Efficient Organic Dye Research Articles

Eco-friendly fabrication of ZnO-TiO2-rGO nanocomposite for efficient adsorption-assisted organic dyes elimination

The growing interest in combining the photocatalytic properties of semiconductors like ZnO and TiO2 with the superior electron conduction capabilities of graphene has resulted in the successful synthesis of in-situ reduced graphene oxide (rGO) supported ZnO-TiO2 nanostructures through a simple microwave-assisted synthesis method. X-ray Diffraction Spectroscopy (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–visible spectroscopy (UV–vis), and Fourier Transform Infrared Spectroscopy (FTIR) were employed to characterize structural, morphological and optical properties as well as surface functional groups of the synthesized products. The XRD measurements of our synthesized samples confirm both structural crystallinity and phase purity, while the FTIR analysis verifies the complete reduction of graphene oxide (GO) to reduced graphene oxide (rGO). The synthesized ternary nanocomposite ZnO-TiO2-rGO exhibited a remarkable 100 % adsorption-assisted removal efficiency for 20 mg/L methylene blue (MB) dye under ultraviolet light illumination within 120 min, along with a 56 % dye adsorption removal efficiency in the same time interval. In comparison, pure ZnO showed 0 % adsorption and only 31 % photocatalytic efficiency at the similar condition. Remarkably, the ZnO-TiO2-rGO nanocomposite exhibited exceptional photocatalytic activity mediated by adsorption, achieving complete degradation of MB dye within 5 min under sunlight irradiation. The photocatalytic efficiency and dye adsorption capacity were found to be significantly lower for the anionic dye methyl orange (MO) compared to the cationic MB dye. The study thoroughly investigated the influence of catalyst dose and initial dye concentration on photodegradation. The proposed mechanism indicates that the extensive surface area and numerous active sites on the rGO promote adsorption, which is then followed by degradation through the metal oxides. Overall, the results unveil that the microwave-assisted synthesis of ZnO-TiO2-rGO nanocomposite is a promising and environmentally friendly approach for efficiently degrading dyes from contaminated wastewater using both UV light and natural sunlight irradiation.

Experimental and Theoretical Studies on the Adsorption of Bromocresol Green from Aqueous Solution Using Cucumber Straw Biochar

Biochar prepared from crop straw is an economical method for adsorbing bromocresol green (BCG) from textile industrial wastewater. However, there is limited research on the adsorption mechanism of biochar for the removal of BCG. This study utilized cucumber straw as raw material to prepare biochar with good adsorption potential and characterized its physicochemical properties. Through adsorption experiments, the effects of solution pH, biochar dosage, and initial dye concentration on adsorption performance were examined. The adsorption mechanism of cucumber straw biochar (CBC) for BCG was elucidated at the molecular level using adsorption kinetics, adsorption isotherm models, and density functional theory (DFT) calculations. Results show that the specific surface area of the CBC is 101.58 m2/g, and it has a high degree of carbonization, similar to the structure of graphite crystals. The presence of aromatic rings, –OH groups, and –COOH groups in CBC provides abundant adsorption sites for BCG. The adsorption process of CBC for BCG is influenced by both physical and chemical adsorption, and can be described by the Langmuir isotherm model, indicating a monolayer adsorption process. The theoretical maximum monolayer adsorption capacity (qm) of BCG at 298 K was calculated to be 99.18 mg/g. DFT calculations reveal interactions between BCG and CBC involving electrostatic interactions, van der Waals forces, halogen–π interactions, π–π interactions, and hydrogen bonds. Additionally, the interaction of hydrogen bonds between BCG and the –COOH group of biochar is stronger than that between BCG and the –OH group. These findings provide valuable insights into the preparation and application of efficient organic dye adsorbents.

