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Journal ArticleDOI

Cr(VI) adsorption by a green adsorbent walnut shell: Adsorption studies, regeneration studies, scale-up design and economic feasibility

TL;DR: In this paper, a scale-up design for Cr(VI) removal using walnut shell as an adsorbent and its economic feasibility are done to find out its applicability in real life.
About: This article is published in Process Safety and Environmental Protection.The article was published on 2018-05-01. It has received 90 citations till now. The article focuses on the topics: Adsorption & Langmuir adsorption model.
Citations
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Journal ArticleDOI
TL;DR: In this article, the adsorption of congo red and methylene blue dyes in aqueous solution were characterized via XRD, FTIR and SEM techniques and the dye isotherms at three temperatures were quantified.

287 citations

Journal ArticleDOI
TL;DR: Results from the filtration experiments indicate a substantial variation in the feed volume that the membrane can treat before the permeate lead concentration reaches the allowable limit of 10 ppb, depending on the process parameter.

182 citations

Journal ArticleDOI
TL;DR: In this paper, a detailed analysis of the current situation and the development of devices required for each link in the preliminary processing of walnut is discussed, and the working mechanism of each link type and its influence on the design of a corresponding device are summarized.
Abstract: The walnut varieties in China are rich, the planting area in the country is wide, and the yield ranks at the forefront of the world Walnut kernel is the most important application part of the walnut fruit An in-depth study found that the by-products of walnut, such as green husk and walnut shell, also have great application potential and are cheap raw materials for the extraction of important medical ingredients and the production of industrial products However, the by-products are often burned or discarded as waste during processing, which not only wastes resources but also causes environmental pollution To realize the high value-added application of the walnut fruit, a deep processing of each part of the walnut should be considered Preliminary processing is the key link before walnuts enter the field of intensive processing and consumption The advanced level of the required technological equipment can help to determine the quality of the walnut products The preliminary processing of walnuts in China is mainly divided into six steps: green husk removal, walnut drying, walnut size classification, walnut shell-breaking, walnut shell–kernel separation, and walnut kernel skin removal This paper starts with a presentation of the importance of each link and the existing bottleneck Then, the paper systematically discusses the analysis of the current situation and the development of devices required for each link The working mechanism of each link type and its influence on the design of a corresponding device are summarized On the basis of the corresponding working mechanism, this study classifies and summarizes the characteristics of the core mechanism of the devices for each preliminary process link; then, it evaluates and analyzes the existing typical mechanical devices according to their types Finally, the influence rule of the various devices for each link in the preliminary processing is analyzed as a means of ensuring high-quality walnuts

79 citations

Journal ArticleDOI
Lili Ren1, Xu Jian1, Yuchen Zhang1, Jiang Zhou1, Donghui Chen1, Chang Zhiyong1 
TL;DR: Porous chitosan microspheres provided adsorption sites of the amino and hydroxyl groups for the removal of Cr(VI) in detailed analysis of scanning electron microscopy, porosity and Fourier transform infrared spectra.

76 citations

Journal ArticleDOI
TL;DR: In this article, the authors applied a sludge conditioning process involving calcium hypochlorite (Ca(ClO)2) oxidation, ferric coagulant re-flocculation, and walnut shell skeleton construction to remove extracellular polymeric substances (EPS) and bound water in sludge.

74 citations


Cites background from "Cr(VI) adsorption by a green adsorb..."

  • ...[36] investigated the use of WS as a green adsorbent to remove Cr(VI) in a continuous fixed bed adsorption column....

    [...]

  • ...WS is a type of biomass that has sparked significant research attention in recent years [35,36]....

    [...]

References
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Journal ArticleDOI
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

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TL;DR: A new theoretical model addressing the adsorption and breakthrough of contaminant vapors or gases with respect to solid sorbents is developed, less complicated and easier to apply to practical industrial hygiene problems than theories developed previously.
Abstract: Using the principles of gas adsorption kinetics, we have developed a new theoretical model addressing the adsorption and breakthrough of contaminant vapors or gases with respect to solid sorbents. Specifically, we have applied the theory to predict respirator cartridge service life in connection with individual contaminant exposure to toluene, vinyl chloride, ethyl acetate, and each of several different trichlorinated hydrocarbons at several levels of concentration. Theoretical expressions and contaminant breakthrough curves derived from our new approach are compared with those published previously by Mecklenburg and by Wheeler. The breakthrough curves derived by Mecklenburg and by Wheeler have approximately the same shape as the corresponding experimental curves for 0% to 40% breakthrough. However, these curves deviate in varying degrees from the experimental data at breakthrough values exceeding 40%. By contrast, our new theory agrees with published experimental results over the entire range of 0% to 10...

916 citations

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TL;DR: A continuous fixed bed study was carried out by using Mowital®B30H resin immobilized dried activated sludge as a biosorbent for the removal of phenol from aqueous solution.

888 citations

Journal ArticleDOI
TL;DR: In this article, the effects of pH, contact time, initial concentration of adsorbate and temperature on adsorption of activated carbon were investigated, and the results showed that both Langmuir and Freundlich models fitted the data reasonably but the Langmuirusorption isotherm model fitted better in the temperature range studied.

609 citations