Chloroacetic Acid Research Articles

Ultrafast complete dechlorination enabled by ferrous oxide/graphene oxide catalytic membranes via nanoconfinement advanced reduction

Chlorinated organic pollutants widely exist in aquatic environments and threaten human health. Catalytic approaches are proposed for their elimination, but sluggish degradation, incomplete dechlorination, and catalyst recovery remain extremely challenging. Here we show efficient dechlorination using ferrous oxide/graphene oxide catalytic membranes with strong nanoconfinement effects. Catalytic membranes are constructed by graphene oxide nanosheets with integrated ultrafine and monodisperse sub-5 nm nanoparticles through simple in-situ growth and filtration assembly. Density function theory simulation reveals that nanoconfinement effects remarkably reduce energy barriers of rate-limiting steps for iron (III)-sulfite complex dissociation to sulfite radicals and dichloroacetic acid degradation to monochloroacetic acid. Combining with nanoconfinement effects of enhancing reactants accessibility to catalysts and increasing catalyst-to-reactant ratios, the membrane achieves ultrafast and complete dechlorination of 180 µg L−1 dichloroacetic acid to chloride, with nearly 100% reduction efficiency within a record-breaking 3.9 ms, accompanied by six to seven orders of magnitude greater first-order rate constant of 51,000 min−1 than current catalysis. Meanwhile, the membranes exhibit quadrupled permeance of 48.6 L m−2 h−1 bar−1 as GO ones, because nanoparticles adjust membrane structure, chemical composition, and interlayer space. Moreover, the membranes show excellent stability over 20 cycles and universality for chlorinated organic pollutants at environmental concentrations.

Improved Hydrothermal Conversion of Pea Pod Biomass for Production of Platform Chemicals with Organic Acid Catalysts

Agro-industries produce over 2 billion tons of agricultural waste annually, including by-products like bagasse, molasses, seeds, stems, leaves, straw, and shells. The use of agro-industrial waste is a way to reduce the impact of industrial processes on the environment. The pea pod is a biomass with a high concentration of cellulose, hemicellulose and some lignin; therefore, it can be used to produce platform chemicals by means of a hydrothermal process. There is limited research on the hydrolysis of pea biomass, but it has been shown to obtain high yields. This study analyzed the effectiveness and selectivity of the hydrothermal process using pea pod biomass with a particle size of 0.5 mm at 180 °C for one hour. A 500 mL reactor was used, with a biomass-to-acid solution ratio of 1:20. The concentration of the acid solution was 0.02 M. The concentrations of sugar, formic acid, levulinic acid, HMF, and furfural produced were measured. Among the catalysts studied, adipic acid catalysis showed the highest yield of 65.16%, with 37.09% of sugar, 16.37% of formic acid, and 11.71% of levulinic acid. On the other hand, the catalysts with chloroacetic acid, butyric acid, anthranilic acid, and phthalic acid were less effective but demonstrated selectivity for sugar production, proving that the liquid phase obtained using the catalyst with those acids can be used as carbon sources for a fermentation process. In general, when comparing the process with or without the use of a catalyst, it is observed that with a catalyst in the reaction, the amount of HMF and furfural produced is reduced and the selectivity with respect to sugar production is increased.

The efficacy of cryotherapy compared to the other modalities for the management of palmoplantar warts: a systematic review and network meta-analysis

