Non-toxic Solvent Research Articles

The Extraction of Alcea Rosea Organic Dye and Its Characterization of Optical Properties

In the present study, the optical properties of a natural dye extracted from Alcea rosea flowers were investigated. The color extraction procedure was performed using a nontoxic solvent ethanol to enhance human safety and the ecological framework. Fourier transform infrared spectroscopy was employed to determine the functional groups of the natural dye obtained from Alcea rosea flowers. The optical properties of dye were achieved by the directed thin film using UV-Vis spectroscopy and analyzed absorption spectra, coefficients, refractive indices, extinction coefficients, and optical energy bandgap. A broad absorption band occurs over an extensive waveband with peak at 380 nm. The occurrence of a low indirect bandgap in a thin film was discerned at 3.9 eV, with Urbach energy noticed in a state of 0.23 eV.

Photoreductive N-N Homocoupling Catalyzed by a Superphotoreductant.

Azines are valuable synthons or target molecules in organic synthesis. In this work, we report that CBZ6 could work as a photoreductive catalyst for the N-N homocoupling of oximes in high efficiency. This therefore enabled convenient access to a large variety of azines from the corresponding aryl and alkyl ketones, as well as aryl aldehydes in up to 99% yield. 2,4-Dinitrophenoxyl was used as the recyclable auxiliary and the CBZ6 photocatalyst could also be recycled. These together with the low catalyst loading (2 mol % of CBZ6), the short reaction time (4 h), and the nontoxic DMSO solvent make the current process a sustainable and practical alternative to the classic methods.

Synthesis of Sm‐TADDbBP@MCM‐41 as a Robust, Reusable, and Practical Nanocatalyst in the Homoselective [2 + 3] Cycloaddition Reaction

ABSTRACTSchiff‐base materials are known ligands for the coordination of metal ions and the synthesis of various stable and useful complexes. Therefore, herein, a novel Schiff‐base compound {2,2′‐((1E,11E)‐2,5,8,11‐tetra azadodeca‐1,11‐diene‐1,12‐diyl) bis (4‐bromophenol)} was introduced that formed from condensation of triethylenetetramine (TETA) and 5‐bromo‐2‐hydroxybenzaldehyde (5B2HB). This Schiff‐base ligand was labeled as TADDbBP. Besides, mesoporous MCM‐41 was synthesized using tetraethyl orthosilicate (TEOS), hydrolyzing cetyltrimethylammonium bromide (CTAB) and NaOH solution (2 M), followed by calcination at 550 °C, and further, the silanol sites on the MCM‐41's surface were modified by 3‐chloropropyltriethoxysilane (3Cl‐PTES), which modified MCM‐41 was labeled as 3‐Cl‐Pr@MCM‐41. In the next step, the synthesized TADDbBP (as Schiff‐base ligand) was grafted on 3‐Cl‐Pr@MCM‐41, which was labeled as TADDbBP@MCM‐41, and further, it was coordinated with samarium ions (which was labeled as Sm‐TADDbBP@MCM‐41 nanocatalyst) using Sm (CH3COO)3. This is the first report on the production of Sm‐TADDbBP@MCM‐41 nanocatalyst, this nanocatalyst was characterized by TEM, SEM, EDX, elemental mapping, BET method, ICP, XRD, and TGA techniques. In the final step, the catalytic performance of Sm‐TADDbBP@MCM‐41 nanocatalyst has been checked in the homo‐selective producing of tetrazoles through [2 + 3] cycloaddition of benzonitriles and sodium azide (NaN3) in PEG‐400 as available, nontoxic, green, and safe solvent. This nanocatalyst provides excellent selectivity in the synthesis of tetrazoles. In addition, Sm‐TADDbBP@MCM‐41 nanocatalyst can be separated and recycled for several cycles without significant reactivation or metal leaching.

Direct Synthesis of Saturated Alcohols from Conjugated Ketones Using NaBH4 and Catalytic Amount of CuCN in Ethanol: Additive Catalysis with a Lithium Salt or a Sodium Salt.

