Kinetic and equilibrium study of the removal of reactive dye using modified walnut shell

AN EFFECTIVE BIOSORBENT DERIVED N EFFECTIVE BIOSORBENT DERIVED FROM PRODUCTION WASTE ROM PRODUCTION WASTE FOR WATER TREATMENT: STUDYING OR WATER TREATMENT: STUDYING THE ADSORPTION OF SYNTHETIC DYES HE ADSORPTION OF SYNTHETIC DYES

Introduction. Eco-friendly disposal of food waste, in particular, nutshells and fruit kernels, is an important issue to ensure sustainable nature management. These secondary raw materials are the source of valuable polymeric materials, cellulose and lignin.Problem Statement. IGiven the capacity of the food industry in Ukraine and the amount of waste produced, the development of technologies for processing lignin-cellulose biomass is an important research and practical issue.Purpose. The purpose of this research is to study the adsorption properties of chemically modified biosorbent based on plant materials concerning synthetic dyes of different types and classes; to assess the feasibility of biosorbent production and efficiency of its application in water treatment.Materials and Methods. Lignocellulose sorbent (LCS) has been synthesized from non-wood raw materials by chemical modification with the use of phosphoric acid with the addition of urea in an aqueous media. The Fourier transform infrared and standard methods of plant raw material analysis have been used to determine the physicochemical characteristics of LCS. The adsorption of anionic (methyl orange, alizarin red S, eosin Y), cationic (methylene blue, neutral red), and nonionic (aniline yellow) dyes on LCS from aqueous solution has been studied in the batch mode.Results. The adsorption capacity of LCS towards cationic dyes (47.0–53.3 mg/g) is higher than that of anionic (22.2–36.9 mg/g) and nonionic (4.7 mg/g) ones. The adsorption kinetics have been adequately described by a pseudo-second-order equation. Adsorption of all classes of dyes on LCS is thermodynamically feasible, spontaneous, and endothermic process. The liquid by-product of LCS production contains 15% nitrogen and 10% phosphorus, so it may be used as a fertilizer. Conclusions. The proposed method for processing food waste provides obtaining effective sorbent and liquid NP-fertilizer. LCS removes both cationic and anionic pollutants from water, so it may be considered a promisingbiosorbent for water purification.

Factors Affecting Synthetic Dye Adsorption; Desorption Studies: A Review of Results from the Last Five Years (2017-2021)

The primary, most obvious parameter indicating water quality is the color of the water. Not only can it be aesthetically disturbing, but it can also be an indicator of contamination. Clean, high-quality water is a valuable, essential asset. Of the available technologies for removing dyes, adsorption is the most used method due to its ease of use, cost-effectiveness, and high efficiency. The adsorption process is influenced by several parameters, which are the basis of all laboratories researching the optimum conditions. The main objective of this review is to provide up-to-date information on the most studied influencing factors. The effects of initial dye concentration, pH, adsorbent dosage, particle size and temperature are illustrated through examples from the last five years (2017-2021) of research. Moreover, general trends are drawn based on these findings. The removal time ranged from 5 min to 36 h (E = 100% was achieved within 5-60 min). In addition, nearly 80% efficiency can be achieved with just 0.05 g of adsorbent. It is important to reduce adsorbent particle size (with Φ decrease E = 8-99%). Among the dyes analyzed in this paper, Methylene Blue, Congo Red, Malachite Green, Crystal Violet were the most frequently studied. Our conclusions are based on previously published literature.

Polyethyleneimine-impregnated alkali treated waste bamboo powder for effective dye removal

In this study, the polyethyleneimine (PEI) modified waste bamboo powder (WBP-Na-PEI) was successfully prepared and applied to adsorbing Congo red (CR) dye from aqueous solution. The obtained materials were characterized by field emission scanning electron microscope, X-ray diffraction, Fourier transform-infrared, and thermogravimetric analysis. The results showed that WBP-Na-PEI(1.8 K-5) was synthesized successfully and PEI uniformly covered the WBP-Na-PEI(1.8 K-5) surface. In the process of adsorption, four kinds of influencing factors were discussed, and the adsorption mechanisms such as kinetics, isotherm, thermodynamics were explored. The maximum adsorption capacity of WBP-Na-PEI(1.8 K-5) was 992.94 mg·g^-1 at 298 ± 1 K, and the removal efficiency was over 98%. Pseudo-first-order, pseudo-second-order and intra-particle diffusion models were studied, the results showed that the adsorption process conformed to the pseudo-second-order model, and the rate of this process was controlled by many steps. Furthermore, the removal efficiency of the adsorption kinetics reached 85% within 10 minutes. The results of the isotherm model and thermodynamics showed that the adsorption process was consistent with the Langmuir model and was mainly a spontaneous chemical endothermic process of monolayer. And the removal efficiency of the adsorbent reached 93% at the concentration of 400 mg/L, which can be expected to have a broad prospect in the treatment of CR industrial wastewater.

Kinetics studies on the adsorption of Methyl Orange and Metanil Yellow onto bottom ash: a comparative account

The focal point of the study lies in the comparative evaluation of the kinetic data involved in the eradication of toxic dyes from waste waters using the adsorption technique. The investigation reveals the dynamic adsorption behavior of two hazardous textile dyes viz. Metanil Yellow and Methyl Orange over bottom ash, an industrial waste material. The impact of several experimental parameters has been inspected using batch mode to acquire information on the ongoing mechanism. The graphical profiles obtained for the adsorption of Metanil Yellow and Methyl Orange onto bottom ash suggested an increase in the adsorption rate with time, with gradual attainment of equilibrium between the adsorbing species and adsorbent. The study revealed that second-order kinetics has been followed in both cases. Adsorption of Methyl Orange over bottom ash followed particle diffusion whereas film diffusion predominated in the case of Metanil Yellow.