There are several treatment modalities for Palmoplantar Warts (PPW) introduced, but none have been proven to be significantly effective in all patients. The study aims to assess the efficacy and safety of cryotherapy compared to other modalities for PPW. Searches were conducted in Medline, Embase, Scopus, and CENTRAL databases, along with additional reference and citation tracking from included studies. Randomized Controlled Trials (RCTs) comparing various treatments for PPW were included. Two independent pairs extracted the data from the included studies. Outcomes assessed included cure rates, pain scores, recurrence rates, and adverse events. Network meta-analysis using Netmeta in R software was utilized, with treatments ranked by p-scores. A total of 27 RCTs that enrolled 2,539 participants were deemed eligible. As per p-scores, needling yielded the highest odd for the cure rate (p=1.00), followed by intralesional injection of the Measles, Mumps, and Rubella (MMR) vaccine (p=0.90). For the pain score, 76% topical monochloroacetic acid (p=0.13) showed the lowest mean pain score, while cryotherapy yielded the highest score (p=0.90). Furthermore, cryotherapy showed the highest odds for recurrence rate (p=0.75), followed by intralesional injection of Candida antigen (p=0.61). 0.05% intralesional bleomycin (p=0.93) was the highest agent for adverse events rate, followed by cryotherapy (p=0.61). Needling was the most effective in achieving a cure rate. Cryotherapy has the highest odds for pain score and recurrence rate, while 0.05% intralesional bleomycin has the highest adverse events profile.

Frabrication of carboxymethylchitin nanofibers and fish gelatin hybrid gels with robust gel performance

Compared to animal gelatin, the application of fish gelatin (FG) in the food industry is limited due to its lower gel hardness, gelation temperature, and melting temperature. To address these issues, we developed hybrid gels using carboxymethyl chitin nanofibers (CMC-NFs) with FG to enhance its gel properties. The chitin was carboxymethylated by monochloroacetic acid, increasing the negative potential from −6 mV to −35 mV. This modified chitin was then defibrillated into CMC-NFs through high-pressure homogenization to improve its water dispersibility. The addition of 0.1% CMC-NFs significantly increased the hardness of FG gels from 533 g to 989 g, which was notably higher than the ∼600 g hardness of porcine gelatin. Additionally, the gelation and melting temperatures of FG reached 17 °C and 32 °C, respectively, which are very close to the 20 °C and 35 °C of porcine gelatin. Mechanistic studies revealed that FG and CMC-NFs (0.1%) molecules formed a synergistic gel network, facilitated by hydrogen bonding and hydrophobic interactions. This interaction significantly increased the α-helix content in the secondary structure of the FG protein from 15.26% to 21.18%, thereby enhancing the FG-dominated three-dimensional network structure with CMC-NF molecules. Increasing the concentration of CMC-NFs further elevated the gel's melting temperature while reducing its hardness due to phase separation. This study not only presents a viable method for enhancing the gelling properties of modified FG but also offers a feasible solution for expanding FG's applications in the food industry.

Aromatic Structures Govern the Formation of Chlorinated Byproducts in Dichlorine Radical Reactions.

Radical-induced disinfection byproduct (DBP) formation is drawing attention with increasing applications of advanced oxidation processes (AOPs). Cl2•- represents one of the extensively generated radicals in AOPs, whose behavior in DBP formation remains unknown. In this study, we found that aromatic structures serve as the main DBP precursors in Cl2•- reactions by employing diverse groups of model compounds. At a typical Cl2•- exposure of 1.2 × 10-9 M·s, the sum concentrations of 7 regulated aliphatic DBPs (e.g., trichloromethane, chloroacetic acids) are ∼0.10 to 0.48 μM for aromatic precursors and <0.05 μM for aliphatic ones. The DBP formation mechanisms from Cl2•- reactions involved the formation of chlorinated aromatics, radical-induced oxygen incorporation followed by ring cleavage, and the interactions of Cl2•- with ring-cleavage intermediates. In reacting with DOM, Cl2•- reactions produced much fewer aliphatic DBPs (5% of the total organochlorine vs 40% for chlorination) and chloroacetic acids dominated the aliphatic DBPs (usually trihalomethane for chlorination), which can be well interpreted by the precursors and mechanisms proposed. This work comprehensively reveals the precursors, formation patterns, and mechanisms of DBPs during the less-studied Cl2•- reactions, highlighting the importance of eliminating the aromatic structures of DOM before the AOPs.

