Various Types Of Dyes Research Articles

Natural Dyes: A Comprehensive Review on Medicinal Plant-based Pigments and Culinary Herbs as Flavor Enhancers

The global demand for natural dyes has surged, propelled by a growing awareness of the therapeutic properties inherent in these dyes. Derived from a variety of sources such as plants, insects, animals, and minerals, natural dyes have garnered attention as safer alternatives to synthetic colorants, many of which have been banned due to their potential to cause allergy-like symptoms or pose carcinogenic risks. Notably, plant-based pigments among natural dyes exhibit a diverse array of medicinal values. This review provides an in-depth exploration of various types of dyes, highlighting the distinctions between natural and synthetic counterparts and delvloping into their wide-ranging applications. The adverse effects associated with synthetic dyes are discussed, emphasizing the need for sustainable alternatives. The paper also offers a compilation of information on synonyms, biological sources, chemical constituents, and uses found in naturally occurring dye-yielding plants, aiming to contribute to the development of pharmaceutical and cosmeceutical formulations. This comprehensive review amalgamates the realms of natural dyes and culinary herbs, offering valuable insights into their medicinal and culinary significance.

Tailoring the properties of SnS thin films deposited at room temperature by varying the amount of complexing agent for enhanced photocatalytic activity

This work examines how the characteristics and photocatalytic efficacy of modified SILAR-deposited SnS thin films are affected by the addition of a complexing agent. Stannous chloride dihydrate and sodium sulphate were used as tin and sulphur sources, respectively, while triethanolamine (TEA) served as a complexing agent in film deposition. The modified SILAR method facilitated the formation of well-adhesive thin films on the glass substrate at room temperature. The formation of SnS was demonstrated using EDAX and XPS analysis. XRD analysis proved that all the films are polycrystalline in nature with an orthorhombic crystal structure. The presence of chlorine as an involuntary dopant was observed in all the films prepared with TEA. Optical studies employing UV–visible spectroscopy found that all of the films have good visible absorption, with bandgap values ranging from 1.58 eV to 2.2 eV. Even though the films were deposited at room temperature, all films exhibited good thermal stability as per TGA analysis. The introduction of TEA caused improvements in the adhesion of the film to the substrate, a decrease in the band gap, a change in the morphology and composition, and an increase in the crystallinity and crystallite size. Due to their suitable bandgap corresponding to the visible region, SnS thin films exhibited good photocatalytic efficiency in degrading various types of dyes. The SnS thin film catalyst reduced 97% of methylene blue in 90 min at room temperature without using any reducing agent. The LCMS analysis validated the photocatalytic degradation of dye, whereas the UV–visible spectroscopic analysis gave a quantitative measure of the degradation efficiency. The reduction in photodegradation efficiency in the presence of OH radical scavengers confirmed the role of OH radicals in the degradation process. The terephthalic acid test further demonstrated the generation of OH radicals during the dye degradation process. The observed increase in photocatalytic activity of SnS thin films with TEA addition could be due to TEA-induced bandgap reduction, crystallinity increase, and crystallite size increase. The catalyst was reusable, stable, easy to recover after use, and effective against various kinds of dyes. The study emphasizes the use of complexing agents as a useful tool for modifying the characteristics and, consequently, the photocatalytic efficiency of modified SILAR-deposited SnS thin films.

A super-efficient gel adsorbent with over 1000 times the adsorption capacity of activated carbon

It was observed that a super-efficient gel adsorbent system (RRQG@CDC) could be obtained when a matrix material of polyquaternium gel with a flat distribution (RRQG) was loaded onto a skeleton material of cyclodextrin carbide (CDC). The results showed that the adsorption capacity of RRQG@CDC towards dyes was 1250 times higher than that of commonly used activated carbon, enabling highly efficient purification of dyeing wastewater through superior adsorption. In addition, RRQG@CDC demonstrated adaptability to a range of different pH values and salinity conditions, showing super-efficient adsorption abilities towards various types of dyes. Moreover, simulated scale-up tests confirmed the feasibility of this super-efficient adsorbent for practical engineering applications. An enhanced quasi-planar electrostatic adsorption mechanism model was established, which has changed the traditional understanding of adsorption mechanisms. Furthermore, the waste residues of RRQG@CDC, after dye adsorption, can be directly utilized as high-calorific fuels, showcasing the resourcefulness of these residues while eliminating the risk of secondary pollution. In conclusion, this study achieved a remarkably efficient and resource-based purification of dyeing wastewater by developing a highly effective adsorbent system.