Lignocellulosic materials extraction from waste baby diaper to prepare light-responsive metal oxide/carbon composite for efficient organic dye pollutant removal

The bimetal oxide comprising nickel incorporated β-Bi2O3 on graphitic carbon in the form of bismuth nickel oxide (BNO@C) was prepared by waste lignocellulosic materials collected from cheap and readily available baby diapers. The prepared BNO@C was used to photocatalytically degrade methylene blue under UV-light irradiation. Prior to the photocatalytic performance analysis, the formation of BNO@C was confirmed by various morphological and structural analysis including SEM, TEM, XRD, and XPS analyses. As a result, the two-dimensional nanosheet morphology and tetragonal primitive lattice-structure with 2+ and 3+ oxidation stated Ni and Bi in BNO@C structural formulation were confirmed. In photocatalysis experimentation examined with BNO@C, the maximum methylene blue removal percentage of 96.7 % was achieved within 16 min. The influence of Ni2+ in BNO@C was identified by performing the photocatalytic performance of bare NiO@C and Bi2O3@C, yielding maximum dye removal of 32.8 % and 64.5 %, respectively. The efficacy of Ni in BNO@C toward increasing catalytic efficiency was identified using DFT analysis, revealing the acting of Ni as active sites for improved light absorption tendency. These findings show a novel strategy to prepare a low-cost BNO@C catalyst with efficient photocatalytic activity, opening a new path for a cost-efficient wastewater treatment approach.

Molecular Engineering Strategies of Spectral Matching and Structure Optimization for Efficient Metal-Free Organic Dyes in Dye-Sensitized Solar Cells: A Theoretical Study.

Metal-free organic dyes are promising dyes that can be applied widely in dye-sensitized solar cells (DSSCs). The rational design and selection of dyes with complementary absorption can promote the development of methods that can enhance the utilization of incident light by DSSCs, such as cosensitization and tandem devices. Based on these opinions, the structure of the reported high-performance metal-free organic dye ZL003 is used as a template to design two new metal-free organic dyes, HX-1 and HX-2, by replacing its donor unit with a 2-phenothiazine-phenylamine unit and fusing its three independent π-bridge units into a whole with the aim of driving the red shift and the blue shift of the absorption spectra of ZL003, respectively. Through theoretical investigation, it is demonstrated that the perfect complementary optical absorption of HX-1 and HX-2 can be realized as the shift of the absorption spectra of ZL003 to different directions, which means their feasibility to the application in cosensitization or tandem dye-sensitized solar cells (T-DSSCs). Furthermore, it is hypothesized that HX-1 may be the dye with better photovoltaic performance than ZL003 by modeling their intramolecular charge-transfer (ICT) processes, TiO2 surface adsorption, and photovoltaic parameters. The short-circuit current density (Jsc) and photoelectric conversion efficiency (PCE) of HX-1 are 23.10 mA·cm-2 and 21.26% in theory, compared to those of 20.68 mA·cm-2 and 19.64% in ZL003 at the same computational level, respectively. In view of the complementary optical properties, the combination of HX-1 with HX-2 may be a reasonable option for dyes for the development of a highly efficient cosensitization system or T-DSSCs in the future. In terms of such findings, these two novel metal-free organic dyes may have bright prospects in the research of highly efficient DSSCs, and this work can provide a reference for the design of dyes with complementary absorption through simple structural adjustments of the realistic dyes with high photovoltaic performance.

Novel Biomaterial-Derived Activated Carbon from Lippia Adoensis (Var. Koseret) Leaf for Efficient Organic Pollutant Dye Removal from Water Solution

