Search

Organic dye molecules and pathogenic microorganisms exist widely in printing and dyeing wastewater, causing persisting concerns about water environment safety. Herein, newly developed alginate–chitosan–graphene oxide nanosheets gel beads with both exceptional adsorption and antibacterial functions are reported. NaHCO3 is selected as porogen and Ag+ is used as antibacterial enhancer. The adsorption properties of the beads fit well with the Langmuir isotherm and pseudo‐second‐order model, suggesting a monolayer behavior of the adsorption and their reaction rate is controlled by chemisorption. The theoretical liminal value of the adsorption of methylene blue by the beads reaches 847.46 mg g−1. After five adsorption–desorption cycles, the beads retain almost intact adsorption activity, and the sterilization rates of Escherichia coli and Staphylococcus aureus remain at 99.99%. The results give insight into developing new processing routes for constructing gel beads for versatile applications. [ABSTRACT FROM AUTHOR]

Organic dye‐contained wastewater is a major threat to the global environment and public health. In this study, natural wood and MoS2 are combined to create effective photocatalysts for removing organic pollutants from water under light irradiation. The results show that the photocatalytic degradation activity of wood/MoS2 composites are obviously superior to that of natural wood under solar light as well as possess outstanding stability after three reaction cycles. The improvement in photocatalytic performance for photodegradation is primarily due to an increase in specific surface area and the introduction of catalytic active sites from the edge S, which favors adsorption of organic pollutants and accelerates the degradation process. The synergistic effect of adsorption and photocatalysis also ensures that the composited catalyst is highly universal in its application to organic dye degradation, including RhB (Rhodamine B), MB (Methylene Blue), and MO (Methyl Orange); the kinetic constant for the photocatalytic degradation of RhB, MO, and MB are 0.040, 0.035, and 0.032 min−1, respectively and the degradation performance can be well maintained after three cycle tests. Our study has proved that the wood/MoS2 composite is a novel, low‐cost photocatalyst that plays an important role in environmental protection. [ABSTRACT FROM AUTHOR]

In this work, raw sunflower seed shell particles (RSSSP) as a green adsorbent were used to remove disperse red 1 (DR1), crystal violet (CV), and malachite green (MG), and methylene blue (MB) dyes from synthetic wastewater. Various analyzes, including fourier transform infrared, field‐emission scanning electron microscopy, transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, and Brunauer–Emmett–Teller analysis, were performed, which determined the morphology, particle size, surface area, and pore size of RSSSP. The effect of environmental factors on the adsorption ability of the RSSSP was investigated in detail. The results of this study showed that RSSSP has high adsorption efficiency toward organic dyes, and was comparable with other natural and synthetic adsorbents. The results showed that Freundlich isotherm and pseudo‐second‐order models describe the adsorption of the dye onto RSSSP. Additionally, the maximum adsorption capacity of DR1, CV, MG, and MB onto RSSSP was found to be 85, 81, 120, and 98 mg/g, respectively. Furthermore, the calculated thermodynamic parameters showed that the adsorption process of the studied dyes was exothermic. In addition, the RSSSP can be used in several adsorption–desorption cycles. The calculated efficiency for textile wastewater based on the COD test is 90% using RSSSP. Finally, the RSSSP could be used as an efficient low‐cost adsorbent for the adsorption of industrial dyes from wastewater. [ABSTRACT FROM AUTHOR]

Organic dyes, present in the aquatic environment, have negative effects on ecosystems. Attempts are being made to remove these dyes by using number of physio‐chemical methods. Out of all the methods, adsorption technique is the most economical and efficient technique. For this purpose, efficient and cost‐effective adsorbents are needed. Neem leaf powder (NLP) containing Azadirachtin Indica, has been used for methylene blue (MB) dye removal. The interaction of dye on neem leaf containing Azadirachta indica plays an important role. Quantum mechanical calculations using density functional theory have been done in order to have an idea about interaction during adsorption. There is a possibility of both strong and weak interaction depending on the orientation of adsorbent and adsorbate. [ABSTRACT FROM AUTHOR]

Modeling and simulation of batch adsorption of the organic dye methylene blue (MB) by modified metal‐organic framework‐5 (MOF‐5) were investigated. The reported data on the adsorption of MB dye onto Wells‐Dawson acids (H6P2W18O62)‐immobilized MOF‐5 were employed. The film‐pore diffusion model was developed based on external mass transfer coefficient and pore diffusion coefficient that govern the mass transfer process in batch organic dye adsorption. Applying the estimated parameters, the MB adsorption by using modified MOF‐5 was examined to evaluate the effects of MOF‐5 modification, initial dye concentration, temperature, and the dosage of adsorbent. The adsorption capacity of modified MOF‐5 (H6P2W18O62/MOF‐5) was higher than pure MOF‐5. Besides, a lower initial MB dye concentration, higher temperature, and lower adsorbent dosage resulted in higher MB dye adsorption capacity. [ABSTRACT FROM AUTHOR]

A MOF named [(CH3)NH2] [H2N(CH3)2][ZnTNC4A] ⋅ 4H2O (ZnTNC4A) was synthesized by a resorcinol[4]arene functionalized tetracarboxylic acid ligand (TNC4A=2,8,14,20‐tetra‐1‐naphthalene‐6,12,18,24‐tetramethoxy‐4,10,16,22‐ tetracarboxyl‐methoxy‐resorin[4]arene). The three‐dimensional framework with one‐dimensional channels of ZnTNC4A was characterized by elemental analysis, powder X‐ray diffraction, thermogravimetry, UV‐vis diffuse reflection spectrum, infrared spectrum and N2 adsorption analyse. In addition, ZnTNC4A shows the ability of selective adsorption of methylene blue with a pseudo‐second order kinetic model. The selective adsorption kinetics of a series of dyes showed that the ion exchanged separation process was related to the size and charge of organic dyes. [ABSTRACT FROM AUTHOR]