Biodegradation of Malachite Green Dye by Novel Isolated Bacillus Species AAV from Garden Soil

Malachite green (MG) dye commonly use in textile and paper printing industry to a great extent. Textile effluent released from industries including dyes must be treated before release into the environment due to its toxic nature. In present study, newly isolated bacterial species was able to decolorize MG dye (100%) in 1 h at shaking condition and 94% at static condition. 16S rRNA analysis revealed an isolate as Bacillus sp. AAV. Lignin peroxidase, laccase and tyrosinase enzymes from Bacillus sp. AAV showed significant increased activity during decolourisation. There was 138, 369 and 164% trek in activity of LiP, laccase and tyrosinase after MG decolourization, respectively. Bacillus sp. AAV could decolourise MG efficiently at alkaline pH (8-10) and at 40°C temperature. Biodegradation was monitored by UV-VIS spectrophotometer. Gas chromatography-Mass spectroscopy data was used to propose the degradation pathway of MG dye. The newly isolated Bacillus sp. AAV was able to decolourise ten various types of dyes and textile dye effluent. Phytotoxicity test by using seeds of wheat and sorghum was also carried out to check toxicity of MG dye metabolites. The study reveals that there was no toxicity with respect to tested seeds. This study suggests that Bacillus sp. AAV could be a useful microorganism or its enzyme system for textile dyes and effluent treatment.

Synthesis, characterization, and effective removal of dye pollutants from water bodies using a new ZnO nanocomposite

Biogenic zinc oxide nanocomposites were fabricated through an eco-friendly method by employing Boerhaavia diffusa leaf extract in combination with zinc nitrate. The nanocomposites underwent a comprehensive characterization process involving uv–visible spectroscopy (UV-DRS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), selected area diffraction (SAED), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDAX), high-resolution transmission electron microscopy (HRTEM), inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF), and zeta potential studies. The XRD analysis substantiated the existence of a ZnO nanocomposite possessing a hexagonal wurtzite crystalline structure. Furthermore, extended rod-shaped formations were identified in conjunction with clusters of sodium and potassium.The effectiveness of the ZnO nanocomposite in photocatalytic degradation was assessed for various types of dyes: cationic and anionic like Methylene Blue (MB), Malachite Green (MG), Congo Red (CR), and Methyl Orange (MO) in aqueous medium. The nanocomposites demonstrated remarkable photodegradation capabilities for both cationic and anionic dyes. Notably, 50 mg of the catalyst effectively removed Congo Red (15 ppm) and Methylene Blue (15 ppm) within 40–60 min under direct sunlight and 15–30 min under UV illumination. The samples are more active on UV light illumination rather than exposure to sunlight due to.the favorable semiconductor band gap (3.26 eV). As a result, this research suggests an uncomplicated, budget-friendly, and environmentally sustainable approach for manufacturing a ZnO-based photocatalyst. Moreover, the inclusion of potassium and sodium elements in the nanocomposite showcased a beneficial synergistic impact on its photoactivity. This necessitates additional scrutiny for its potential application in treating diverse organic pollutants in water resources. Additionally, high efficiency of the catalyst under direct sunlight holds potential for applications in solar cells.

A novel aminated Fe3O4/GO/carboxylated cross-linked β-CDP composite for effective sorption of cationic and anionic dyes from water

A novel adsorbent, aminated Fe3O4 (Fe3O4-NH2)/graphite oxide (GO)/carboxylated cross-linked β-cyclodextrin polymer (CDP-COOH) composite, was fabricated for influential removal of various types of dyes from waters. The morphology and structure of resulting Fe3O4-NH2/GO/CDP-COOH composite was studied by SEM, two-dimensional EDS map, FTIR, WAXD, XPS, TGA, and zeta potential meter, and its saturation magnetization was determined to be 46.3 emu/g by VSM. The maximal sorption capacities of Fe3O4-NH2/GO/CDP-COOH composite for methylene blue (MB, as a model of cationic dyes) and Congo red (CR, as a model of anionic dyes) at 303 K were 201.75 mg/g and 2211.05 mg/g, respectively, which can be mainly assigned to multiple adsorptive forces like electrostatic attractions, hydrogen bonds, host–guest self-assembly interactions, π-π electron cloud interactions, and Lewis acid-base interactions. The dye sorption by the Fe3O4-NH2/GO/CDP-COOH composite had a spontaneous nature according to the sorption thermodynamic calculation and can be well explained by pseudo-second-order model. The Langmuir and Freundlich models could explain the sorption isotherms of Fe3O4-NH2/GO/CDP-COOH composite for MB and GO, respectively. The Fe3O4-NH2/GO/CDP-COOH composite possessed many other advantages including the good sorption capability for different heavy metal ions (like Pb2+, Ni2+, and Cu2+) and organic compounds (like dichlorophenol and propranolol) as well as the good recyclability and reusability.

