Harmful Organic Dyes Research Articles

Crystal to Hydrogel Transformation in S-Benzyl-L-Cysteine-Containing Cyclic Dipeptides - Nanostructure Elucidation and Applications.

Cyclic dipeptides (CDPs) are crucial building blocks for a range of functional nanomaterials due to their simple chemical structure and high molecular stability. In this investigation, we synthesized a set of S-benzyl-L-cysteine-based CDPs (designated as P1-P6) and thoroughly examined their self-assembly behavior in a methanol-water solvent to elucidate the relationship between their structure and gelation properties. The hydrophobicity of the amino acids within the CDPs was gradually increased. The present study employed a comprehensive array of analytical techniques, including NMR, FT-IR, AFM, thioflavin-T, congo-red CD, X-ray crystallography, and biophysical calculations like Hirshfield Surface analysis and DFT analysis. These methods revealed that in addition to hydrogen bonding, the hydrophobic nature of the amino acid side chain significantly influences the propensity of CDPs to form hydrogels. Each CDP yielded distinct nanofibrillar networks rich in β-sheet structures, showcasing unique morphological features. Moreover, we explored the practical application of these CDP-based hydrogels in water purification by utilizing them to remove harmful organic dyes from contaminated water. This application underscores the potential of CDPs in addressing environmental challenges, offering a promising avenue for the future development of these materials in water treatment technologies.

Recent progress in defect-engineered metal oxides for photocatalytic environmental remediation.

Rapid industrial advancement over the last few decades has led to an alarming increase in pollution levels in the ecosystem. Among the primary pollutants, harmful organic dyes and pharmaceutical drugs are directly released by industries into the water bodies which serves as a major cause of environmental deterioration. This warns of a severe need to find some sustainable strategies to overcome these increasing levels of water pollution and eliminate the pollutants before being exposed to the environment. Photocatalysis is a well-established strategy in the field of pollutant degradation and various metal oxides have been proven to exhibit excellent physicochemical properties which makes them a potential candidate for environmental remediation. Further, with the aim of rapid industrialization of photocatalytic pollutant degradation technology, constant efforts have been made to increase the photocatalytic activity of various metal oxides. One such strategy is the introduction of defects into the lattice of the parent catalyst through doping or vacancy which plays a major role in enhancing the catalytic activity and achieving excellent degradation rates. This review provides a comprehensive analysis of defects and their role in altering the photocatalytic activity of the material. Various defect-rich metal oxides like binary oxides, perovskite oxides, and spinel oxides have been summarized for their application in pollutant degradation. Finally, a summary of existing research, followed by the existing challenges along with the potential countermeasures has been provided to pave a path for the future studies and industrialization of this promising field.

Facile Synthesis of Band Gap-Tunable Kappa-Carrageenan-Mediated C,S-Doped TiO2 Nanoparticles for Enhanced Dye Degradation.

Semiconducting nanoparticles (SNPs) have garnered significant attention for their role in photocatalysis technology, offering a cost-effective and highly efficient method for breaking down organic dyes. Of particular significance within SNP-based photocatalysis are tunable band gap TiO2 nanoparticles (NPs), which demonstrate remarkable enhancement in photocatalytic efficiency. In the present work, we introduce an approach for the synthesis of TiO2 NPs using kappa-carrageenan (κ-carrageenan), not just as a reducing and stabilizing agent but as a dopant for the resulting TiO2 NPs. During the synthesis of TiO2 NPs in the presence of sulfate-rich carrageenan, the process predominantly leaves residual sulfur and carbon. The presence of residual carbon, in conjunction with sulfur doping, as indicated by fast FTIR spectra, XPS, and EDX, leads to a significant reduction in the band gap of the resulting composite to 2.71 eV. The reduction of composite band gap yields remarkable degradation of methylene blue (99.97%) and methyl orange (97.84%). This work presents an eco-friendly and highly effective solution for the swift removal of environmentally harmful organic dyes.