Advanced reduction processes initiated by oxidative radicals for trichloroacetic acid degradation: Performance, radical generation, and mechanism

The degradation of haloacetic acids (HAAs) in aqueous environments poses a challenge due to their oxidative resistance. Given that HAAs are highly carcinogenic disinfection byproducts, it is imperative to develop effective degradation methods to reduce their potential health risk. In this study, we found that only 27.2% of 200 μM trichloroacetic acid (TCA) was removed in the UV-activated persulfate (PS) system after 2 h, while complete removal was achieved with the addition of 15 mM formic acid (FA). The main products of TCA degradation were dichloroacetic acid and monochloroacetic acid. Results from free radical quenching experiments and electron paramagnetic resonance spectroscopy analyses indicated that reductive carbon dioxide radical (CO2•−) was the main active species responsible for TCA reduction. Oxidative radicals (i.e., SO4•− and •OH) generated from PS activation reacted with FA to form CO2•−, efficiently degrading TCA. The effects of PS and FA concentrations, solution pH, anions (e.g., Cl−, SO42−, and HCO3−), and small organic molecules (e.g., methanol, ethanol, and acetic acid) on degradation efficiency were examined. Overall, this study proposes a simple and efficient method to improve the degradation efficiency of HAAs in the UV/PS system and provides new insights into the advanced reduction processes used for water treatments.

Mechanochemical oxidative complexation of copper(I) chloride with acetic acid, benzoic acid, their chloro derivatives and l-histidine affording anhydrous copper(II) complexes

This work reports solvent-free synthesis of copper(II)-carboxylates by grinding the reactants in solid state (the mechanochemical method). Here we used copper(I) salt to synthesize copper(II) complexes to demonstrate the potential of oxidative synthesis of the mechanochemical technique. The complexes were synthesized by grinding copper(I) chloride with a carboxylic acid together in 1:2 molar ratio in mortar and pestle. The carboxylic acids used were acetic acid, benzoic acid, 2-chloroacetic acid, 2-chlorobenzoic acid and l-histidine. The oxidative complexation occurred in the solid state producing anhydrous dimeric copper(II)-carboxylates (except that of l-histidine) in quantitative yield (>96%) having 1:2 metal to ligand ratio. The first evidence to oxidation of copper(I) to copper(II) ion was a change in color (pale to greenish blue) and a change in magnetic susceptibility from diamagnetic to paramagnetic value. The complexes were also characterized by elemental analysis, electronic absorption spectroscopy, FT-IR spectra, mass spectrometry, powder X-ray diffraction and thermal analysis. The electronic absorption, magnetic susceptibility, ESR and X-ray diffraction data supported a distorted square-planer geometry. This study provided for a distinct test in the form of magnetic susceptibility for the formation of copper(II)-complexes from a copper(I) salt. The dimeric nature of the complexes, except that of bis(histidinato)copper(II), was confirmed by the lower magnetic-moments (1.40–1.50 BM) than the spin only value (1.73 BM).

Antimicrobial activities of modified and unmodified pectin obtained from peels of Irvingia gabonensis, Cola milleni, and Theobroma cacao on specific pathogenic organisms