A direct, efficient, and highly chemoselective synthesis of saturated alcohols through one-pot sequential 1,4- and 1,2-reduction of cyclic and acyclic conjugated ketones is reported. The saturated alcohols are obtained in very good yields using sodium borohydride (NaBH4) as a reducing agent and a catalytic amount of copper(I) cyanide (CuCN) in ethanol as a green solvent. This nontoxic solvent significantly favors full 1,4-reduction, as opposed to methanol. Selectivity is further enhanced by the combination of two additives (a lithium salt or a sodium salt, such as NaI).

Mechanochemical synthesis and characterization of poly[(aniline-co-N-(4-sulfophenyl) aniline] nanofibers and its nanocomposite with titanium dioxide nanoparticles and study of their efficiency in hybrid solar cell

The advantages of polyaniline for application in new generation solar cells include its cost-effectiveness, environmentally friendly synthesis, remarkable stability, and the ability to modify the bandgap through the synthesis of its nanocomposites. But a challenge for its nanostructures is the limited solubility in non-toxic solvents, including water, which limits their processability in coating techniques. We overcame this challenge by synthesizing its copolymer with diphenylamine-4-sulfonate and its nanocomposite with titanium dioxide nanoparticles (TiO2NPs). So through a solid-state and template-free technique and using sodium diphenylamine-4-sulfonate, aniline hydrochloride salt, TiO2NPs, and FeCl3∙6 H2O as an oxidant, poly(N-(sulfophenyl)aniline) nanoflowers (PSANFLs), poly [(aniline-co-N-(4-sulfophenyl) aniline] nanofibers (PAPSANFs), poly(N-(sulfophenyl)aniline) nanofibers/titanium dioxide nanoparticles (PSANFs/TiO2NPs), and poly (aniline-co-N-(4-sulfophenyl)aniline nanofibers/titanium dioxide nanoparticles (PAPSANFs/TiO2NPs) were synthesized. Characterization of the synthesized samples was carried out through field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectra, ultraviolet-visible spectra (UV-Vis), cyclic voltammetry (CV), and elemental analysis (CHNS). The FE-SEM images clearly illustrate that the synthesized samples are of nanoscale dimensions. The band gap values of 2.23 eV for PSANFs/TiO2NPs and 1.96 eV for PAPSANFs/TiO2NPs nanocomposites were determined through electrochemical calculations based on cyclic voltammetry curves, showcasing the complementary properties of n and p semiconductors. Using doctor blade method to prepare films from synthesized materials and the architectural pattern of ITO│TiO2NPs│semiconductor sample│Al, all hybrid solar cells are fabricated. The I-V characteristics and power conversion efficiency (PCE) of the samples were examined and discussed. The PCE values for the four samples were found to be in the range of 0.20–0.82 %.

Acidic dimethyl sulfoxide: A solvent system for the fast dissolution of pectin derivatives suitable for subsequent modification

This study investigates the use of dimethyl sulfoxide (DMSO) as a solvent for the dissolution and subsequent chemical modification of various pectin derivatives. DMSO was found to effectively dissolve low-methoxy pectin, high-methoxy pectin, polygalacturonic acid hydrazide, pectin amide, and polygalacturonic hydroxamic acid when the negative charges on the polysaccharide backbone were neutralized with organic acids. The dissolution process was further enhanced by increasing the temperature, although higher temperatures also promoted chain cleavage. The dissolved pectin derivatives were successfully modified through transesterification and Schiff base formation, demonstrating the potential of acidic DMSO as a non-toxic and cost-effective solvent system for homogeneous pectin chemistry. The study opens new possibilities for the functionalization of pectin in various industrial and biomedical applications.

