Keywords: adsorption isotherm

SORPTION PROPERTIES OF BLACK SOLDIER FLY (HERMETIA ILLUCENS) MAGGOTS VERMICULTURING ZOOCOMPOST TO «METHYL ORANGE» DYE

Abstract
The paper considers the issues, concerned with possible release as part of sewage waters of an organo-mineral pollutant ‒ methyl orange dye – to the environment. This dye has become widely used in textile industry, food industry, and in building materials production. High concentrations of this dyestuff are toxic and can cause damage to skin and eyes. Getting into the body system, the dye can form even more toxic aromatic amines in course of metabolic processes. The toxic effect can occur even at 5% concentration of the dye.
To reduce the toxic influence of wastewaters, containing dyestuffs such as methyl orange, various purification methods are used, including sorption. To increase the cost-effectiveness of the process, the sorbents, based of various industrial wastes, have found application lately. In the present research the material, based on black soldier fly (Hermetia Illucens) maggots’ vermiculture, was used.
According to experimental findings and the adsorption isotherm, the type of the sorption material’s pores and the type of sorption were determined. It has been demonstrated that the sorption material belongs to transition-porous sorbents, which is essential for extracting large molecules of the dye. According to the isotherm, the dye molecules sorption proceeds in stages: at first, a monolayer is formed, which is indicated by the first plateau in the isotherm. At the second stage, a multilayer in the form of dye molecules’ chains or clusters – the second plateau in the isotherm – is formed. The sorption mechanism is predetermined by the specific composition of zoocompost particles. Zoocompost is rich in humic compounds with such functional groups as ‒NH, ‒OH, ‒C=O. The presence of these groups makes it possible to adsorb anionic dyes, including methyl orange dye, due to electrostatic interactions or hydrogen bonding.
The influence of the sorbent’s weight, particles size, reaction mix temperature, duration of sorption process on methyl orange dye removal degree was studied. The sufficient efficiency of the process up to 90% was demonstrated.
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THE USAGE OF VEGETABLE SORBENT FOR REMOVING CONGO RED DYE FROM TEST SOLUTIONS

Abstract
The research findings of sorption purification of test water environment, containing Congo red dye, by using this crop farming waste as a sorption material have indicated that the maximum sorption capacity of its biomass amounts to 0.37 mmol/g. The electronic microscopy data and the research findings of physical-chemical and sorp-tion properties of a new vegetable sorption material, obtained from sunflower (Heliánthus ánnuus) stalks, are presented. The processing of the data demonstrated that the obtained adsorption isotherm of Congo red belongs to Type V isotherms according to classification by Brunauer-Deming-Deming-Teller (BDDT) or to the S-type, according to Giles’ classification. With that, adsorption process is the most accurately described by the Freundlich model, and the process proceeds on the heterogeneous surface of the sorption material.
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