The antibacterial and antifungal activities of ethanolic extracts of pectin derived from the peels of Theobroma cacao, Cola milleni, and Irvingia gabonensis were investigated against phytopathogenic bacteria and fungi. The agar diffusion method was employed to test the extracts against Staphylococus aureus, Pseudomonas aeroginosa, Chromobacterium violaceum, Streptococcus feacalis, Xanthomonas axonopodis, Erwinia carotovora, Sclerotium rulfsii, Pythophthora palmivora, and Pyricularia oryzae. Significant differences (p&lt;0.05) were observed in all control groups. The extracts inoculated with Streptomycin exhibited the highest activity against all bacterial strains. Conversely, the unmodified extracts of pectin samples from cola, cocoa, and wild mango displayed the least inhibitory activity against the tested bacterial strains, while the modified extracts with Chloro Acetic Acid (CAA), Para Amino Benzoic Acid (PABA), and Para Nitro Benzoic Acid (PNBA) showed varying inhibitory effects. The control sample inoculated with Mancozeb demonstrated the highest zone of inhibition against all fungal strains in the three pectin samples. However, the modified pectin samples exhibited increased inhibitory effects compared to the unmodified pectin extract, although the results were closer to the control. The higher values of modified pectin can be attributed to the presence of modifying agents such as long-chain hydrocarbons, acetic acid, chloro compounds, carboxyl, benzene rings, amino groups, and nitro groups. The presence of secondary metabolites in the pectin samples may also contribute to the higher values observed in both modified and unmodified samples. Overall, the results indicate the fungicidal and bactericidal potential of the extracts against the tested organisms, suggesting their potential use as broad-spectrum antimicrobial agents.

Combined Toxic Effects and Mechanisms of Chloroacetic Acid and N-Nitrosodimethylamine on Submerged Macrophytes

Disinfection by-products (DBPs) such as chloroacetic acids (CAAs) and N-Nitrosodimethylamine (NDMA) are prevalent pollutants in surface waters, particularly with the increasing use of chlorine-based disinfectants. The entry of these DBPs into water bodies may increase accordingly, posing ecological risks to aquatic life. To assess the toxic effects of CAAs and NDMA on submerged macrophytes, Vallisneria natans was exposed to different concentrations of CAAs (1.0, 10.0, and 100.0 μg L−1) and NDMA (0.1, 1.0, and 10.0 μg L−1). A RI value of &lt;1 indicates that simultaneous exposure to CAAs and NDMA can produce an antagonistic effect. Both CAAs and NDMA adversely affect the photosynthetic system of plants. In the NDMA treatment group, chlorophyll a content decreases with increasing concentration, accounting for 96.03%, 60.80%, and 58.67% of the CT group, respectively. Additionally, it effectively triggers the plant’s antioxidant response, with significant increases in SOD, POD, and GSH levels. Among these, the combined treatment group AN2 (10 + 1 μg L−1) showed the most significant change in SOD activity, reaching 3.57 times that of the CT group. Ultrastructural changes also revealed stress responses in leaf cells and damage to organelles. Furthermore, metabolomics provided insights into the metabolic responses induced by CAAs or NDMA in V. natans leaves, where the composition and metabolism of lipids, fatty acids, cofactors and vitamins, amino acids, nucleotides, and some antioxidants were regulated, affecting plant growth. This study provides preliminary information for the ecological risk assessment of submerged plants by complex contamination with the disinfection by-products CAA and NDMA.

Hydrogen Storage Studies of Nanocomposites Derived From O‐Ethyl‐S‐((5‐Methoxy‐1H‐Benzo[d]Imidazol‐2‐Yl)Carbonothioate (OESMBIC) With ZnO and TiO2 Nanoparticles

ABSTRACT5‐Methoxy‐2‐mercaptobenzamidazole was used to synthesize O‐ethyl‐S‐(5‐methoxy‐1H‐benzo[d]imidazol‐2‐yl) carbonothioate (OESMBIC) by the reaction with chloroacetic acid ethyl ester in a KOH solution. The reaction product (OESMBIC) was characterized using Fourier transform infrared (FTIR), melting point, and 1H‐NMR. The characteristic results prove the formation of the target compound with high purity. Furthermore, the work includes the synthesis of ZnO and TiO2 nanoparticles via chemical methods in the high alkalinity solution. These nanoparticles were used to synthesize two novel nanocomposites named OESMBIC‐ZnO and OESMBIC‐TiO2. The synthesized nanocomposites were characterized by FTIR, SEM, EDX, TEM, and XRD. The results prove that the prepared titanium oxide as nanotubes with diameters ranging between 20 and 35 nm decorated with OESMBIC. The results prove that ZnO in OESMBIC‐ZnO was found as nanorods with different lengths and diameters of 40–65 nm decorated with OESMBIC molecules. The as‐prepared compounds; OESMBIC, OESMBIC‐ZnO, and OESMBIC‐TiO2 were used for the hydrogen storage application using the VTI method. The results prove that the addition of ZnO and TiO2 nanoparticles enhanced the storage ability of OESMBIC as the OESMBIC gave only 0.50 wt% at an equilibrium pressure of 40 bar, while it reached 2.40 and 4.37 wt% at equilibrium pressures of 60 and 75 bar for OESMBIC‐ZnO and OESMBIC‐TiO2, respectively.

