Chloroacetic Acid Research Articles

A Flexible Self-Supported Silver Wire with Nanoporous Skeleton for Electrochemical Sensing of Trichloroacetic Acid

The content of chloroacetic acid in water is mandatory, so rapid and accurate detection is of great significance for environmental health. Silver has a strong specific interaction with chloridion and its three-dimensional interconnected ligaments are proved to have higher activity. Herein, a self-supported nanoporous skeleton was constructed on the surface of silver wire by directly electrochemical alloying in ZnCl2–glycol solution at 140 °C and subsequently dealloying in sulfuric acid solution. AgZn and AgZn3 alloys are formed by electrodeposition process, and the nanoporous skeleton of elemental silver is formed after dealloying. The interconnected ligaments are uniform and the pore size is about 10–200 nm. The cyclic voltammetry showed that the self-supported nanoporous skeleton of the silver wire electrode exhibited high electrocatalytic activity for trichloroacetic acid. Detected by chronoamperometry, the results show that the detection limit is 70 nM (S/N = 3) in the concentration range of 0.14–549 μM, and the sensor has high sensitivity, good reproducibility and anti-interference. And by detecting the recovery rate of trichloroacetic acid in the tap water, river water and industrial wastewater, the sensor proves the practicality of the prepared electrode.

One Pot Synthesis, Crystal Structure, Hirshfeld Studies, Docking Simulation and Antimicrobial Efficacy Assay of New Fused/Substituted Pyrazolinyl–Thiazolidinyl–Indolone Triheterocyclic Hybrid Scaffolds

In this present investigation, a new series of functionalized hybrid compounds containing three bioactive triheterocyclic templates, pyrazolines, thiazolidinones, and indolones are designed and synthesized via multicomponent, one-pot reaction of 3-(4-chlorophenyl)-5-[4-(propan-2-yl)phenyl]-4,5-dihydro-1H-pyrazole-1-carbothioamide with various substituted isatin derivatives and chloroacetic acid in the presence of fused sodium acetate and glacial acetic acid viz ring closure mechanism followed by dehydration. The formation of new scaffolds 4–7(a–c) is evidenced by analytical and spectral studies. The single-crystal X-ray diffraction study supported the molecular structure of compound 4a as a triclinic crystal system with a P space group and Z = 2. Interestingly, the compound is crystallized with two molecules (A/B) and one water molecule in the asymmetric unit, and the crystal packing is stabilized by intra and intermolecular hydrogen bonds. To quantify the percentage of intermolecular contacts and electrostatic potential distribution in crystal packing, Hirshfeld surface analysis was performed. All the compounds were screened for their preliminary antimicrobial activity against a panel of bacterial and fungal strains. The newly synthesized compounds exhibited fairly encouraging in vitro antibacterial activity, so the validation of the potent compound was done by docking against the antibacterial target Escherichia coli FabH (PDB: 5BNS). The virtual screening is focused on ADME and drug-likeliness properties to identify their putative ligand-protein interactions using Schrödinger software.

Syntheses and Solid-State Characterizations of N-Alkylated Glycine Derivatives

Seven N-alkylated glycine derivatives were prepared and characterized using single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis. Chloride salts, H2EtGlyCl, H2(n-PrGly)Cl and H2(i-PrGly)Cl were prepared by aminolysis of chloroacetic acid with respective alkylamine. Nitrate salts, H2EtGlyNO3, H2(i-PrGly)NO3, H2(n-PrGly)NO3 and zwitterionic compound H(n-PrGly)·1/3H2O were prepared using ion exchange reactions from corresponding chloride salts. In all the N-alkylated glycine chloride salts, two N-alkylglycinium cations and two chloride anions were connected into centrosymmetric dimers that were additionally hydrogen bonded into endless chains. In the nitrate salts, 2D networks of different topologies were formed through hydrogen bonds between nitrate anions and N-alkylglycinium cations. In compound H(n-PrGly)·1/3H2O, the zwitterionic N-(n-propyl)glycines and water molecules of crystallization were connected into the 3D hydrogen bond networks. Chloride salts have significantly more H⋯H and O⋯C contacts than nitrate salts. All chloride salts decompose in endothermic, while nitrate salts decompose in exothermic thermal events.