Today, various pollutants, such as dyes from industries, are being released into the environment worldwide, posing significant challenges that require sustainable attention and advanced solutions. This research focuses on the synthesis and characterization of a novel biomaterial-based activated carbon (AC) derived from Lippia Adoensis (Koseret) leaves and investigates its effectiveness in removing MB from aqueous solutions. The biomaterial adsorbent derived from LA was subjected to proximate analysis, pH-point zero charge (pHpzc), FT-IR, and SEM characterization. The pHpzc results indicated a slightly acidic surface functional group for AC. The impact of temperature and chemical impregnation (H<sub>3</sub>PO<sub>4</sub>, NaCl and NaOH) was examined, with the optimal temperature of AC preparation found to be 600°C. The use of H<sub>3</sub>PO<sub>4</sub> for the chemical activation of biomaterials resulted in a high AC surface area. Batch adsorption experiments involved varying pH (2–10), dosage (0.1–0.35 g/50ml), initial concentration (10–35 ppm) and contact time (15–105 min). The optimal parameters were determined as pH = 8, dose = 0.25g, concentration = 10 ppm, and contact time = 75 min. The maximum adsorption capacity and removal efficiency were calculated as 3.99 and 92.2%, respectively. Thermodynamic analysis confirmed the spontaneous and endothermic nature of the system. Adsorption isotherm and kinetic studies revealed a good fit with the Langmuir isotherm (R<sup>2</sup>= 0.999), indicating monolayer adsorption and the pseudo-second order model, respectively. These findings suggest that the use of LA-AC could offer a cost-effective solution for the removal of methylene blue from water, contributing to the solution of water pollution challenges and promoting the adoption of eco-friendly wastewater treatment technologies.

Third-Generation Anticancer Photodynamic Therapy Systems Based on Star-like Anionic Polyacrylamide Polymer, Gold Nanoparticles, and Temoporfin Photosensitizer.

Photodynamic therapy (PDT) is a non-invasive anticancer treatment that uses special photosensitizer molecules (PS) to generate singlet oxygen and other reactive oxygen species (ROS) in a tissue under excitation with red or infrared light. Though the method has been known for decades, it has become more popular recently with the development of new efficient organic dyes and LED light sources. Here we introduce a ternary nanocomposite: water-soluble star-like polymer/gold nanoparticles (AuNP)/temoporfin PS, which can be considered as a third-generation PDT system. AuNPs were synthesized in situ inside the polymer molecules, and the latter were then loaded with PS molecules in an aqueous solution. The applied method of synthesis allows precise control of the size and architecture of polymer nanoparticles as well as the concentration of the components. Dynamic light scattering confirmed the formation of isolated particles (120 nm diameter) with AuNPs and PS molecules incorporated inside the polymer shell. Absorption and photoluminescence spectroscopies revealed optimal concentrations of the components that can simultaneously reduce the side effects of dark toxicity and enhance singlet oxygen generation to increase cancer cell mortality. Here, we report on the optical properties of the system and detailed mechanisms of the observed enhancement of the phototherapeutic effect. Combinations of organic dyes with gold nanoparticles allow significant enhancement of the effect of ROS generation due to surface plasmonic resonance in the latter, while the application of a biocompatible star-like polymer vehicle with a dextran core and anionic polyacrylamide arms allows better local integration of the components and targeted delivery of the PS molecules to cancer cells. In this study, we demonstrate, as proof of concept, a successful application of the developed PDT system for in vitro treatment of triple-negative breast cancer cells under irradiation with a low-power LED lamp (660 nm). We consider the developed nanocomposite to be a promising PDT system for application to other types of cancer.

Three-dimensional porous bimetallic metal–organic framework/gelatin aerogels: A readily recyclable peroxymonosulfate activator for efficient and continuous organic dye removal

Three-dimensional porous bimetallic metal–organic framework/gelatin aerogels: A readily recyclable peroxymonosulfate activator for efficient and continuous organic dye removal

Screening efficient organic dyes based on ZL001 by modulating its auxiliary electron acceptor for dye-sensitized solar cells: A theoretical perspective

Based on ZL001 dye, in this work a series of novel organic dyes (denoted M1-M9) were designed by modulating its auxiliary electron acceptors, and then their electronic, optical, and photovoltaic properties were systematically estimated by density functional theory (DFT)/time-dependent DFT (TD-DFT) calculations coupled with Marcus charge transfer model. Results showed that the modulation of auxiliary electron acceptor can efficiently dominate the HOMO-LUMO gap, and dramatically enhance the optical absorption. By exactly estimating the influence of electron injection/recombination on the photocurrent density, the power conversion efficiency (PCE) for ZL001 was estimated to be about 12.90 % with Voc=837 mV, Jsc=21.92 mA·cm−2, and FF= 0.703 at the standard solar radiation, which is in good agreement with its measured value of 12.8 ± 0.1 % (Voc=887±6 mV, Jsc=20.57±0.18 mA·cm−2, and FF= 0.700±0.004). With the same scheme, the predicted PCE value for most of designed dyes was higher than that of ZL001, illuminating that our molecular design is successful. In comparison with ZL001, three newly designed dyes (M7, M8, and M9) with thieno[3,4-b] pyrazine (TPZ), 2,5-dimethyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP), and 5,5′-bithieno[3,4-b]pyrazine (BPZ) as the auxiliary electron acceptor exhibit high PCE values of 19.45 %, 17.63 % and 24.64 % respectively at the AM1.5 G conditions, suggesting that these three dyes are promising candidates for solar cell applications.