Facile synthesis and grafting of N2O2‐Cu(II) Schiff base complex onto graphene oxide surface: Aspects of its antimicrobial, anticancer, antiCOVID‐19 and photodegradation of methylene blue

AbstractIn this study, a facile synthesis and grafting method is reported for tetradentate Cu(II) Schiff base complex onto the surface of graphene oxide (GO). The Schiff base Cu‐complex was synthesized through the condensation reaction between 2,3‐diamino pyridine and 2‐hydroxy‐1‐naphthaldehyde, followed by the addition of Cu(II) ion to afford N2O2‐Cu(II) complex. The GO was prepared through a modified Hummers’ method and characterized using various spectroscopic and microscopic techniques. The Schiff base Cu‐complex was then grafted onto the surface of GO via a simple solution‐phase reaction, resulting in the formation of N2O2‐Cu(II) Schiff base/GO composite. The fabricated composite was characterized using FTIR spectroscopy, UV–vis, X‐ray diffraction (XRD), and scanning electron microscopy (SEM). Importantly, the prepared N2O2‐Cu(II) Schiff base complex exhibited excellent DNA interaction as well as efficient antimicrobial and anticancer activities. Additionally, it demonstrated potent anticancer activity against hepatocellular carcinoma cells (HepG‐2), and colon cancer cells (HCT‐116) and exhibited promising activity against the COVID‐19 receptor (PDB ID: 6LU7) along with the human DNA receptor (PDB ID: 1BNA). Furthermore, this fabricated heterogeneous catalyst showed enhanced photodegradation of MB with ≈92% conversion and four times recyclability. The overall results suggest that the Cu(II) Schiff base/GO composite has potential applications in various medical and environmental fields, including photodegradation/elimination of harmful organic dyes for water treatment applications.

Green synthesis of carbon quantum dots from teak leaves biomass for in situ precipitation and regenerative-removal of methylene blue-dye.

The objective of this study was to completely eliminate environmentally harmful cationic organic dye from aqueous solutions using the one-step ultrasonication method, renowned for its energy efficiency, user-friendliness, and minimal requirement for chemical resources, making it particularly suitable for large-scale applications. To achieve effective environmental remediation, we employed carbon dots derived from teak leaf biomass (TBCDs) layered with graphene oxide. We conducted a thorough characterization of the TBCDs using UV-vis spectroscopy (with absorption peaks at λmax = 208 and 276nm), FTIR spectroscopy (confirming the presence of various functional groups including -OH, -CH, C = O, COO-, C-O-C, and = C-H), Raman spectroscopy (with bands at 1369cm-1 (D-Band) and 1550cm-1 (G-Band), and an intensity ratio (ID/IG) = 0.88, indicating structural defects correlated with the sp3 hybridization sites on the TBCDs), XRD analysis (indicating an amorphous nature of particles), HRTEM imaging (showing homogeneous dispersal of TBCDs with typical sizes ranging from 2 to 10nm), FESEM analysis (showing a flat surface and minuscule particles), and Zeta potential analysis (revealing a surface charge peak at -51.0mV). Our adsorption experiments yielded significant results, with a substantial 50.1 % removal rate and an impressive adsorption capacity of 735.2mg g-1. Theoretical adsorption parameters were rigorously analyzed to understand the adsorption behavior, surface interactions, and mechanisms. Among these models, the Langmuir isotherm in conjunction with pseudo-second-order kinetics provided an exceptional fit (with R2 values closer to 1) for our system. The Gibbs free energy (ΔG) was found to be negative at all temperatures, indicating the spontaneity of the reaction. Regarding mechanism, electrostatic attraction ((+ve) MB dye + (- ve) TBCDs), π-π stacking adsorption facilitated by the graphitic structure, formation of multiple hydrogen bonds due to polar functional groups, and a pore-filling mechanism wherein the cationic MB dye fills the pores of TBCDs with graphene oxide layers, forming an adduct were identified. Furthermore, we demonstrated the regenerative capacity of our system by effectively extracting and recovering the MB dye (with a regeneration rate of 77.1%), utilizing ethyl alcohol as the solvent. These findings not only provide valuable insights into the adsorption capabilities of TBCDs but also highlight the potential of our approach in the recovery of expensive cationic organic dye compounds from polluted environments.