Synthesis of sonochemical chloroacetated natural rubber and its potential use in passenger car tire tread

This article describes the preparation of chloroacetated natural rubber (CNR) through the epoxidation of natural rubber (NR) latex with performic acid, followed by the reaction with chloroacetic acid. Ultrasound waves were utilized to accelerate the epoxidation reaction. The CNR samples obtained at various epoxidation durations were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, and differential scanning calorimetry techniques. Results showed that the chloroacetate content in CNR increased with increasing epoxidation time, i.e., the chloroacetate contents were 17.4, 18.5, and 19.7% at epoxidation times of 30, 45, and 60 min, respectively. The prepared CNR samples were then employed to replace NR in silica-filled tire tread compounds based on a 70/30 solution styrene butadiene rubber (SSBR)/NR blend. It was found that, compared with NR, CNR provided significantly higher rubber-silica interaction, leading to improved mechanical and dynamic properties. Such replacement not only reduced heat build-up and rolling resistance, but also increased the wet grip index, which is highly beneficial for the production of high-performance passenger car tires. It could be observed that the improvements in rubber properties and tread performance were more obvious when the chloroacetate content of CNR was increased, probably due to the enhanced rubber-filler interaction, as demonstrated by the increased bound rubber content.

Extraction of rare earth elements from monazite leach liquor using functionalized chitosan sorbents derived from shrimp waste

With the growing need for high-purity rare-earth elements (REEs), the separation of these REEs has received much attention recently. The objective of this research is to produce chitosan from shrimp waste, then modify it with different functionality, and investigate the adsorption properties of chitosan adsorbents towards La(III) ions. First, from shrimp waste, chitosan (ch) with a significant degree of deacetylation, purity, and solubility was produced. The purified chitosan was cross-linked with epichlorohydrin (ep), and then, it was modified with 3,6,9,12-tetraazatetradecane-1,14-diamine (HA) to produce polyaminated chitosan (HA@ep@Ch). The polycarboxylated/imine chitosan (CM@HA@ep@Ch) was obtained by treating polyaminated chitosan with chloroacetic acid in isopropyl alcohol. The chitosan adsorbents were characterized and applied for lanthanum recovery from synthetic and monazite leach liquor samples. The factors controlling the recovery process were studied and discussed. The performance of the adsorbents was achieved through equilibrium, dynamic, and isothermal studies. HA@ep@Ch and CM@HA@ep@Ch showed good performance for lanthanum recovery with a maximum capacity of 114.52 and 141.76 mg/g at 330 K, respectively. The isotherm parameters refer to the monolayer of lanthanum adsorbed into the adsorbents through chelation and ion exchange mechanisms. A 0.5-M HCl solution was found effective to elute 95.8% of the adsorbed lanthanum on HA@ep@Ch, and 93.4% of the adsorbed lanthanum on CM@HA@ep@Ch. The adsorbents showed greater selectivity in extracting La, Ce, Pr, Nd, and Sm (62–75%) from REE leach liquid compared to extracting other REEs (20–41%).

Synthesis and Antioxidant Activity of Some Benzoquinoline-Based Heterocycles Derived from 2-((3-Chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide

A new series of benzoquinoline-based heterocycles was synthesized utilizing the building block synthon, 2-((3-chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide via the condensation of 3-chlorobenzo[f]quinoline-2-carbaldehyde with thiosemicarbazide. The titled thiosemicarbazone scaffold was conducted with some carbon-centered electrophilic reagents such as acetic anhydride, chloroacetyl chloride, chloroacetic acid, 2-bromo-1-(3-nitrophenyl)ethan-1-one, 2-chloro-N-phenylacetamide, and dimethyl but-2-ynedioate to achieve triazolethione, imidazolone, thiazolidinone, and thiazole derivatives. In turn, the hydrazinolysis of this substrate did not proceed as expected but it afforded the azine derivative. The antioxidant activity screening of the produced compounds revealed that thiazole and triazolethione derivatives were the most potent.