Design, synthesis and activity screening of cedrol derivatives as small molecule JAK3 inhibitors

The JAK-STAT signalling pathway is considered to be a significant role involved in the regulation of inflammatory diseases and immune responses, which indicate that specific inhibition of JAK-STAT pathway would be a potential key strategy for RA (Rheumatoid arthritis) treatment. Cedrol (CE), found from ginger by our group earlier, has been proven to play an excellent role in ameliorating RA via acting on JAK3. In this study, 27 new (1, 3–28), along with one known (2) derivatives of CE were synthesized by using chloroacetic acid and acryloyl chloride as intermediate ligands. In vitro, the inhibition effect on JAK kinases were performed using HTRF (Homogenous Time-Resolved Fluorescence) detection technology, which is more convenient and stable than traditional methods. The results compared with the secretion of LPS-induced p-JAK3 can better reflect the true kinase-selective effect of the compounds. Compound 22 was identified as a potent inhibitor to reduce the secretion of LPS-induced p-JAK3 with a dose-dependent manner. Given these results, compound 22 could serve as a favourable inhibitor of JAK3 for further research.

Functionalization strategy of carboxymethyl cotton gauze fabrics with zeolitic imidazolate framework-67 (ZIF-67) as a recyclable material for biomedical applications

The accumulation of uremic toxins in the human body poses a deadly risk because it causes chronic kidney disease. To increase the effectiveness of hemodialysis and raise the survival rate, these toxins must be effectively removed from the bloodstream. Developing effective materials for removing these dangerous substances requires a thorough understanding of the interactions between an adsorbent and the uremic toxins. Thankfully, metal-organic frameworks (MOFs) have shown considerable promise for the identification and treatment of kidney disorders. Herein, cotton gauze fabrics (CGF) were carboxylated using monochloroacetic acid to produce carboxymethylated cotton gauze fabrics (CM-CGF). CM-CGF was subsequently decorated in situ with zeolitic imidazolate framework-67, resulting in carboxymethylated cotton gauze fabrics-zeolitic imidazolate framework-67 (CM-CGF-ZIF). The CGF, CM-CGF, and CM-CGF-ZIF were evaluated for potential kidney applications by removing uric acid and creatinine from mimic blood. The results showed that CM-CGF-ZIF had the highest adsorption of uric acid and creatinine. The maximum adsorption capacity of uric acid and creatinine was 164 and 222 mg/g for CM-CGF-ZIF, respectively, compared to 45 and 67 mg/g for CGF. CM-CGF-ZIF showed excellent antibacterial activity, good antifungal activity, low cytotoxicity, and a satisfactory level of blood compatibility.

Synergistic Elimination of Chlorophenols Using a Single-Atom Nickel with Single-Walled Carbon Nanotubes: The Roles of Adsorption, Hydrodechlorination, and the Electro-Fenton Process.