Comprehensive investigations into the synergy of S-scheme heterojunction between nitrogen-doped ZnO nano-rods and g-C3N4 nanosheets for improved photocatalytic degradation

In this work, N-ZnO nanorods decorated with 2D g-C3N4 prepared by hydrothermal synthesis are studied for their synergistic effect in regard to enhanced photocatalytic activity. The synthesized material is characterized with XRD, FESEM, EDX, TEM and HR-TEM to perform the structural, morphological and elemental analysis along with XPS and FTIR for tracking sample purity and to study the elemental composition on the surface of the material; UV–Visible spectroscopy and PL spectroscopy for investigating the optical properties, bandgap calculation and to inquire about the defects in the structure. N-ZnO/g-C3N4 shows remarkable photocatalytic MB degradation ability upon solar irradiation which is 2.8 and 1.2 times exceeds than pristine ZnO and g-C3N4, attributed to the s-scheme mechanism for charge migration. The construction of s-scheme heterojunction among N-ZnO and g-C3N4 generates an internal electric field that saliently promotes charge separation at the interface. Furthermore, post-stability test for 8 cycles with XRD and FTIR analysis to verify the material integrity is presented. The scavenger experiments revealed the involved active species. This research does seem to pique interest in the creation of cutting-edge photocatalysts that utilize the solar spectrum to remove harmful organic dyes from water.

Enhancing photocatalytic performance through surfactant-assisted electrochemical synthesis: Surface modification of hierarchical ZnO morphologies with Ag/ZnWO4 nanoparticles

This study presents the synthesis of surface-decorated CTAB-capped ZnO nanoparticles doped with Ag/ZnWO4 through a surfactant-assisted electrochemical synthesis approach. The development of surface-decorated composites is of considerable interest for enhancing photocatalytic efficiency. We report the synthesis of pristine, binary, and surface-decorated ZnO catalysts, specifically Zn, Zn/Ag, Zn/ZnWO4, and Zn/Ag/ZnWO4. Various methods for physicochemical characterization have been utilized to verify the catalysts' structural, optical, and morphological properties. The results demonstrate the successful surfactant capping and metal doping. The synthesized nanoparticles have been tested for their photocatalytic performance against Malachite Green, an environmentally harmful organic dye, across various reaction conditions. Scavenger studies reveal that the photodegradation process is primarily driven by superoxide and hydroxyl radicals and, to a lesser extent, by photogenerated holes. The decrease in electron-hole pair recombination in the Zn/Ag/ZnWO4 photocatalyst results in an enhanced degradation of Malachite Green when exposed to visible light.

Enhanced photocatalytic removal of tetracycline and methyl orange using Ta3N5@ZnIn2S4 nanocomposites

The presence of toxic substances in wastewater poses a severe threat to human survival and development. In recent years, photocatalytic technology has emerged as a promising solution for the efficient removal of harmful pharmaceutical pollutants and organic dyes. This study focuses on the synthesis and characterization of a novel Ta3N5@ZnIn2S4 (TN@ZIS) nanocomposite, which exhibits remarkable photocatalytic performance in degrading tetracycline hydrochloride (TC) and methyl orange (MO) under LED irradiation. The TN@ZIS nanocomposite was synthesized using a simple route involving flux-assisted nitridation and in-situ hydrothermal treatment processes. The resulting structure consists of layered ZnIn2S4 nanosheets firmly anchored onto the surface of Ta3N5 nanorods, as confirmed by SEM and TEM analysis. XPS tests revealed a strong interfacial interaction within the nanocomposite, which is advantageous for the separation of photogenerated charge carriers. Notably, the TN@ZIS hybrids demonstrated a significant improvement in photocatalytic activity compared to bare Ta3N5 nanorods. During the entire photocatalytic degradation process (60 min and 100 min), TC and MO achieved degradation efficiencies of approximately 72.3 % and 81.2 %, respectively. These results highlight the competitive nature of TN@ZIS among Ta3N5-based materials. The enhanced photocatalytic performance can be primarily attributed to the synergistic effect of improved separation of photogenerated charge carriers and the increased active sites provided by the TN@ZIS nanocomposite. This study contributes to the development of efficient and stable photocatalysts for the removal of pharmaceutical pollutants and organic dyes from wastewater, thereby addressing the urgent need for effective water treatment technologies.