Maximum permissible technological parameters of frame-filling filters

Relevance. Wastewater of knitting industry contains various types of dyes, synthetic surfactants, mineral salts and suspended solids in values requiring deep cleaning. It is advisable to carry out deep cleaning of these drains on non-pressure filters, which do not require large expenses and are easy to operate. We gave preference to frame-filling filters. First of all, it allows significant increase in filtration rate, and its two layers with different fractions of filter materials significantly contributes to differentiated purification of wastewater from suspended solids of various sizes. Aim. To determine the maximum permissible values of technological parameters of the frame-filling filters operation (filtration rate and duration of the filter cycle) at which high filtration effect is provided through a highly porous material-crushed expanded clay. Objects. Wastewaters of the knitting industry and the effluents of the cotton and textile industries that are similar in their composition of pollution, as well as the identical effluents of some other branches of light industry. Methods. The experimental method was used on a laboratory frame-filling filter installation. The expanded clay used was obtained by the method of swelling low-melting clays and clay rocks during their rapid firing, followed by crushing to the state of sand. In general, the proposed technological methods are justified by those comparative and generalizing methods that can improve frame-filling filter operation. Results and conclusions. Based on the results of the conducted research, the following conclusions can be drawn: Pronounced intergranular porosity (on average 1.6 times greater than that of quartz sand) allows expanded clay granules passing through a significant amount of waste water at relatively high filtration speeds (20–22 m h) and retain up to 70% of suspended solids The duration of the filter cycle when using crushed expanded clay is at least 1.5 times longer than when using quartz sand Due to the greater difference in the average coefficients of the shape of the filtering materials, more complete regeneration of filtering properties of crushed expanded clay compared to quartz sand is provided 2–3 minutes earlier, regardless of the initial concentration of suspended substances. The filtering properties of crushed expanded clay during deep wastewater treatment of the knitted production with the main concentrated pollution indicators (color intensity, BODfull, COD and surfactants) practically do not concede the quartz sand properties. Besides, crushed expanded clay is much cheaper than quartz sand; it can be used on an equal footing with quartz sand for deep cleaning of low-turbidity and slightly colored industrial wastewater.

Adsorption of Remazol Brilliant Blue R Dye Using Activated Carbon from Emty Palm Oil Bunches

Various types of dyes are used in the textile industry, including Remazol Brilliant Blue R dye. Remazol dye is a type of anthraquinone which is very difficult to remove if it is contaminated in the environment. One method of dealing with dyes that pollute the environment is adsorption using activated carbon. The material for activated carbon has the most potential to come from the palm oil industry, namely empty palm fruit bunches because they are widely available and have economic value. This study aimed to determine the effect of varying exposure time between activated carbon made from empty palm fruit bunches and textile dye Remazol Brilliant Blue R on decreasing the concentration of dye Remazol Brilliant Blue R. The adsorption process was carried out with the ratio of adsorbent mass: dye volume w/v (0.1:15) and varying the contact times of 20, 40, 60, 80, 100 and 120 minutes. The initial concentration of textile substances was 23.2121 mg/L and was contacted between Remazol Brilliant Blue R textile substances with adsorbents using a shaker. Analysis of adsorption results using a UV – Vis instrument with a wavelength of 670 nm for Remazol Brilliant Blue R dye. The results showed that the best adsorption conditions was 60 minute contact time, with a removal percentage of 87.23% with an adsorption capacity of 3.0373 mg/g. The adsorption of Remazol Brilliant Blue R follows the Langmuir adsorption equation model with an R2 of 0.9997.

Chemically programmable bacterial probes for the recognition of cell surface proteins.

