaminants from aqueous solutions: A critical review.
TL;DR: The inaccurate use of technical terms, the problem associated with quantities for measuring adsorption performance, the important roles of the adsorbate and adsorbent pKa, and mistakes related to the study of adsor adaptation kinetics, isotherms, and thermodynamics are discussed.
About: This article is published in Water Research.The article was published on 2017-09-01. It has received 1691 citations till now.
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TL;DR: Criteria for choosing the optimum isotherm model is established through a critical review of different adsorption models and the use of various mathematically error functions such as linear regression analysis, nonlinear regressionAnalysis, and error functions for adsorption data optimization.
1,151 citations
TL;DR: In this article, the Van't Hoff equation is used in different manners without any criteria about the concepts of physical-chemistry of equilibrium for calculation of thermodynamic parameters of adsorption.
999 citations
TL;DR: In this article, the authors provide a systematic and comprehensive overview of the researches conducted from 2005 to 2018 for removing uranium from aqueous solution by these emerging materials, including inorganic materials (e.g., clay minerals, metal oxides, mesoporous silica), organic polymers, carbon family materials, and porous framework materials.
337 citations
TL;DR: In this article, the authors provided an up-to-date information on the application of sustainable low-cost alternative adsorbents such as agricultural solid wastes, agricultural by-products, and biomass-based cost-effective activated carbon and various other natural materials in the batch adsorptive removal of heavy metal and dye from aqueous phase.
Abstract: Agricultural solid wastes either in natural or in modified forms have been successfully used for decades as non-conventional cost-effective adsorbents for removing metal ions and dyes from their aqueous phase and have been recognized as a sustainable solution for wastewater treatment. Therefore, this review article provides extensive literature information about heavy metals and dyes, their classifications and toxicity, various treatment methods with emphasis on adsorption characteristics by numerous agricultural solid wastes, or agricultural solid waste-derived adsorbents under various physicochemical process conditions. This review article not only provided an up-to-date information on the application of sustainable low-cost alternative adsorbents such as agricultural solid wastes, agricultural by-products, and biomass-based cost-effective activated carbon and various other natural materials in the batch adsorptive removal of heavy metal and dye from aqueous phase but also presented a comprehensive compilation of adsorptive pollutant removal information based on various reported continuous column operation studies which is one of the new aspect to this review article. The effectiveness of various batch and column operational process parameters on mechanistic adsorptive removal of both heavy metals and dyes by various agricultural solid waste-based adsorbents has been critically discussed here. Batch and column adsorption mechanism, batch kinetics, column dynamic modeling, and adsorptive behavior of adsorbents under various process parameters have also been critically analyzed and compared. Finally, literature information on recovery and regeneration through desorption techniques and cost comparison of various agricultural solid waste adsorbents with commercial activated carbons have also been reported here. Conclusions have been drawn from the literature reviewed, and few suggestions for future research direction are proposed.
332 citations
Cites background from "Mistakes and inconsistencies regard..."
...According to Freundlich theory, the adsorption isotherm becomes linear when n = 1, favorable when n < 1, and unfavorable when n > 1 (Tran et al. 2017)....
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...KF (mg g−1)/(mg L−1)n is the Freundlich constant and n is the dimensionless Freundlich intensity parameter, indicating the magnitude of the adsorption driving force or the surface heterogeneity (Tran et al. 2017)....
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TL;DR: An overview of water pollution by these pollutants, as well as a review of the recent literature about the use of low-cost adsorbents for the removal of the main pharmaceuticals found in surface water, focusing on municipal and agroindustrial wastes as precursors are presented.
312 citations
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TL;DR: In this article, the absorption index at the wave length of the band maximum was found to be proportional to the total concentration of metal at shorter wave lengths, however, deviations were observed, the absorption increasing more rapidly with concentration than Beers' law would demand.
Abstract: solutions investigated, the absorption index diminishing approximately 1% for a rise in temperature of one degree. 6. In liquid ammonia rough measurements of concentration showed the absorption index to be proportional to the total concentration of metal. 7. In methylamine the absorption index, at the wave length of the band maximum is also proportional to the total concentration of metal. At shorter wave lengths, however, deviations were observed, the absorption increasing more rapidly with concentration than Beers’ law would demand. The ratio of the absorption index a t 650pp to that a t 53opp increases not only with increasing concentration of the metal but also with increasing concentration of the reaction product of the metal with methylamine, and probably also with increasing temperature. 8. These observations can be accounted for by the following hypotheses: The color in all cases is due to electrons combined with the solvent. In ammonia the dissociation of the metal into electrons is nearly complete, and the concentration of electrons uncombine4 with solvent is negligible compared with that of the solvated electrons. In other words, the solvation of the electrons is nearly complete. In methylamine, on the other hand, the concentration of un-ionized metal is no longer negligible and is responsible for the increased absorption a t the shorter wave lengths. The solvation of the electrons in methylamine is incomplete and diminishes as the temperature is increased.
18,573 citations
TL;DR: In this paper, it was shown that the rate of adsorption of persistent organic compounds on granular carbon is quite low and the rate is partially a function of the pore size distribution of the adsorbent, of the molecular size and configuration of the solute, and of the relative electrokinetic properties of adsorbate and adsorbents.
Abstract: Laboratory investigations show that rates of adsorption of persistent organic compounds on granular carbon are quite low. Intraparticle diffusion of solute appears to control the rate of uptake, thus the rate is partially a function of the pore size distribution of the adsorbent, of the molecular size and configuration of the solute, and of the relative electrokinetic properties of adsorbate and adsorbent. Systemic factors such as temperature and pH will influence the rates of adsorption; rates increase with increasing temperature and decrease with increasing pH. The effect of initial concentration of solute is of considerable significance, the rate of uptake being a linear function of the square-root of concentration within the range of experimentation. Relative reaction rates also vary reciprocally with the square of the diameter of individual carbon particle for a given weight of carbon. Based on the findings of the research, fluidized-bed operation is suggested as an efficient means of using adsorption for treatment of waters and waste waters.
7,115 citations
6,913 citations
TL;DR: In this paper, the authors present a review of the state-of-the-art in isotherm modeling, its fundamental characteristics and mathematical derivations, as well as the key advance of the error functions, its utilization principles together with the comparisons of linearized and nonlinearized isotherms models have been highlighted and discussed.
5,914 citations