Urchin-like CO2-responsive magnetic microspheres for highly efficient organic dye removal

CO2-responsive materials have emerged as promising adsorbents for the remediation of refractory organic dyes-contaminated wastewater without the formation of byproducts or causing secondary pollution. However, realizing the simultaneous adsorption−separation or complete removal of both anionic and cationic dyes, as well as achieving deeper insights into their adsorption mechanism, still remains a challenge for most reported CO2-responsive materials. Herein, a novel type of urchin-like CO2-responsive Fe3O4 microspheres (U-Fe3O4 @P) has been successfully fabricated to enable ultrafast, selective, and reversible adsorption of anionic dyes by utilizing CO2 as a triggering gas. Meanwhile, the CO2-responsive U-Fe3O4 @P microspheres exhibit the capability to initiate Fenton degradation of non-adsorbable cationic dyes. Our findings reveal exceptionally rapid adsorption equilibrium, achieved within a mere 5 min, and an outstanding maximum adsorption capacity of 561.2 mg g−1 for anionic dye methyl orange upon CO2 stimulation. Moreover, 99.8% of cationic dye methylene blue can be effectively degraded through the Fenton reaction. Furthermore, the long-term unresolved interaction mechanism of organic dyes with CO2-responsive materials is deciphered through a comprehensive experimental and theoretical study by density functional theory. This work provides a novel paradigm and guidance for designing next-generation eco-friendly CO2-responsive materials for highly efficient purification of complex dye-contaminated wastewater in environmental engineering.

Smart nanocomposites: Harnessing magnetically recoverable MWCNT-CF for efficient organic dyes reduction in water quality monitoring applications

The accelerating use of organic dyes in various industries has led to a surge in water pollution, especially from non-biodegradable dye effluents discharged into water resources. This study addresses the critical issue of catalyzing the reduction of two prevalent dyes, methylene blue (MB) and rhodamine-B (RhB), using a multiwalled carbon nanotube-cobalt ferrite (MWCNT-CF) nanocomposite. The synthesized nanocomposite demonstrates exceptional catalytic activity, stability, and recyclability. Conventional methods for treating dye-containing wastewater often prove expensive. This study explores the efficacy of catalytic reduction, a relatively fast process facilitated by semiconductor nanoparticles. Structural analyses using X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) confirm the formation of the nanocomposite, revealing unsaturated surface bonds and chains conducive to adsorption. The nanocomposite exhibits a remarkable reduction in both dyes, with easy recyclability for multiple cycles. Magnetization studies confirm the ferrimagnetic nature of the nanocomposite, facilitating its efficient separation from the reaction mixture using a magnet. The study delves into the kinetics of the catalytic reduction following pseudo-first-order kinetics. The surface modifications of the nanocomposite, as revealed by TEM, contribute to enhanced adsorption and catalytic efficiency. Notably, the MWCNT-CF nanocomposite demonstrates negligible loss of catalytic activity during recycling, highlighting its potential for cost-effective and sustainable applications in dye reduction across various industries.