Synthesis, spectroscopic, DFT calculations, biological activity, SAR, and molecular docking studies of novel bioactive pyridine derivatives

Enaminonitrile pyridine derivative was used as a precursor for preparation of fourteen heterocyclic compounds using both conventional thermal and microwave techniques. Diverse organic reagents, such as chloroacetyl chloride, acetic anhydride, chloroacetic acid, carbon disulfide, p-toluene sulfonyl chloride, maleic anhydride, phthalic anhydride, were used. The chemical formulae and structures of isolated derivatives were obtained using different analytical and spectroscopic techniques such as IR, 1H-, 13C-NMR as well as mass spectrometry. The spectroscopic analyses revealed diverse structure arrangements for the products. Molecular structure optimization of certain compounds were performed by the density functional theory (DFT/B3LYP) method and the basis set 6–31 G with double zeta plus polarization (d,p). The antimicrobial inhibition and the antioxidant activity of the reported compounds were screened. Compounds 5, 6, 11 and 13 exhibited the highest antibacterial inhibition, while compound 8 gave the highest scavenging activity (IC50 43.39 µg/ml) against the DPPH radical. Structure–activity relationship of the reported compounds were correlated with the data of antibacterial and the antioxidant activity. The global reactivity descriptors were also correlated with the biological properties of compounds. The molecular docking studies of reported compounds were investigated, and the analysis showed that the docked compounds have highly negative values for the functional binding scores. The binding interaction was found to be correlated with the substituent fragments of the compounds.

Study on synthesis of carboxymethyl cellulose from pineapple leaf waste and its potential applications as a thickener

In this study, cellulose and hemicellulose were successfully extracted from pineapple leaf waste at yields of 58.8 and 16.1% by dried weight, respectively. Carboxymethyl cellulose (CMC) was synthesised from pineapple leaf cellulose by an esterification process using sodium hydroxide (NaOH) and monochloroacetic acid (MCA) with isopropanol as the supporting medium. Preparation of CMC was investigated by varying three free factors, namely, NaOH concentration, MCA dose, and cellulose size. The carboxymethylation process was optimised to produce CMC with differing degrees of substitution (DS). The highest DS of CMC (0.86) was obtained with 15% (w/v) NaOH solution, 0.6 g of MCA/g cellulose, and 50 μm cellulose. The obtained CMC were characterised by FTIR spectroscopy, SEM images and XRD diffractions. Moreover, the thickening performance of obtained CMC was also determined. The influence of the CMC’s molecular weight and degree of substitution on the viscosity of 1% (w/v) aqueous solution was tested. The experimental results suggest that the viscosity of the solution increases with increasing molecular weight and degree of substitution of CMC.

Occurrence, formation, and proteins perturbation of disinfection byproducts in indoor air resulting from chlorine disinfection

Increased amounts of chlorine disinfectant have been sprayed to inactivate viruses in the environment since the COVID-19 pandemic, and the health risk from chemicals, especially disinfection byproducts (DBPs), has unintentionally increased. In this study, we characterized the occurrence of haloacetic acids (HAAs) and trihalomethanes (THMs) in indoor air and evaluated their formation potential from typical indoor ingredients. Subsequently, the adverse effect of chloroacetic acid on A549 cells was depicted at the proteomic, transcriptional and silico levels. The results revealed that the total concentrations of HAAs and THMs ranged from 1.46 to 4.20 μg/m3 in ten indoor environments. Both classes of DBPs could be generated during the chlorination of prevalent terpenes by competing reactions, which are associated with the volatile state of indoor ingredients after disinfection. The C-type lectin receptor signaling pathway and cellular senescence were significantly perturbed pathways, which interfered with the development of lung fibrosis. The negative effect was further investigated by molecular docking and transcription, which showed that HAAs can interact with four C-type lectin receptor proteins by hydrogen bonds and inhibit the mRNA expression of related proteins. This study highlights the potential secondary biological risk caused by intensive DBPs generated from chlorination and draws our attention to the potential environmental factors leading to chronic respiratory disease.