Common methods to label cell surface proteins (CSPs) involve the use of fluorescently modified antibodies (Abs) or small-molecule-based ligands. However, optimizing the labeling efficiency of such systems, for example, by modifying them with additional fluorophores or recognition elements, is challenging. Herein we show that effective labeling of CSPs overexpressed in cancer cells and tissues can be obtained with fluorescent probes based on chemically modified bacteria. The bacterial probes (B-probes) are generated by non-covalently linking a bacterial membrane protein to DNA duplexes appended with fluorophores and small-molecule binders of CSPs overexpressed in cancer cells. We show that B-probes are exceptionally simple to prepare and modify because they are generated from self-assembled and easily synthesized components, such as self-replicating bacterial scaffolds and DNA constructs that can be readily appended, at well-defined positions, with various types of dyes and CSP binders. This structural programmability enabled us to create B-probes that can label different types of cancer cells with distinct colors, as well as generate very bright B-probes in which the multiple dyes are spatially separated along the DNA scaffold to avoid self-quenching. This enhancement in the emission signal enabled us to label the cancer cells with greater sensitivity and follow the internalization of the B-probes into these cells. The potential to apply the design principles underlying B-probes in therapy or inhibitor screening is also discussed here.

Kinetic studies on the persulfate oxidation of methylene blue in the absence and presence of silver(I) as a catalyst in aqueous and micellar media

AbstractThe kinetics and mechanism of the oxidative decolorization of methylene blue (MB+) as a cationic dye by persulfate using silver(I) catalyst in aqueous acidic medium were studied. The effects of different parameters like [H+], [Ag+], reactant concentration, micelles, and temperatures were investigated. The kinetic data showed that the oxidative decolorization of [MB]+ by persulfate obeyed pseudo‐first‐order kinetics by taking a large excess of [S2O82−] over [MB+]. The observed rate constant increases with increasing of [H+]. A plausible mechanism for the silver(I) enhanced decolorization of [MB]+ by persulfate is suggested which is consistent with the experimental rate law. The effect of micelles such as SDS and Triton X‐100 on the reaction rate is investigated. The rate of reaction decreases with increasing [SDS] but is not affected by Triton X‐100. The mechanism of the electron transfer process between [MB]+ and S2O82– proceeds through an outer‐sphere mechanism. Thermodynamic activation parameters ΔH* and ΔS* were calculated. The experimental data may be useful for the layout of wastewater treatment containing various types of dyes.

Dyes removal from textile wastewater by agricultural waste as an absorbent – A review

Water pollution from the textile industry affects environmental conditions by generating large-scale effluent mixed with various dyes. Dyes are mostly organics with multiple compound structural and molecular weight variations; if not managed properly before release, they may harm the environment and organism. However, many dyes are categorized into distinct groups, and various adsorbents for dye adsorption have been identified. Among these dyes, methyl dyes, which come in multiple colours, are the most popular in research due to their availability and accessibility. It is imperative to use effective treatments using special adsorbents to remediate water contamination before discharging into streams. As awareness of environmental issues increases with time, the need for a wide range of adaptive alternative feedstock that satisfies ecological regulations has become a priority for researchers worldwide. Therefore, there is a need to develop other adsorbents from alternatively economic raw materials such as locally available industrial and mineral waste and by-products. Additionally, numerous materials have been used, prepared, or grafted from various agricultural peel-based adsorbents. Biomass is a significant source of renewable adsorption processes for hazardous compounds, including toxic organics and metals/elements. It is much cheaper, has abundance, effective adsorption capability, and reusability, have numerous advantages over conventional materials. This review focuses on using plant agricultural wastes to remove dyes. Different adsorption capacities, operating conditions, and application forms have been investigated. The adsorption kinetics and isotherms are demonstrated to illustrate the adsorbent's properties and adsorption mechanisms. • Agricultural waste is valuable because it is inexpensive, abundant, and resilience and is utilized to adsorb and remove various types of dyes. • The agricultural waste (organic peels, seeds, and leaves) demonstrated its remarkable efficacy in removing contaminants from water. • This research is gaining much attention and prominent.

Eggplant biomass based porous carbon for fast and efficient dye adsorption from wastewater