Electrocatalytic degradation enables the efficient treatment of chlorinated pollutants (COPs); however, its application has been significantly hindered by the large amounts of unsafe intermediate products. In this study, we present a single-atom nickel with single-walled carbon nanotubes (SWCNTs) as an electrochemical reactor for the complete elimination of chlorophenols. Distinct products and reductive mechanisms were observed for Ni-N-C compared to Cu-N-C. Ni-N-C incorporation has a novel degradation pathway for efficient chlorophenol degradation involving hydrodechlorination and the electro-Fenton process. Most importantly, the weak adsorption between the chlorophenols and the SWCNTs promoted their dechlorination by the attached active atomic hydrogen (H*) formed on the Ni-N-C. Meanwhile, the SWCNTs improved the reduction of O2 to H2O2, which was subsequently decomposed by Ni-N-C to form hydroxyl radicals (·OH) for phenol oxidation. As a result, the degradation rate of 4-chlorophenol was increased by 5 and 10 times compared with those of the Ni-N-C and SWCNTs alone, respectively. The first-order reaction rate constant was 2.7 h-1, and the metal mass kinetics constant was 1956.5 min-1g-1. Aromatic COPs containing benzene rings could be degraded, but chloroacetic acids could not. This study demonstrates a new design for multifunctional electrochemical degradation that functions via dechlorination and the ·OH activation mechanism.

Efficient degradation of haloacetic acids by vacuum ultraviolet-activated peroxymonosulfate: Kinetics, mechanisms and theoretical calculations

Efficient degradation of haloacetic acids (HAAs) is crucial due to their potential risks. This study firstly proposed vacuum ultraviolet - activated peroxymonosulfate (VUV/PMS) to remove HAAs (i.e., monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), dichloroacetic acid (DCAA), etc). VUV/PMS achieved 99.51 % MCAA and 63.29 % TOC removal within 10 min. Electron paramagnetic resonance (EPR), quenching and probe experiments demonstrated that •OH was responsible for MCAA degradation. MCAA degradation followed pathways of dehalogenation (major) and decarboxylation (minor). VUV/PMS showed application potential under various reaction parameters. Broad spectrum of VUV/PMS on various HAAs was further explored. Chlorinated HAAs (Cl-HAAs) were primarily degraded by oxidation reactions, while brominated HAAs (Br-HAAs) by direct VUV photolysis. The density functional theory-based calculations (DFT) revealed that reaction rates of HAAs correlated with the highest occupied molecular orbital (HOMO) and energy gap (ΔE), indicating that HAAs degradation depends on their chemical structures. The Fukui function (f0 values) and bond length showed vulnerability of the halogen atom in Cl-HAAs and C–Br bond in Br-HAAs. Overall, this study provides an in-depth perspective on the oxidation performance and mechanism of HAAs using VUV/PMS. It not only demonstrates a green and efficient method but also inspires new strategies for HAAs remediation.

Phosphotungstic Acid-Supported Hercynite: A Magnetic Nanocomposite Catalyst for the Selective Esterification of Chloroacetic Acid.

This study presents the synthesis and characterization of a novel phosphotungstic acid-functionalized hercynite@SiO2 magnetic core-shell through a three-step procedure. The characterization involved various analyses including Fourier-transform infrared spectroscopy, P-XRD, TGA-DSC, EDAX, inductively coupled plasma optical emission spectroscopy, elemental mapping, scanning electron microscopy, transmission electron microscopy, and value stream mapping. The catalytic performance of the hercynite@SiO2-PTA nanomagnetic composite was examined in the esterification of chloroacetic acid. Results indicate that the developed procedure enables the production of chloroacetic acid esters using a wide range of primary, secondary, and tertiary aliphatic and aromatic alcohols with good to excellent yields and high selectivity. The significance of this work lies in its straightforward synthesis method, minimal time requirement, reduced utilization of hazardous chemicals, and cost-effectiveness. Additionally, the catalyst exhibited magnetic recyclability for up to five cycles with negligible loss in activity. Notably, the synthesized catalyst demonstrated nontoxicity and environmental friendliness.