Eco-Friendly Synthesis of Alstonia scholaris (L.) R. Br. Extract-Mediated Nanostructured Material: Removal of Organic Pollutants from Water Resources

In this modern era, pollution of water resources due to industrial waste effluents is an alarming problem as it can cause various health problems in aquatic animals as well as in humans. Among the industrial pollutants, organic dyes are one of the leading chemicals that cause severe damage to the aquatic environment. These harmful organic dyes are practically omnipresent in various types of industries such as textile, tannery, cosmetic, food industries, etc. Photodegradation of these organic dyes is regarded as a promising technology for industrial waste treatment as it is a cost-effective and environment-friendly process. In this study, a nanostructured material of iron has been synthesized using the Alstonia scholaris (L.) R. Br. extract in an easy and eco-friendly way. The potential of this synthesized nanostructured material to act as a photocatalyst, for the degradation of organic dyes, has been explored. Due to its small size and high dispersion, more than 72 % degradation has been achieved within 90 min. A comparative study of its photocatalytic efficiency in different degradation processes has also been performed.

Utilization of a trinuclear Cu-pyrazolate inorganic motif to build multifunctional MOFs.

The current work aims to generate multifunctional MOFs by incorporating a well-known inorganic motif, a trinuclear Cu-pyrazolate [Cu3(μ3-OH)(μ-Pyz)3] (T-CuP) unit, as a node of the network. Accordingly, we report herein the synthesis and properties of five new compounds using five V-shaped dicarboxylic acids as auxiliary ligands. The structural features are consistent with the theme of grafting T-CuP units as nodal points of architectures whose chassis are primarily made of bent acids. V-shaped acids also induce a helical nature inside resulting frameworks. Beside their structural and physical features, T-CuP unit-based MOFs also vindicate our thematic approach of the trinuclear Cu-pyrazolate unit imparting specific physicochemical properties, such as magnetic, electrical, and catalytic properties, to resultant MOFs. The MOFs show excellent catalytic properties in reducing 4-nitrophenol, which could be attributed to the porous nature of the network along with the presence of metal centres with unsaturated coordination within the T-CuP unit. Furthermore, efficient photocatalytic degradation of harmful organic dyes confirms their importance for environmental remediation. The presence of a T-CuP unit and various functional groups also make some of the MOFs suitable candidates for electrical applications, which is indeed manifested in encouraging proton conductivity. Finally, the potential of current MOFs, fitted with a magnetically important trinuclear Cu-pyrazolate motif, as magnetic materials has also been thoroughly investigated.

Development of environmentally friendly catalyst Ag-ZnO@cellulose acetate derived from discarded cigarette butts for reduction of organic dyes and its antibacterial applications

The release of harmful organic dyes from different industries besides its degradation products is a major contributor to environmental contamination. The catalytic reduction of these organic pollutants using nanocomposites based on polymeric material presents potential advantages for the environment. In this study, novel nanocomposite based on cellulose acetate (CA)-derived from discharged cigarette butts and zinc oxide nanoparticles (ZnO NPs) was prepared utilizing a very simple and low-cost solution blending method and used as support for silver nanoparticles (Ag NPs). A simple reduction method was used to anchor different percentages of Ag NPs on the ZnO@CA nanocomposite surface via utilizing sodium borohydride as a reducing agent. The Ag-ZnO@CA nanocomposite was characterized using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy. The TEM analysis showed spherical Ag NPs, with an average diameter of ∼17.6 nm, were uniformly anchored on the ZnO@CA nanocomposite surface. The prepared nanocomposites were evaluated as catalysts for the reduction of organic dyes in water. It was found that 10 % Ag-ZnO@CA nanocomposite showed a remarkable reduction of Rhodamine B (RhB), Rhodamine 6G (Rh6G), Methylene Blue (MB), and Sunset Yellow (SY) dyes in short time. In the presence of this nanocomposite, the rate constant, kapp values for RhB, Rh6G, MB, and SY were 0.3498 min−1, 1.51 min−1, 0.2292 min−1, and 0.733 min−1, respectively. This nanocomposite was recovered and reused in five successive cycles, with a negligible loss of its activity. Furthermore, the nanocomposites demonstrated moderate antibacterial activity toward Staphylococcus aureus and Escherichia coli. Thus, this study directed attention on recycling of waste material to a valuable nanocomposite and its applications in environmental protection.