Screening novel XY1b-based organic dyes by modifying electron-assisted acceptors for dye-sensitised solar cells: a theoretical analysis

To screen efficient organic dyes, six novel XY1b-based molecules are designed by modifying electron-assisted acceptors, and their electronic structure, optical properties and photovoltaic performances are evaluated in detail with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations coupled with the incoherent charge transfer model. Results show that benzoselenadiazole (BSD) and diketopyrrolopyrrole (DPP) are two best electron-assisted acceptors and replacing benzothiadiazole (BTD) with the BSD/DPP unit can redshift the maximum absorption peak by 13/67 nm. According to our estimation, the overall photoelectric conversion efficiency (PCE) of XY1b is as high as 13.09% with a J sc of 16.261 mA·cm−2, V oc of 1.047 V and FF of 0.769, in good agreement with its measured value of 11.8 ± 0.2% (J sc = 15.26 ± 0.18 mA·cm−2, V oc = 1.01 ± 0.003 V and FF = 76.3 ± 0.2%), verifying that the scheme proposed by us is reliable. With the same procedure, the predicted PCE values for dyes 1, 2 and 5 reach up to 18.00%, 15.95% and 27.37% respectively, indicating that these three dyes are potential efficient sensitisers and are worthy of further study by experiments.

Novel three-dimensional fibrous covalent organic frameworks constructed via silver amalgam bridging for efficient organic dye adsorption and removal.

The construction of covalent organic frameworks (COFs) with unique structures has great significance in exploring the structure-function relationship and extending their potential applications. Fibrous COFs have demonstrated superior performance in specific application scenarios owing to the distinctive three-dimensional (3D) structure. Herein, we report a facile strategy for the fabrication of 3D COF nanofiber by exploiting silver amalgam as a bridging agent to assemble one-dimensional-extended PA-COF modules into a tubular structure. Dimensions of the obtained 3D COF nanofiber were predicted by DFT calculations, and the nanofiber was endowed with the merits of favorable uniformity and high stability. Due to the enhanced exposure of conjugatable binding sites for dye retention offered by the novel 3D architecture, the PA-COF nanofiber exhibits fast adsorption (within 5 min) and superior adsorption capacity to various organic dyes, e.g., 1717 mg g-1 for methylene blue (MB) and 978.3 mg g-1 for methyl orange (MO). Moreover, the PA-COF nanofiber shows excellent reusability in dye adsorption, which makes it a potential medium for removing dye pollutants from wastewater. This work presents an effective strategy to construct COF materials with unique architecture and potential prospects in the fields of separation and wastewater treatment.

Multi-crosslinked robust alginate/polyethyleneimine modified graphene aerogel for efficient organic dye removal

Polymer composite aerogel holds great promise for sewage treatment. Here, a novel triply crosslinked alginate/graphene aerogel for efficient organic dye removal was reported. The triple crosslinking of aerogel was realized firstly by the association between in-situ released Ca2+ ions and sodium alginate (SA). And the electrostatic attraction between polyethyleneimine-modified reduced graphene oxide (PEI-RGO) and the alginate chain provides an additional boost to crosslinking the aerogel. Moreover, the hydrogen bonding between PEI and SA also helps in achieving the crosslinking of the aerogel. Thus, the robust triply crosslinked alginate/graphene aerogel was obtained with using cost-effective precursors and a straightforward process. Additionally, the as-prepared aerogels were employed to remove the cationic dyes from wastewater. It was found that the porous alginate/graphene exhibited a strong affinity to methylene blue (MB) and neutral red (NR). The adsorption process of the aerogel towards MB was in accordance with the Langmuir isothermal model and pseudo-second-order model, and the maximum theoretical adsorption capacities were 1091.9 and 813.2 mg g−1, suggesting its potential application in sewage treatment.

Natural tea extract coated porous MOF nano/microparticles for highly enhanced and selective adsorption of cationic dyes from aqueous medium

A simple, sustainable method was developed for boosting the dye adsorption capability of porous metal organic frameworks (MOFs) by coating them with natural tea extract. Nano/microparticles of zinc-terephthalic acid (ZnTPA) MOFs exhibited only 40% rhodamine B (Rh B) dye adsorption. The dye adsorption capability was strongly enhanced (up to 95%) after coating with natural tea extract and highly selective cationic dye adsorption. The coating of multifunctional biomolecules onto the ZnTPA matrix was expected to facilitate strong intermolecular interaction between MOF surface and organic dyes, which contributed to strongly enhanced dye adsorption. ZnTPA/Tea MOFs not only exhibited enhanced dye adsorption but also showed high retention capability. The broader scope of tea extract coating methodology for cationic dye adsorption was also demonstrated using other MOFs matrix. The exhausted ZnTPA MOF was easily regenerated by sonication followed by re-dipping into tea extract. Tea extract coated ZnTPA MOFs was also used as column packing materials for removing cationic dyes by filtration. Thus, the present work reported a facile strategy for efficient cationic organic dyes removal from the aqueous medium.