Three-component Synthesis of Tetrahydrobenzo[b]pyrans Using MMWCNTs-PEG-IL as a Novel Magnetic Immobilized Ionic Liquid

Introduction: A novel immobilized imidazolium type ionic liquid was synthesized using poly(ethylene glycol) (PEG) functionalized magnetic multi-walled carbon nanotubes. This immobilized ionic liquid (MMWCNTs-PEG-IL) was characterized by FT-IR, VSM, XRD, FE-SEM and EDX analysis. Method: Then, it was used as a magnetic catalyst in a three-component reaction to yield tetrahydrobenzo[b]pyran derivatives. First, optimized reaction conditions were investigated. A mixture of containing dimedone (1 mmol), malononitrile (1 mmol), benzaldehyde (1.2 mmol) and MMWCNTs-PEG-IL (0.03 g) in H2O/EtOH (5 mL) was stirred at 70 °C. After completion of the reaction, the mixture was cooled. Results: Then, an external magnet was used to separate the magnetic catalyst. This method has many advantages including high reaction yields, high TOFs, using non-toxic solvents, easy handling of catalyst, simple separation of catalyst from reaction medium and short reaction times. Conclusion: Also, the reusability of the magnetic catalyst has been investigated in 7 runs without serious loss of reaction yield.

Stable and sustainable perovskite solar modules by optimizing blade coating nickel oxide deposition over 15 × 15 cm2 area

Perovskite solar cells have rapidly advanced, achieving over 26% power conversion efficiency on the laboratory scale. However, transitioning to large-scale production remains a challenge due to limitations in conventional fabrication methods like spin coating. Here, we introduce an optimized blade coating process for the scalable fabrication of large-area (15 cm × 15 cm) perovskite solar modules with a nickel oxide hole transport layer, performed in ambient air and utilizing a non-toxic solvent system. Self-assembled monolayers between the nickel oxide and perovskite layer improve the uniformity and morphology of the perovskite film. Perovskite solar modules with a 110 cm2 active area achieve a power conversion efficiency of 12.6%. Moreover, encapsulated modules retained 84% of their initial efficiency after 1,000 hours at 85 °C in air (ISOS-T-1). This study demonstrates progress in the large-scale production of perovskite solar cells that combine efficiency with long-term stability.

Water Extract of Onion Catalyst: A Sustainable Approach for the Synthesis of 4-Substituted 1,5-Benzodiazepine Derivatives via an In Situ Generated Enaminones

Background: A simple, convenient and environmentally benign green protocol has been developed for the one-pot synthesis of 4-substituted-1,5-benzodiazepines through three-component reaction of 1,2-diamine, 1,3-cyclic diketone with an aldehyde catalyzed by water extract of onion. The reaction conditions were optimized and the scope of the reaction was extended to various 1,2- diamines, 1,3-cyclic diketones and aldehydes. The main advantages of this method are good to excellent yields, easy workup, simple experimental procedure, and an ability to tolerate a variety of functional groups which gives cost-effective as well as green rewards. The structure of compound 5f was confirmed by single crystal X-ray analysis. Objective: A methodology developed for the synthesizing of 4-substituted 1,5-Benzodiazepine derivatives via enaminones intermediates using 1,2-diamine, 1,3-cyclic diketone and aldehyde in environmentally friendly ethanol as medium. Methods: As a more environmentally friendly catalyst for producing products containing benzodiazepines using aqueous extract of onion. The devised method was proven reliable, non-toxic and greener solvent with quick work-up to produce the intended product. Results: Here, using a one-pot, three-component reaction with a dimedone, 1,2-diamine and range of aldehyde while using water extract of onion as a catalyst. The acquired experimental results showed that the employed synthesis methodology is a straightforward procedure that offers various benefits, including sustainability, easy separtion from the reaction medium. Conclusion: We have developed a sustainble approach for synthesizing benzodiazepine from radily available precursors under mild reaction conditions.