Remediation of water containing lead(II) using (3-iminodiacetic acid) propyltriethoxysilane graphene oxide

A novel chelating adsorbent based on (3-iminodiacetic acid) propyltriethoxysilane graphene oxide (IAT-GO) has been developed, showing exceptional promise for capturing lead. IAT-GO is made by combining a high-surface-area graphene oxide with a specially designed chelating ligand, which can selectively and efficiently remove lead. The synthesis of IAT-GO involves a two-step progression. In the first step, covalent bonds form between graphene oxide and (3-aminopropyl)-triethoxysilane (AT) through hydrolysis, condensation, and epoxide ring opening reactions. In the second step, nucleophilic substitution reactions occur between the primary amines and chloroacetic acid (CAA). A comprehensive suite of characterization techniques, including XPS, UV–Vis, XRD, Raman, FTIR, TEM, and SEM, provides detailed insights into the IAT-GO adsorbent's chemical composition and physical form, elucidating its intricate structure and morphology. Optimizing the experimental conditions for using the adsorbent material to remove Pb(II) ions from contaminated water revealed a maximum adsorption capacity of 124.0 mg/g at pH 5 and 30 min. The IAT-GO displays high selectivity for Pb(II) in a mixture of six metal ions containing 100 ppm of each one. Moreover, the IAT-GO shows 100% removal of Pb(II) for concentrations lower than 50 ppm. The excellent fit of the experimental data with the Langmuir adsorption isotherm and pseudo-second-order kinetic models (R2 > 99%) indicates that Pb(II) ion uptake onto the IAT-GO surface occurs via the monolayer formation of mercury ions. IAT-GO demonstrates exceptional potential as an innovative adsorbent for lead-contaminated water. Nitric acid (0.4 M) effectively regenerates the material, while its reusability remains impressive even after five cycles (> 97% removal efficiency). Therefore, this study highlights the development of a groundbreaking material, IAT-GO, with exceptional potential for remediating lead-contaminated water. Its high efficiency, selectivity, reusability, and cost-effectiveness make it a promising candidate for real-world applications.

FACILE SYNTHESIS OF CARBOXYMETHYL CELLULOSE (CMC) FROM AGRICULTURAL RESIDUES

Cellulose derivative products, such as carboxymethyl cellulose (CMC), which are used in the food, cosmetics, and pharmaceutical industries, but still rely on cotton-derived cellulose, can be made from oil palm fruit empty bunches (OPEFB) and rice straw. This study examined how sodium monochloroacetic acid (NaMCA) concentration (3, 6, and 9 g) affected the simple synthesis and characteristics of CMC from OPEFB and rice straw cellulose. OPEFB-derived CMC produced with NaMCA (9 g) had the lowest of brightness, while rice straw CMC was brighter. NaMCA modifications altered the onset temperature (Tonset), but not maximum degradation temperature (Tmax), according to thermal analysis. The onset temperatures of OPEFB and rice straw CMC were 40–62 °C and 67–183 °C, respectively. Commercial CMC has an onset temperature of about 27 °C. The EDX analysis showed that rice straw CMC had a higher degree of substitution (DS) of 0.34–1.37 than OPEFB CMC, which had 0.30-0.70. Oil palm empty fruit bunch (OPEFB) cellulose and rice straw cellulose offer a viable carboxymethyl cellulose (CMC) alternative. This process turns agricultural waste into valuable products and enables for their usage in numerous applications.

A green recyclable process for selective recovery of Li and Fe from spent lithium iron phosphate batteries by synergistic effect of deep eutectic solvent and oxygen

This work designs a new method for recovering spent LiFePO4 cathode materials, aiming to address issues with traditional hydrometallurgy processes such as complex operations, low lithium recovery rates, and high wastewater discharge. The method involves using a deep eutectic solvent (DES) composed of chloroacetic acid and ethanol, and oxygen as an oxidant, for the cooperative leaching of LiFePO4 powders. Based on the acidic nature of the DES and the oxidizing properties of oxygen, LiFePO4 was undergone an in-situ transformation into solid FePO4, while 100% of lithium was dissolved in the DES with high selectivity. The FePO4 product can be recovered by filtration, and the addition of oxalic acid to the filtrate allows for lithium recovery. Importantly, the structure of the DES remained unchanged after use, allowing for three recycling cycles without a significant decrease in LiFePO4 recovery efficiency. This process is environmentally friendly, with no generation of acidic or alkaline wastewater, and boasts high metal recovery rates, showcasing its huge potential for application.