Canola meal‐derived biochar for highly efficient dye removal and the impact of compression treatment on porous structure

AbstractBACKGROUNDThis study reported a canola meal‐based biochar adsorbent for highly efficient organic dyes removal. SEM, BET, Zeta‐potential and XPS etc. were employed to characterize the micro‐structure and chemical composition of the biochar, demonstrating the impact of compression treatment on its inner pore structure.RESULTSKOH‐activated carbonized canola meal‐compressed (KCCM‐C) showed a high specific surface area of up to 2135 m2 g−1 with an average pore size of 2.65 nm, which exhibited excellent adsorption capacity for both positively and negatively charged dyes with maximum values of 985 mg g−1 and 813 mg g−1 for methylene blue (MB) and methyl orange (MO) respectively, exceeding majority of the biochar adsorbents reported so far. The dye adsorption behavior was dominated by monolayer coverage with both physical adsorption and chemisorption. Langmuir isotherm model fitted well with the adsorption data, and the adsorption kinetic followed the pseudo‐second‐order model. Negative Gibbs free energy and positive enthalpy change indicated that the adsorption was a spontaneous endothermic process. XPS analysis indicated that the amino groups of proteins inside the canola meal as the active sites were oxidated by KOH prior to other components, while the compact structure of compressed canola meal was more conducive to the formation of uniform meso‐pores inside canola meal‐derived biochar improving its adsorption performance.CONCLUSIONSThis high‐quality porous biochar, directly synthesized from the compressed canola meal, simplifies the grinding process and presents a valuable opportunity for the value‐added application of canola meal. © 2023 Society of Chemical Industry (SCI).

Constructing a novel Ag2MoO4/MIL-101(Fe)/Ag composite for efficient crystal violet degradation via photo-Fenton-like process

This study presents a novel ternary Ag2MoO4/MIL-101(Fe)/Ag catalyst for efficient crystal violet (CV) degradation under visible light. Silver nanoparticles were in-situ generated on Ag2MoO4/MIL-101(Fe) through Ag2MoO4 reduction with NaBH4. Extensive characterization (XRD, FT-IR, FE-SEM, EDX, TEM, UV–Vis DRS, BET, PL spectroscopy) confirmed the catalyst's structure. The ternary composite exhibited significantly enhanced photo-Fenton catalytic activity, with reaction rates approximately 3.5 and 5 times faster than those observed with the Ag2MoO4/MIL-101(Fe) and pristine catalysts, respectively. Optimal conditions (H2O2 concentration of 50 mM, catalyst dosage of 2 g/L, pH 7, CV concentration of 25 mg/L, and temperature of 25 °C) were determined. Hydroxyl radicals dominated CV degradation, with minor contributions from electrons, holes, and superoxide radicals. The ternary composite showed excellent reusability, retaining over 92 % CV degradation efficiency after five cycles. The Ag2MoO4/MIL-101(Fe)/Ag composite demonstrates great potential for efficient and stable organic dye degradation, promising advancements in water treatment applications.