Formulation Design and Characterization of Nilotinib Polymeric Nanoparticles by Nanoprecipitation Technique for the Improved Drug Solubility and Dissolution Rate

Introduction: Nilotinib is a BCS class-IV poorly water-soluble kinase inhibitor drug, that was used for this study to prepare the polymeric nanoparticles by nanoprecipitation technique using Eudragit RL-100 and RS-100 as polymers, Killophore P-188 as a surfactant, and PEG 400 used as a non-volatile, and nontoxic solvent for the improvement of the drug solubility and dissolution rate. Method: The initial process and formulation variables are screened out based on the selected critical quality attributes such as drug release (%), particle size (nm), zeta potential (mV), and polydispersity index. The FT-IR and DSC studies reveal that the drug has no compatibility between the selected drug and the polymers and does not show any additional drug peaks after physical mixing and formulations. The prepared nanoparticles were further characterized to evaluate the particle size (nm), polydispersity index (PDI), zeta potential (mV), entrapment efficiency (%), and in-vitro drug release (%). From the in vitro drug release study, Eudragit RL-100 and Killophore P-188-based formulations showed optimum drug entrapment efficiency with improved drug solubility and dissolution rate in PEG 400 compared to Eudragit RS-100-based formulations. The accelerated stability data for the optimized formulation batch (F6) before and after storage conditions at 40±2 0C and 75±5% RH indicates that the optimized formulation (F6) is more stable for up to 6 months without changes in drug entrapment efficiency and in vitro dissolution rate. Dissolution kinetic data and diffusion exponent values suggested that optimized formulation followed the Higuchi model with a non-Fickian transport mechanism. Result: According to the results, the preparation method proposed in this study is the most suitable for generating polymeric nanoparticles of nilotinib for improved drug solubility and dissolution rate. Conclusion: The nilotinib-based polymeric nano-formulation proved a potential alternative for better drug release with an enhanced solubility rate.

Green Extraction of Plant Materials Using Supercritical CO2: Insights into Methods, Analysis, and Bioactivity.

In recent years, the supercritical CO2 extraction method has gained attention due to its use of environmentally friendly, non-toxic solvents, ability to operate at lower temperatures that do not cause the degradation of bioactive compounds, and capacity for rapid extraction. This method is particularly notable for isolating bioactive compounds from plants. The extracts obtained have shown superior properties due to their activity against diseases such as cancer, which is one of the leading causes of death worldwide. The aim of this study is to provide an in-depth understanding of the supercritical CO2 extraction method, as well as to discuss its advantages and disadvantages. Furthermore, the study includes specific data on various plant materials, detailing the following parameters: plant name and region, bioactive compounds or compound classes, extraction temperature (°C), pressure (bar), time (minutes), co-solvent used, and flow rate. Additionally, this study covers extensive research on the isolation of bioactive compounds and the efficacy of the obtained extracts against cancer.

(Invited) Sustainable and Non-Toxic Hydrogel-Based Dye-Sensitized Solar Cell: Performance Evaluation Under Indoor Illumination

Indoor photovoltaics have gathered growing interest amongst researchers, as a mean to exploit the indoor lighting we use in our daily life to power small devices. Dye-sensitized solar cells (DSSCs) represent good candidates for such applications[1]. However, when it comes to indoor applications, there is an increased demand for non-toxic and non-flammable solvents for electrolytes. The implementation of water-based electrolytes is a promising way to address these issues, whilst also ensuring the eco-friendliness and sustainability of these devices[2]. In this work, aqueous gel electrolytes incorporating a iodide/triiodide redox couple were made with a bio-sourced polymer, xanthan gum[3]. DSSCs were assembled using screen-printed TiO2 semiconducting layers treated with TiCl4 and sensitized with an organic dye, D131. As counter electrode, Pt sputtered FTO was used. The performance of the cells was investigated under indoor light intensities between 500 and 1000 lux.[1]: Jilakian, M., & Ghaddar, T. H. (2022). Eco-Friendly Aqueous Dye-Sensitized Solar Cell with a Copper (I/II) Electrolyte System: Efficient Performance under Ambient Light Conditions. ACS Applied Energy Materials, 5(1), 257-265.[2]: Bella, F., Gerbaldi, C., Barolo, C., & Grätzel, M. (2015). Aqueous dye-sensitized solar cells. Chemical Society Reviews, 44(11), 3431-3473.[3]: Galliano, S., Bella, F., Bonomo, M., Viscardi, G., Gerbaldi, C., Boschloo, G., & Barolo, C. (2020). Hydrogel electrolytes based on xanthan gum: green route towards stable dye-sensitized solar cells. Nanomaterials, 10(8), 1585.