Evaluation of biosynthesized GO@CeO2 nanocomposites as a catalyst for UV-assisted degradation of organic dyes and phytotoxicity studies

The availability of clean water for human use is one of the world's most pressing problems, and scientists are working hard to find a solution. Water that has been treated using nanotechnology is free of harmful microbes and organic dyes, making it superior to older treatment techniques. This research investigated the effects of light on graphene oxide nanocomposites infused with biosynthesized CeO2 nanoparticles. Numerous techniques were applied to characterize the as-prepared nanocomposites, including HRTEM, FTIR, XRD, XPS, UV-Vis, and Raman spectroscopy. Adsorbing and photodegrading CV, MB, and AO from an aqueous solution was accomplished with the help of a GO@CeO2 nanocomposite. Adsorption and photodegradation of the GO@CeO2 nanocomposite occur significantly more rapidly and efficiently in the presence of visible light than in the absence of light. The GO@CeO2 compound was able to eliminate 85 % of CV, 91.81 % of MB, and 87 % of AO in under 90 min. Adsorption alone is ineffective against CV, MB, and AO, but photodegradation in visible light is superior. According to the results of a research study with fenugreek plants, the treated effluents do not have any phytotoxic effects. Degradation of organic dyes in industrial wastewater using the GO@CeO2 catalyst was proven to be an efficient and inexpensive method.

Application of Molybdenum Disulfide Nanomaterials in Wastewater Treatment

The problem of global water pollution is becoming increasingly serious, especially in industrial wastewater from industries such as textiles and printing, which contains a large amount of toxic and harmful organic dyes, causing serious water pollution problems. It is urgent to remove organic dyes from wastewater and improve the quality of water resources. In wastewater treatment, adsorption is considered the most convenient, economical, and efficient method for treating dye wastewater, and can be used in large-scale production. Molybdenum disulfide nanomaterials have attracted the attention of researchers, especially in the field of wastewater treatment, due to their unique physical, chemical, electrical, biological, and mechanical properties.

Green synthesis of iron oxide nanoparticles using brown Egyptian propolis extract for evaluation of their antibacterial activity and degradation of dyes

Metal oxide nanoparticles have been widely used in antimicrobial agents, anticancer drugs, wastewater treatment, degradation of harmful organic dyes, and other fields. In this study, iron oxide nanoparticles (IONPs) were synthesized using Brown Egyptian Propolis (BEP) extract as a reducing and stabilizing agent. The synthesized BEP-IONPs were then applied for their antibacterial activity and to remove cationic methylene blue (MB) dye from an aqueous solution. The chemical structural, morphological and optical properties of the synthesized BEP-IONPs were characterized using UV-visible spectroscopy, FTIR, XRD, XPS, SEM, TEM, and EDX. GC-MS analysis was carried out to study the chemical composition of the BEP extract. The BEP-IONPs prepared with a ratio of 1:1 and 1:2 (BEP:FeCl3) were found to be spherical, with average particle sizes of around 87 and 194 nm, respectively. The antibacterial activity was tested on gram-negative and gram-positive bacterial strains, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis. The results showed that the synthesized BEP-IONPs have potent antibacterial activity with a zone of inhibition of 23.5 mm for Pseudomonas aeruginosa gram-negative bacteria, and a high MB dye adsorption capacity of up to 92.7% at 210 min. The kinetics of photocatalytic degradation of MB dye by BEP-IONPs was found to follow pseudo-first-order kinetics, with a constant rate of 0.0178 min-1. Finally, the synthesized BEP-IONPs can be used effectively as antimicrobial agents against human pathogens and as photocatalysts for the removal of harmful organic dyes.

The performance of carboxylated alginic acid derivatives via methyl orange and Congo red catalytic reduction