Effective inhibition of chloride ion interference in photocatalytic process by negatively charged molecularly imprinted photocatalyst: Behavior and mechanism

The ubiquitous chloride ions (Cl−) in water seriously interfere with pollutant oxidation and inevitably generate undesirable chlorinated byproducts. In this study, we report for the first time that a negatively charged molecularly imprinted photocatalyst (MIP) can effectively inhibit Cl− interference and suppress the production of chlorination byproducts (the yield of chloroacetic acid was only 16 % of the bare photocatalyst system) while ensuring efficient degradation of target pollutants, thereby greatly improving the safety of the pollutant degradation process. Taking antibiotics as target pollutant, we investigated the mechanism of action of MIP by comparing the antibiotic degradation pathways, fate of photogenerated active species and production of reactive chlorine species (RCS) in the MIP and bare photocatalyst system. The mechanism by which MIP inhibits Cl− interference was mainly based on a synergy between electrostatic repulsion and steric hindrance induced by the specific capture of antibiotics in imprinted cavity, which effectively suppressed the production of RCS and hindered the participation of RCS in antibiotics degradation. In addition, MIP showed good compatibility with common cations, anions and organic matter, and performed well within a broad pH range in various water environments. Thus, the negatively charged MIP provides a feasible approach for the safe and efficient removal of pollutants in Cl− containing water.

Facile synthesis of carboxymethyl cellulose from Indonesia's coconut fiber cellulose for bioplastics applications

AbstractCoconut fibers contain many lignocellulosic components; therefore, they have the potential to be used as cellulose‐based materials. This study aims to synthesize carboxymethyl cellulose (CMC) for bioplastic applications from coconut fiber cellulose obtained from South Tangerang, Indonesia. The isolation of cellulose was conducted in two key stages: alkaline treatment using a delignification reactor and bleaching with hydrogen peroxide (H2O2). The facile synthesis of CMC involved two important steps: alkaline treatment and carboxymethylation of isolated cellulose. The yield of cellulose isolated from coconut fiber was 16.39% for biomass and 64.84% for delignification products. The cellulose produced exhibited a crystallinity index (C.I.) of 89%. The yield of CMC was 14.67%, with a C.I. was 56.66%. The CMC obtained was categorized as having a medium molecular weight of 249,048 Da with a polymerization degree of 1046. Cellulose starts to decompose at a temperature interval of 292.05–381.45°C, whereas CMC decomposes at a lower temperature interval of 245.42–299.73°C. Thermochemical calculations were conducted by using the density functional theory (DFT), confirming a spontaneous reaction with a Gibbs free energy of −5.25 kJ mol−1. Bioplastics were fabricated in two stages: blending with carboxymethyl chitosan (CMChi) and plasticizing with glycerol. The addition of CMCh increased the C.I. and tensile strength, while the addition of glycerol to CMC/CMChi (80/20) blend‐based bioplastic reduced the C.I. and tensile strength, but enhanced the relative contact angle.Highlights Cellulose was isolated from coconut fibers through a two‐stage process involving delignification and bleaching; Carboxymethyl cellulose was synthesized by reacting the cellulose of coconut fibers with monochloroacetic acid in isopropanol with NaOH as the catayst; The optimum condition for achieving the highest elongation at break among the blending compositions was found in the CMC/CMChi (80/20) blend bioplastic; Adding up to 30 wt% glycerol decreased the tensile strength and increased the elongation at break; The addition of glycerol enhanced the hydrophobic properties of CMC/CMCh blend‐based bioplastics.