Dye Removal by Adsorption: A Review

Abstract

This review discusses the methods for the removal of dyes from the wastewater effluents. Wastewater effluents contain synthetic dyes which cause a potential hazard to the environment hence these dyes need to remove from the water bodies. The various dye removal techniques are classified into Chemical, Physical, and Biological methods. Physical methods includes adsorption, ion exchange, and filtration/coagulation methods etc. while chemical methods includes ozonisation, Fenton reagent, photo catalytic reactions and biological methods include aerobic degradation, anaerobic degradation, biosorption etc. Adsorption found to be very effective and cheap method among the all available dye removal methods. Dyes from the industrial waste water effluents are effectively separated by using adsorbent such as activated carbon however its cost restricts the use in large scale applications. Experimental studies proved that the effective removal of dyes is obtained using several cheaply available non-conventional adsorbents also. Therefore, studies related to searching for efficient and low cost adsorbents derived from existing resources are gaining importance for the removal of dyes.

Bio-Removal of Methylene Blue from Aqueous Solution by Galactomyces geotrichum KL20A

“…For this reason, research on the application of biological processes as a method of dye degradation has been intensified in recent years due to the resulting low toxicity. Their high efficiency [9,10], which is due in part to the inherent capacity of the microorganisms to break down organic pollutants by using them as a source of carbon and energy, or by co-metabolism [11,12], has also contributed to intensified research. The use of yeasts for the bioremoval of toxic compounds has many advantages in comparison to filamentous bacteria and fungi, since they grow rapidly and have the capacity to adapt and resist unfavorable environments [13].…”

Dye Removal from Aqueous Solution using Low Cost Bioadsorbents Derived from Agricultural Waste: A Review

“…Eye & skin irritation, inhibition of protein-protein interaction, triggers genotoxicity in man Methyl orange Gene mutations, allergic dermites, cancer Malachite green Detrimental effects in liver, kidney, intestine and gonadotropic cells, damage of mitochondria, nuclear alterations Table 2: Hazardous effects of Methylene blue, eosin yellow, methyl orange and malachite green to human beings Different conventional techniques for dye removal can be widely grouped into physical, chemical and biological methods. Chemical approach include Fenton like reagent technique, ozonation, photo catalytic techniques and electrochemical destruction, physical approach includes adsorption, ion-exchange, filtration, coagulation and irradiation, while biological treatments include aerobic and anaerobic degradation, decolorization by white rot fungi and other microbial cultures [9,10]. The restriction in application of above mentioned methods may sometimes arise due to technical or economical feasibility.…”

“…There are mainly two types of adsorption: chemical adsorption (chemisorptions) or physical adsorption (physisorption). Chemical adsorption involves the formation of strong chemical bonds between adsorbate and adsorbent occurring due to exchange of electrons and the process is generally irreversible while physisorption involves the weak van der Waals intraparticle bonds between adsorbent and adsorbate or hydrogen bonds or dipole-dipole π-π interactions and hence the process mostly irreversible in most cases [10][11][12][13][14]. Different types of low cost adsorbents utilized for waste-water treatment can be classified as follows [10][11][12][13][14][15][16][17][18] The mechanism of adsorption of pollutant (dyes, metal ions etc.)…”

“…Chemical adsorption involves the formation of strong chemical bonds between adsorbate and adsorbent occurring due to exchange of electrons and the process is generally irreversible while physisorption involves the weak van der Waals intraparticle bonds between adsorbent and adsorbate or hydrogen bonds or dipole-dipole π-π interactions and hence the process mostly irreversible in most cases [10][11][12][13][14]. Different types of low cost adsorbents utilized for waste-water treatment can be classified as follows [10][11][12][13][14][15][16][17][18] The mechanism of adsorption of pollutant (dyes, metal ions etc.) on adsorbate can be briefly explained by occurrence of series of following consecutive steps [11,13,19,20]: The properties of dye solution affecting the removal efficiency of dye from aqueous solution are ionic strength, presence of other contaminants, pH, and initial concentration, dosage of adsorbent, temperature and agitation time.…”

Synthesis of mesoporous SiO2 from rice husk for removal of organic dyes in aqueous solution

“…[1] Therefore, the organic dyes should be treated before releasing into environment. [2] Various treatment methods such as coagulation, biological degradation and ion exchange, [3] but adsorption is still widely used for removing organic dyes due to its simplicity and high efficiency.…”