Numerous water-treatment marital have been developed during the past few years, including adsorbents., the catalytic reduction behavior of carboxylated alginic acid derivatives has been investigated against harmful organic dyes including Methyl Orange (MO) and Congo Red (CR). Alginic acid was firstly oxidized through an easy addition of KMnO4 as an oxidizing agent. A carboxylated alginic acid (CAA) has been interacted with selected metal ions (Sn, Fe, Ni, and Zr) through coordination bonds at the value of pH = 4 to form the corresponding metal complexes namely: Sn-CAA, Fe-CAA, Ni-CAA, and Zr-CAA. The consistency of the coordination was confirmed by several spectroscopic techniques including FT-IR, XRD, SEM, and EDX. The catalytic reduction of these metal ion-based products was carried out against MO, and CR in the presence of NaBH4 as a reducing agent under UV irradiation. All catalysts-based metal complexes showed enhanced catalytic reduction against CR compared to MO. Among all those mentioned metal complexes Sn-CAA showed the best catalytic reduction of these dyes. The time is taken by the Sn-CAA for CR, and MO is 5 and 7 min respectively. Ni-CAA was classified as the second efficient product against both dyes, where the reduction process took 20 and 9 min respectively. The other two catalysts took a long time for CR and MO reduction. Zr-CAA showed more than 80% reduction of only CR dye within 20 min. Whereas, Fe-CAA did not show any significant sign of reduction against both the dyes after the same time. The order of higher catalytic reduction was illustrated as: Sn-CAA > Ni-CAA > Zr-CAA = Fe-CAA.

Characteristics of nano-sized composites based on rare earth orthoferrites and hematite

Photocatalysts based on orthoferrites of rare earth elements are used to neutralize a number of harmful substances and organic dyes under the influence of visible light, which makes them to promise the introduction of resource-saving water purification technologies. The thermal-gravimetric analysis, X-ray phase analysis, scanning electron microscopy, and energy-dispersive spectroscopy was used to study nanoscale samples of orthoferrites of rare earth elements and hematite obtained by the chemical precipitation of aqueous solutions of inorganic salts of ferrum with lanthanides (La, Er, Sm, Dy, Nd, Yb ) and Y in a weakly alkaline environment and subsequent heat treatment of sediments at 800 and 1100 °C. It was found that during the simultaneous precipitation of hydroxide phases of ferrum and REE, their transformation under the influence of temperature is spatially separated due to the differences in the temperatures of phase transformations and the hydrogen index of the precipitation of precursor phases. It is shown that, depending on the chemical composition of the initial solutions, goethite is formed in the temperature range of 190-250 °C, and the formation of hematite takes place at 425-450 °C. Dehydroxylation of lanthanum hydroxide is observed at 300-330 °С, and the formation of lanthanum oxides continues in the range from 390 to 900 °С. The perovskite phase crystallizes at 960 °C. Using the X-ray phase analysis method, it was established that hematite and a mixture of REE oxygen phases are present in the sediments heat-treated at 800 °C. At 1100 °C, the structure of perovskite and hematite with particle sizes from 25 to 40 nm was identified in the composition of the powders. It was determined that the removal of auxiliary substances takes place at temperatures of 650-770 °C and no impurities of K, Na, S, Cl, or C in the powders fired at 1100 °C. Hematite and perovskite particles are well crystallized and form fragile aggregates, the specific surface area of the samples is several m2/h.

Ni-coordination polymer as potential remedial compound for efficient detection and seclusion of toxic aromatic dyes from contaminated water

A parqueted 2D metal-organic framework [Ni(HBTC)(Bimb)]n(1) has been synthesized hydrothermally by means of Ni(II) ion with Benzene 1,3,5 tricarboxylic acid (BTC), 1,4-bis(imidazole-1-ylmethyl)benzene (Bimb) ligands. The (1) was employed as adsorbent for a series of 13 harmful organic dyes in contaminated water. The adsorption study shows that it exhibits good efficiency for cationic dyes like Methyl Violet (93.0%), Crystal Violet (92.0%),), Rhodamine B (87%), Rhodamine 6G (89.0%) and for Rose Bengal it is 90.0%, which is an anionic dye while for neutral dye i.e., Neutral Red it is 87.0% at ambient temperature and found that electrostatic attractions, π–π and H-bonding interactions are instrumental in dye uptake. The effect of pH was analyised and found that as pH increases the adsorption efficiency of Ni-coordination polymer increased exponentially. It shows maximum adsorption concentration than Rice husk (RH) and Saw dust (SD) for maximum dyes among all the 13 screened dyes. The detection limit of (1) for mostly adsorbed concentration of dyes, namely MV, CV, RB, NR, RhB and Rh6G, was found to be 0.70 ppm, 0.87 ppm, 1.06 ppm, 1.33 ppm, 1.34 ppm and 1.36 ppm, respectively and follows pseudo-first (MV, CV and RB) and pseudo-second (NR, RhB and Rh6G) order kinetics. The excellent adsorption and regeneration concert of (1) summit to be a potential and efficient future remedial material for detection and separation of toxic dyes from waste water contaminated by industrial effluents.