Adsorption techniques have been successfully applied in water purification for their simplicity, efficiency, and negligible byproducts. Porous carbon materials are effective dye adsorbents but have relatively low adsorption efficiency, slow adsorption rate, and high production cost, all of which need to be addressed for conducive practical applications. Herein, natural eggplant-based porous carbon materials (EPCMs) have been studied and successfully constructed to perform with high efficiency and fast rate of removal of dyes from wastewater. The hierarchical pore structure and well-developed mesoporous had a total pore volume of 0.6379 cm 3 /g and a maximum specific surface area of 516.0060 m 2 /g, which contributed to the high efficiency of adsorption (100%). The complete adsorption of Rhodamine B (basic and cationic dyes) solution within 25 min demonstrated its fast and high adsorption performance. The EPCMs also showed its efficiency in the absorption of various dyes, including methyl orange (acidic and anionic dye), methylene blue (basic and cationic dyes), and Yuan’qing B (reactive dye). Furthermore, the EPCMs were tested with actual wastewater from a production-based factory and recorded excellent removal effects as well, suggesting its prospective expansion for industrial applications. Therefore, this eggplant biomass-based porous carbon provides a promising approach for fast and highly efficient wastewater purification from dye-based contaminations. • Eggplant biomass carbon is developed for dye adsorption from wastewater. • The EPCMs show fast and high-efficient dye adsorption capacity. • The EPCMs can remove various types of dyes with high efficiency. • The EPCMs exhibit excellent removal effects for the actual dyeing wastewater.

Modified Composite Based on Magnetite and Polyvinyl Alcohol: Synthesis, Characterization, and Degradation Studies of the Methyl Orange Dye from Synthetic Wastewater.

The goal of the present paper was to synthesize, characterize, and evaluate the performance of the modified composite based on magnetite (Fe3O4) and polyvinyl alcohol (PVA). The obtained composite was used to degrade Methyl Orange dye from synthetic wastewater by a laboratory photocatalytic reactor. Various parameters of the photodegradation process were tested: composite dosage, amount of hydrogen peroxide (H2O2), and pH. The composite was characterized by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The degradation experiments indicated that the complete dye decolorization depended on the amount of H2O2. In addition, the H2O2 could accelerate Methyl Orange degradation to more highly oxidized intermediates in the presence of UV light (99.35%). The results suggested that the obtained modified composite could be used to treat wastewater containing various types of dyes.

Review effect of various types of dyes and structures in supporting performance of dye‐sensitized solar cell TiO 2 ‐based nanocomposites

The energy demand for supporting the activity of human life is increasing where fossil fuels decreasing sharply every year and have an impact on increasing CO2 emissions in the environment. An alternative solution for providing practical energy needs is using renewable energy such as solar cells. For environmentally friendly, economical, and efficient concepts, dye-sensitized solar cell (DSSC) is a promising alternative for the photovoltaic field. The performance of a DSSC depends on many factors, such as electron collection at the photoanode, photoanode light-harvesting efficiency, and others. In this review article, we observe the influence of synthetic and natural dye materials on light-harvesting efficiency at photoanodes. The chemical structure of dyes plays an essential role in increasing photon absorption, thereby increasing electron injection and conversion efficiency. In addition to dyes, we also reviewed the influence of the shape of the DSSC structure, namely the sandwich, monolithic, and honeycomb structures, on the performance of DSSCs. This approach helps develop a narrative about the potential and relationship of dyes and structure in increasing efficiency as a guide for synthesizing new materials in the future.

Pengolahan Limbah Pewarna Metilen Biru Menggunakan Arang Aktif dan Zeolit Aktif dengan Katalis Fe dan Oksidator Hidrogen Peroksida

The textile industry including batik has provided broad benefits to society from an economic standpoint. However, there is negative impact from wastewater generated in the production process, which is containing dyes. Various types of dyes are used in the coloring process, and methylene blue is one of most used dye. Various ways have been done to treat wastewater containing methylene blue. Methylene blue processing techniques by adsorption have been carried out with various types of adsorbents. Research on the comparison of the ability of commercial activated charcoal and commercial activated zeolite to adsorb methylene blue was carried out with the addition of an Fe catalyst and a hydrogen peroxide oxidizer. The results showed that the addition of Fe catalyst would increase the degradation of methylene blue in the waste either with activated charcoal or activated zeolite. The combination of using Fe catalyst and hydrogen peroxide oxidizer further increases the removal of methylene blue in both types of adsorbents, activated charcoal and activated zeolite. Activated zeolite has the better ability to adsorb methylene blue than activated charcoal under various conditions.

Catalytic Reduction of Toxic Dyes Using Highly Responsive and Stable Ag Nanocomposite

The objective of study is preparing multi-responsive, nontoxic, and highly stable nanocomposite hydrogels for effective reduction and decolonization of broad spectrum of toxic dyes. The nanocomposite hydrogels are composed of N-isopropy acrylamide, acrylic acid, and silver/chitosan nano-dispersion and prepared by the effect of Gamma radiation at a dose rate of 2.6 kGy/h. The physical and chemical properties of the various prepared nanocomposites hydrogels were studied by various techniques as SEM, TEM, XRD, and FTIR. The swelling properties of the nanocomposites hydrogels were studied under various conditions as pH and temperature. Given the physical properties of multifunctional thermo-responsive N-isopropy acrylamide, acrylic acid hydrogel, and its Ag nanocomposite, they hold the strong potential for toxic dyes degradation as Erioglaucine as a model dye. In this paper, we review various silver and thermo-responsive poly (N- isopropylacrylamide/Acrylicacid /silver), (PNIPAM/AA/Ag) nanocomposites and highlight their high activity as a catalyst for degradation of various types of dyes.