Treatment of carbocysteine wastewater by bipolar membrane electrodialysis: From lab-to pilot-scale

Carbocysteine (H2ccys) wastewater, which contains H2ccys, chloroacetic acid, and ammonium chloride, can pose significant risks to the environment. In this study, a novel strategy was proposed for treating H2ccys wastewater by bipolar membrane electrodialysis (BMED) to realize resource recovery. The migration and coexistence mechanism of organic/inorganic ions in wastewater were investigated in lab-scale experiments. The results indicated that the desirable migration of inorganic ions, such as NH4+ and Cl− ions, in the feed compartment were dominant. The undesirable migration of organic molecules, such as ClCH2COOH and H2ccys, could be managed through precise control of the BMED reaction process. To optimize the energy efficiency and thermal effect occurred in the pilot-scale, a two-stage BMED process was designed for treating H2ccys wastewater. The results revealed that BMED produced 1.33–1.63 M of HCl and 2.62–2.88 M of NH3·H2O, and removed 90 wt% of NH4Cl from H2ccys wastewater. Meanwhile, the thermal effect of the slot at the outermost acid compartment decreased from 3.32 W in the one-stage BMED process to 0.10 W in the two-stage BMED process during the pilot-scale tests. The current efficiency of the two-stage BMED process for the acid/base production and feed desalination in the pilot-scale tests increased and its energy consumption decreased compared with the lab-scale tests. Moreover, the BMED rrecycling route showed that a closed loop can be realized in the treatment of H2ccys wastewater, and its economic assessment showed that applying BMED to the treatment of H2ccys wastewater have economic benefits. These findings illustrated the feasibility of this novel strategy for treating H2ccys wastewater and laid a solid foundation for its industrialization.

New thieno[2,3-b]pyridine-based compounds: Synthesis, molecular modelling, antibacterial and antifungal activities

New thieno[2,3-b]pyridine clubbed various thiazole ring systems were synthesized by the reaction of 2-(1-(3-amino-4,6-dimethylthieno[2,3-b]pyridin-2-yl)ethylidene)hydrazine-1-carbothioamide with chloroacetone, phenacyl chloride, and chloroacetic acid. The molecular modeling of the synthesized compounds using DFT/B3LYP methodology revealed that all have a low HOMO and LUMO energies, −4.85 - −5.52 and −2.79 - −3.62, respectively, where the compound 10 has the highest values. The targeting thienopyridine analogues with various thiazole moieties 3–10 was assessed in order to create new antimicrobial agents and compared with ampicillin, gentamicin and miconazole as reference antibacterial and antifungal drugs. Compounds 8–10 exhibited potent antimicrobial activity against Gram positive S. aureus, Gram Gram negative E. coli bacteria, and C. albicans (antifungal), with IC50 (18.9 ± 0.63––24.3 ± 0.74 µg/mL), (14.2 ± 0.41––19.5 ± 0.64 µg/mL), and (19.2 ± 0.58–––23.4 ± 0.65 µg/mL), respectively. Furthermore, Molecular docking stimulation on MOE program was applied to expect the effect and interactions of the newly thienopyridine analogues and E. coli DNA gyrase B as it expressed by PDB ID: 1AJ6.