Greener alternative screen printable ink formulation for the development of flexible reference electrodes

Greener alternatives for high demand materials is becoming increasingly necessary. Conductive screen printable ink formulations are vital components of sensors, e.g., for glucose monitoring in diabetics, and printable electronics. Here, the formulation of a reliable, low-cost, high-performance and greener alternative of an Ag/AgCl screen-printable ink formulation is reported. The ink formulation has a significantly lower silver nanoparticle loading, 25 %, is based on a nontoxic organic solvent and uses a biodegradable polymeric mixture of polyhydroxyether/polyether resin (ratio of 1:2). The cytotoxicity of the Carbon/Ag/AgCl Ref SPE was evaluated and compared to screen-printed electrodes based on a commercial ink formulation. The Carbon/Ag/AgCl Reference screen printed electrodes (Carbon/Ag/AgCl Ref SPE) demonstrated good reproducibility, high analytical performance (RSD% 2.45) and the reference potential is highly stable in the electrochemical detection of glucose using a commercial glucose meter.

Comparison of different green extraction methods used for the extraction of anthocyanin from red onion skin.

Green extraction primarily emphasizes developing new extraction techniques that consume less energy. It involves using safe, non-toxic alternative solvents and sustainable natural resources to ensure the production of safe and high-quality extracts. Red onion skin is an important source of anthocyanins, a subgroup of phenolic compounds. Anthocyanins are an important group of natural pigments that have attracted a lot of attention due to their health benefits. However, the instability and high sensitivity of these pigments have limited their use in food and cosmetics. Therefore, in this study, various modern green extraction methods were used, including solvent extraction, ultrasound-assisted extraction, subcritical water extraction, microwave-assisted extraction (MAE), pulsed electric field extraction, supercritical fluid extraction (SFE), and high hydrostatic pressure-assisted (HHPAE) extraction, to specifically extract and purify anthocyanins. The extraction efficiency, specifically targeting anthocyanins, showed the highest efficiency with HHPAE (81.84%) and the lowest with MAE (40.01%). Measurement of total anthocyanin content revealed that HHPAE and SFE methods yielded the highest anthocyanin concentrations, with 248.49 and 244.98 mg/L, respectively. Identification of anthocyanin by LC-MS revealed that the main anthocyanidins in red onion peel are pelargonidin, cyanidin, delphinidin, and petunidin. These results indicate that innovative green extraction methods, particularly HHPAE and SFE, can effectively replace conventional techniques due to their superior efficiency and enhanced preservation of anthocyanin compounds.

MIL-101(Cr) supported Pt and Au-Pt composites as active catalysts for the selective hydrogenation of nitrobenzene under mild reaction conditions

In this study, we report the successful synthesis of monometallic Pt(2 wt.%)/MIL-101(Cr) and bimetallic Au(1 wt.%)-Pt(1 wt.%)/MIL-101(Cr) catalysts with low dimension MeNPs by the double-solvent (DS) method. The catalysts were characterized by powder X-ray diffraction (PXRD), N2 sorption analysis (BET), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), and transmission electron microscopy (TEM). The characterization results demonstrated the presence of well-dispersed Pt and Au-Pt nanoparticles (2.9 and 2.7 nm, respectively), located mainly inside the pores of MIL-101(Cr). The stronger interaction of Au-Pt NPs with the support compared to Pt NPs was demonstrated by H2-TPR and XPS, which proved the existence of charge exchange between Pt NPs and Cr from MIL-101 in the case of Au(1 wt%)-Pt(1 wt%)/MIL-101(Cr), but not in the case of Pt(2 wt%)/MIL-101(Cr). The composite materials were tested in the catalytic selective hydrogenation of nitrobenzene to aniline in liquid phase under mild conditions (low temperature, low hydrogen pressure), and in the presence of a biomass-derived non-toxic solvent (ethanol). The bimetallic Au(1 wt%)-Pt(1 wt%)/MIL-101(Cr) catalyst showed superior catalytic activity as compared to the monometallic Pt(2 wt%)/MIL-101(Cr) catalyst. This is due to the synergetic effect between the two metals as demonstrated by the projected density of states studies.