Robust design strategy using a scaffold based Turing machine model--- Application to PDI based dyes

This study turns the design and screen of new compounds into a computer integer crunch of the control arrays using a scaffold based Turing machine model. If small organic fragments are stored in a fragment database (FDB) in which each fragment is labelled by an integer in an array, the position and frequency of the integer control how the fragment clicks on a scaffold (template compound). This method can robustly screen a large number of candidate fragments for solar cells and other applications such as drug design with minimal human assistance. As a proof of concept, we consider terminal imide substituents on the core perylene diimide (PDI) to develop PDI derivatives capable of absorbing UV–vis light for solar cell applications. Time dependent-density functional theory (TD-DFT) method was employed in the calculations. When the imide substituents are electron donors such as azobenzene (DPI-7), they produce a larger bathochromic shift (Δλmax) from the core DPI band position. The UV–vis absorption transitions of these DPI derivatives have more charge transfer (CT) character, as the highest occupied molecular orbitals (HOMO) are located on the fragments rather than the core DPI region. Our study presents a robust and efficient high-performance organic dye screen design strategy, and further research in DPI-based solar cell design will focus on promoting the HOMO to LUMO transitions of the optical spectra.

Investigation on swelling behavior of sodium alginate/black titania nanocomposite hydrogels and effect of synthesis conditions on water uptake

Polymeric nanocomposite hydrogels were developed from a hydrophilic natural polymer, sodium alginate (SA) with black nano crystalline titania (black TiO2) by using ionic cross linker CaCl2, in view of the possible enhancement in properties of SA towards water treatment application. The optimum conditions for the preparation of films were done by varying the amount of cross-linking agent, cross-linking time and the amount of black nano crystalline TiO2. The nanocomposite hydrogels were then characterized by X-ray diffraction studies (XRD), fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The surface morphologies of the nanocomposite have been examined by using scanning electron microscopy (SEM). The swelling studies and its kinetics have been investigated under diverse PH conditions. Permeability of the gels were assessed in terms of film characteristics and PH. The results proved that the gels exhibit PH sensitivity. Based on the results, we have proposed a possible mechanism of water transport through the gels. The developed SA/black TiO2 nanocomposite hydrogels have been successfully employed for the efficient degradation organic dyes such as methylene blue and malachite green. The experimental results of dye degradation studies have been compared with theoretical models and it has been observed that the dye degradation follows pseudo second order kinetics for both methylene blue and malachite green. By altering the PH, the nanocomposite hydrogels can be broken and spent TiO2 can be recovered.

Synthesis of phenyl-based hyper-crosslinked porous organic polymers via Friedel-Crafts reaction for efficient organic dye adsorption

Hyper-crosslinked polymers (HCPs) with high specific surface areas and porous structural characteristics serving as adsorbents are currently a hot research topic. In this paper, a series of one-step 3D structured phenyl-based hyper-crosslinked porous polymers via Friedel-Crafts reaction namely POP-TB with different feeding ratios were successfully synthesized. POP-TB exhibits excellent adsorption performance towards four organic dyes including Rhodamine B, Acid green, Reactive blue, Crystal violet and the maximum adsorption capacity (qm) are 1065, 2542, 1900 and 1270 mg g−1, respectively, surpassing most of the adsorbents in previous reports.

Synergistic organic dye degradation and hydrogen production using Bi2Te3/Te/C single-catalyst nanowires

Over-consumption of limited fossil fuels has caused serious environmental pollution and a global energy crisis, threatening human life and biodiversity. As an ideal, environmentally friendly renewable energy, hydrogen can satisfy human clean energy requirements. Therefore, whether hydrogen can be catalytically generated in the wastewater treatment process is a highly meaningful investigation. Herein, Bi2Te3/Te/C heterojunction nanowires with high specific surface area and rich pore structure were successfully synthesized. The efficient catalytic degradation process is accompanied by the generation of hydrogen. The catalytic degradation of methylene blue and methyl orange was achieved in less than 20 s and 150 s, respectively. Meanwhile, in scaled-up degradation/hydrogen production experiments, fast and efficient H2 production from NaBH4 can be realized in the presence of Bi2Te3/Te/C nanowires. The mechanism of efficient synergistic organic dye degradation and hydrogen production is due to the efficient carrier transfers and accumulation at the hetero-interface. In contrast to previous work, rapid degradation of organic dyes and hydrogen production by decomposition of NaBH4 were achieved without the help of high-cost catalysts such as precious metals. This work could provide an alternative pathway for the future degradation of organic matter in synergistic heterogeneous catalytic wastewater and recovery of by-products including hydrogen.