Mass fabrication of oxygen and nitrogen co-doped 3D hierarchical porous carbon nanosheets by an explosion-assisted strategy for supercapacitor and dye adsorption application

The mass fabrication of heteroatom-doped 3D hierarchical porous carbon nanosheets plays an important role in developing high-performance supercapacitor electrode materials and dye adsorbent. In this work, a simple and feasible explosion-assisted strategy was proposed, in which only glucose and magnesium nitrate were used as a reactant to fabricate a series of heteroatom-doped 3D hierarchical porous carbon nanosheets (HPCNS) on a large scale. The obtained HPCNS-1.0 possesses abundant porous structure as well as an ultrahigh oxygen content (16.08 at. %) and an outstanding specific surface area (SSA, 1378 m2 g−1). As an active electrode material, the specific capacitance for HPCNS-1.0 is 253 F g−1 at the current density of 1 A g−1 and 168 F g−1 at 20 A g−1, demonstrating its high rate capability (66%). The specific capacitance only loses 1.3% after 5000 cycles at 10 A g−1, indicating its outstanding cycle stability. As an adsorbent for dye adsorption, the HPCNS-1.0 shows good adsorption capability towards various types of dyes, especially methylene blue with the uptake of 561 mg g−1 at 25 °C. Our work provides a cheap and efficient way to develop high performance 3D hierarchical porous heteroatom-doped carbon nanosheets on a large scale.

Vasculature-Staining with Lipophilic Dyes in Tissue-Cleared Brains Assessed by Deep Learning

Visualization of the vasculature in three dimensions (3D) has become attractive, particularly in stroke models. 3D-reconstruction is aided by tissue-clearing, where the transparency allows imaging of fluorescent probes in deeper structures. The vasculature is commonly stained by fluorescent lipophilic dyes that are incorporated into the wall during transcardial perfusion. Nevertheless, tissue clearing involves extracting the light-scattering lipids, and hence also the lipid-appended dyes. The wash-out likely depends on dye and its aldehyde-fixability. Fixation secures cross-linking to proteins and hence retainment in the tissue. However, the compatibility of various types of dyes is largely unknown. We tested and compared 9 different dyes for vasculature staining and tolerance to lipid clearing, which was quantified using deep learning image segmentation. Among the dyes, we found a subset that is both cost-effective and compatible with tissue lipid clearing. We suggest these dyes will provide a valuable tool for future investigations.

Bioremediation of dyes using coconut parts via adsorption: a review

Coconut (Cocos nucifera) is a palm tree belonging to the Arecaceae family that possesses a thousand and one uses. Each part of the tree has it’s uses and can be made into products. Also, various parts of the coconut tree have been utilized to remove various types of dyes from water and waste water via chemical, physical and biological methods. Adsorption is one of the widely used physical methods over their counterparts owing to cost efficiency and ease in handling. The key parameters for the adsorption process are the initial concentration of adsorbate, dosage of adsorbent, the pH and contact time. Additionally, the kinetic parameters, equilibrium isotherm and thermodynamics of the adsorption of dyes on the adsorbent were explored.

Azo-dye degradation by Mn–Al powders

Manganese–Aluminum powders were recently reported to show high efficiency and fast reaction rates as decolorization materials for azo-dye aqueous solutions. This work presents a detailed study of different aspects of this material. Firstly, the influence of the crystalline phase and the microstructure was studied by comparing the efficiency of powders obtained by different production protocols. Secondly, the decolorization efficiency was investigated on various types of dyes, including real textile wastewater samples. The analysis of the treated water and the particles showed that the main reaction mechanism was the breaking of the azo-dye molecules, although important adsorption on the metallic surface was observed for some colorants. Finally, the reusability of the particles and the reduction of toxicity achieved during the treatments were assessed. The simple production and application methods, the high efficiency and the use of environmentally friendly metallic elements are the main advantages of Manganese–Aluminum powders compared to other high-efficient decolorizing metallic materials.