Effect of PVDF, HA, and AgNO3 Annealing on β-Phase, Optical, and Mechanical Properties

Typically, polymer composites and ceramics are used to create biosensors. Materials with properties that are ideal for biosensors and chemical sensors include AgNO3 (silver nitrate), PVDF (polyvinylidene fluoride), and HA (hydroxyapatite). Polyvinylidene fluoride (PVDF) polymer has been widely used in several applications because of its well-known superior ferroelectric characteristics and biocompatibility. The brittleness and low bending strength of hydroxyapatite limit its applicability. Several HA and polymer composite formulations have been developed to compensate for HA’s mechanical weakness. The final product contains a significant amount of HA, making HA/polymer composites highly biocompatible. When the right amount of silver is deposited, the maximum piezoelectric activity is generated, and silver nitrate has antimicrobial properties. The non-toxic solvent DMSO (dimethyl sulfoxide) and the solvent casting method were chosen for the preparation of the film. Surface roughness was chosen to measure the Str and Sdr properties of the thin film. For liquid preparation, the multifractal spectra analysis was chosen for each sample. SEM was used to examine the samples morphologically. EDX and mapping analyses were presented for chemistry distribution in the samples.

High-energy density ultra-thick drying-free Ni-rich cathode electrodes for application in Lithium-ion batteries

Lithium-ion batteries (LIBs) can be considered as one of the pivotal components required to succeed in the drive towards a greener future. However, the current processing methods for the cathode electrode make it harmful and costly due to the toxic solvent drying and recovery stages. Additionally, the reliance on LIBs particularly emphasizes the imperative for increased energy density in both volume and weight, which predominantly relies on the cathode. To surmount these challenges, this research analyses the true requirements of a novel process and introduces a novel solvent-assisted binder (SaB) dry electrode approach to satisfy them. This innovative method incorporates a low-boiling point and relatively non-toxic solvent (ethanol) at less than 3 wt.%, enhancing the processability of the electrode without compromising safety, cost reductions, or environmental impact associated with traditional dry processes. The SaB process allows the calendaring to cause less damage to the electrode thanks to the binder distribution and allows for better fibrillization of the binder, improving the electrode microstructure. Over 100 cycles at 1C, the SaB dry electrode achieves 77.70% capacity retention, surpassing the standard dry electrode's 72.39% at a loading of approximately 30 mg cm−2 and is also capable of performing at ultra-high loadings up to 60 mg cm−2.

A novel method of flash‐hydrolysis assisted pigment extraction (carotenoids) from microalgae biomass