Green Synthesis of Iron Oxide Nanoparticles Using Psidium guajava L. Leaves Extract for Degradation of Organic Dyes and Anti-microbial Applications

Among various metal and metal oxide nanoparticles, iron-oxide nanoparticles (IONPs) have been more widely used for the degradation of harmful organic dyes and the inhibition of microbial growth; on the other hand, it positively affects mammalian cells. Green synthesis of IONPs has piqued the interest of researchers because it improves stability and is an environmentally friendly method of avoiding the use of harmful chemicals as a reducing agent. In this study, IONPs were synthesized using Psidium guajava leaf extract, which was further applied for its industrial dye degradation and anti-microbial activities. UV–visible spectroscopy, FTIR, XRD, XPS, EDX, FE-SEM, HR-TEM, and Zeta potential analysis were used to characterize the synthesized nanoparticles. The synthesized IONPs managed to degrade methylene blue (MB) and methyl orange (MO) in the presence of H2O2. The degradation efficiency was 82.1% in 95 min and 53.9% in 205 min for MB and MO, respectively. Likewise, the synthesized IONPs showed good anti-bacterial activity with a ZOI of 13 mm for both Shigella sonnei and Staphylococcus aureus gram-positive bacteria. Similarly, they demonstrated good anti-fungal activity with ZOI of 15 mm and 13 mm for Candida tropicalis and Candidaalbicans, respectively. Thus, the IONPs can combat harmful organic dyes, and they can terminate the pathogenicity of several human pathogens.

Construction, characterization, and photocatalytic study of La2Ti2O7/C3N4+xHy and La2Ti2O7/GO nanocomposites as efficient catalysts toward photodegradation of harmful organic dyes

Fabrication of highly active photocatalysts which could be utilized for water detoxification is an urgent matter. Herein, we synthesized nanoparticles of La2Ti2O7 which are decorated with graphene oxide and carbon nitride via a simple microwave method. The structure, crystallinity, and morphology were determined to understand the physicochemical nature of the photocatalysts. The effect of pivotal parameters such as the amount of photocatalyst, dye concentration, and initial pH on degradation of methylen orang, methylene blue and rhodamine B, were examined under direct visible light irradiation. The prepared photocatalysts showed excellent photocatalytic activity with remarkable stability and recyclability without major loss of activity in the successive cycles. The results illustrate that the photocatalytic efficiency of graphene oxide and carbon nitride was enhanced by the addition of La2Ti2O7. These results indicate that the aforementioned nanocomposites are effective in degradation of dyes from wastewater and could be applied for large-scale industrial utilization in the future.

Highly efficient and rapid purification of organic dye wastewater using lignin-derived hierarchical porous carbon

Coating manufacturing, textile processing, and plastic industry have led to dramatical release levels of hazardous organic dye pollutants threatening public health and the environment. To solve this problem, porous carbon materials are being developed following with the United Nations initiative on water purification. However, conventional porous carbon materials face many challenges, such as limited removal rates, low adsorption capacity, and high chemicals consumption, hampering their large-scale utilization in dye wastewater treatment. Herein, we demonstrate a high-performance lignin-derived hierarchical porous carbon (LHPC) material directly prepared from renewable lignin through a low-cost activation procedure. The large specific surface area (1824 m2/g) enables the rapid and effective adsorption of organic dyes. Therefore, the LHPC exhibits an ultrahigh adsorption ability (1980.63 mg/g) and removal rate (99.03% in 10 min) for Azure B, superior to that of other adsorbents. Additionally, the LHPC adsorbent, organic dyes, eluting agent, and water all can be recycled and reused in a designed close-looped system. Its high removal ability and rate, strong retrievability, low-cost and scalable production combined with high dyes adsorption universality, positions our LHPC as a promising commercial adsorbent candidate for the purification of harmful organic dye wastewater, especially for heavily polluted area with an insistent demand for clear water.