AbstractThe human body can easily convert β‐carotene into retinol (a precursor of vitamin A), a significant ingredient in dietary supplements. The need for commercial natural pigment production, including β‐carotene, has led to intensive research in this area. Processing after biosynthesis is a vital stage that involves the use of nontoxic solvents, efficient mechanical disruption of cells, and the isolation of the required compounds. With the growing popularity of green extraction methods and the increasing market demand for carotenoids due to their health benefits, the use of clean, nontoxic, flash‐hydrolyzed biomass for carotenoid production presents a significant advantage. Furthermore, the remaining biomass can serve as a protein source for animal feed, thereby aligning with the principles of the biorefinery concept. In this study, our aim was to optimize the disruption of cells in two microalgal species using flash hydrolysis (FH). We applied two distinct levels of pressure and four separate temperature conditions over a brief residence time. Following this, we employed an ethanol extraction method to assess the efficiency of carotenoid pigment extraction. Flash hydrolysis is a chemical‐free subcritical water‐based continuous‐flow process, injected with wet biomass slurry at a high temperature (150–250 °C) for a very short time (8–12 s) to obtain bioproducts. In this study, we discovered that the pigment β‐carotene constituted 0.04 to 0.3% of the dry biomass in the case of Chlorella vulgaris. Bands of lutein and zeaxanthin were also observed in the thin layer chromatography (TLC) analysis of the treated slurry. This was achieved under conditions of an effective temperature of 200 °C and a pressure of 1700 psi. The Arthrospira platensis (1Tex), β‐carotene yield was 0.014 to 0.021% of dry biomass. Some lutein and zeaxanthin bands were also found in the treated slurry with an effective temperature of 150 °C and 1000 psi pressure. This study reports pigment extraction by FH for the first time. It is a viable process to scale up high‐value natural products like carotenoids from microalgae at the industrial level without adverse environmental impacts. Due to low residence time, the temperature does not have a negative effect on pigments; cell rupture was accomplished effectively using water as a solvent. A considerable amount of pigment could be recovered from microalgae at specific combinations of temperature and pressure depending on the type of cell wall that microalgae possess.

Sustainable membrane technology for water purification—Manufacturing, recycling and environmental impacts

Water pollution has become a serious threat to our ecosystem. Water contamination due to human, commercial, and industrial activities has negatively affected the whole world. Owing to the global demanding challenges of water pollution treatments and achieving sustainability, membrane technology has gained increasing research attention. Although numerous membrane materials have focused, the sustainable water purification membranes are most effective for environmental needs. In this regard sustainable, green, and recyclable polymeric and nanocomposite membranes have been developed. Materials fulfilling sustainable environmental demands usually include wide-ranging polyesters, polyamides, polysulfones, and recyclable/biodegradable petroleum polymers plus non-toxic solvents. Consequently, water purification membranes for nanofiltration, microfiltration, reverse osmosis, ultrafiltration, and related filtration processes have been designed. Sustainable polymer membranes for water purification have been manufactured using facile techniques. The resulting membranes have been tested for desalination, dye removal, ion separation, and antibacterial processes for wastewater. Environmental sustainability studies have also pointed towards desired life cycle assessment results for these water purification membranes. Recycling of water treatment membranes have been performed by three major processes mechanical recycling, chemical recycling, or thermal recycling. Moreover, use of sustainable membranes has caused positive environmental impacts for safe waste water treatment. Importantly, worth of sustainable water purification membranes has been analyzed for the environmentally friendly water purification applications. There is vast scope of developing and investigating water purification membranes using countless sustainable polymers, materials, and nanomaterials. Hence, value of sustainable membranes has been analyzed to meet the global demands and challenges to attain future clean water and ecosystem.

Synthesis of 3, 3′- bis (indolyl) methanes using Bio-Waste metal free super acid as efficient with recyclable catalysts

A bio-waste metal free sulfonated carbonaceous super acid catalyst (BWC) is generated from sodium lignosulphonate, which is obtained from bio-waste sulphite pulping process of paper making industries. Here, we report a highly efficient catalytic a sulphonated carbon material catalyzed electrophilic substitution reactions of indoles with aromatic aldehydes to afford 3,3′-bisindolylmethane (BIM) derivatives. The synthesized BIM compounds were characterized by modern analytical techniques like NMR, MS, FT-IR, CHNS analysis. The BWC green catalyst was characterized by FT-IR, thermal gravimetric analysis (TGA) scanning electron microscopy (SEM), thermal electronic microscopy (TEM) with elemental analysis. The significant features of this catalysis are easy catalyst preparation, high product yields, environmental benignity, short reaction time, broad substrate scope, with use of non-toxic solvents. The catalysts could be recycled with reused three times without decrease in the catalytic activity significantly.