Solvent-less carboxymethylation-induced electrostatic crosslinking of chitosan

The successful N-carboxymethylation and concomitant crosslinking of solid chitosan upon heating its mixture with solid monochloroacetic acid, without the use of solvents or catalysts, is reported. The N-carboxymethylation was confirmed through the analysis of the partially depolymerized product using NMR spectroscopy, as well as a control reaction with lysine. This transformation was facilitated by the nucleophilic nature of the free amine group in the repeating unit of chitosan, which possesses lone pair of electrons capable of attacking the carbon center bearing the leaving group and displacing the leaving group in a concerted manner. The crosslinking, on the other hand, was established by the observed insolubility in aqueous acidic solutions, even when subjected to prolonged heating at 60 °C. This crosslinking occurs due to the electrostatic interactions between the carboxylate groups and the adjacent ammonium groups, as supported by evidence from FTIR spectroscopy and a control reaction involving ethyl chloroacetate. The resulting crosslinked carboxymethyl chitosan demonstrated its usefulness in the adsorption of methyl orange and fluorescein, as well as functioning as an organic catalyst for aza-Michael addition, Hantzsch reaction, and substituted perimidine synthesis.

Ultrasonic/cellulase-assisted extraction of polysaccharide from Garcinia mangostana rinds and its carboxymethylated derivative

Response surface methodology was selected to explore the ultrasonic-assisted cellulase extraction conditions of Garcinia mangostana rind polysaccharides (GMRPs), and the optimum values of each condition were as follows: ratio of raw material to liquid of 1:50 g/mL, ultrasonic time of 40 min, enzyme concentration of 4 %, and ultrasonic power of 179 W. Based on the above conditions, the average extraction rate of GMRPs was 15.56 %. GMRPs were modified by carboxymethylation, and the relationship between the amount of chloroacetic acid and the substitution degree of carboxymethylated derivative was compared. Based on the results of single factor experiment, it was shown that the amount of chloroacetic acid significantly affected the degree of substitution of derivative products. The above research provides some valuable theoretical references for the preparation of GMRPs and its carboxymethylation products.

Synthesis of S-(5-aryl-1,3,4-oxadiazol-2-yl) O-alkyl carbonothioate and alkyl 2-((5-aryl-1,3,4-oxadiazol-2-yl)thio) acetate, and their antimicrobial properties

The S-(5-aryl-1,3,4-oxadiazol-2-yl) O-alkyl carbonothioate (4-9) and the alkyl 2-((5-aryl-1,3,4-oxadiazol-2-yl)thio) acetate (10-15) were synthesized by interaction of 5-aryl-1,3,4-oxadiazole-2-thiones with alkyl esters of chloroformic acid and chloroacetic acid. The yields of target compounds (7-9) obtained with isobutyl chloroformate were 69-73%, compounds (4-6) with propyl chloroformate - 74-79% and compounds (10-15) with alkyl esters of chloroacetic acid - 86-92%, respectively. The structures of the synthesized compounds were confirmed by IR, UV, 1H and 13C NMR spectra. The antibacterial and antifungal activities of these compounds were investigated. The results of in vitro antimicrobial activity tests showed that S-(5-phenyl(2-chlorophenyl)-1,3,4-oxadiazol-2-yl) O-propyl carbonothioate (4-5) and S-(5-phenyl(2-chlorophenyl)-1,3,4-oxadiazol-2-yl) O-isobutyl carbonothioate (7-8) exhibited weak, but selective antibacterial activity against gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus). At the same time, no activity was shown by compounds with two chlorine atoms in the aromatic ring (13-15) and alkyl 2-((5-aryl-1,3,4-oxadiazol-2-yl) thio) acetate (10-15).

Synthesis and Characterization of New 2-amino-5-chlorobenzothiazole Derivatives Containing Different Types of Heterocyclic as Antifungal Activity

Nine new compounds of 2-amino-5-chlorobenzothiazole derivatives were synthesized. These new compounds were formed through the reaction of 2-amino-5-chlorobenzothiazole 1 with ethyl chloroacetate and KOH, which gave an ester derivative 2, followed by refluxing compound 2 with hydrazine hydrate to afford hydrazide derivative 3. The reaction of compound 3 with CS2 and KOH gave 1,3,4-oxadiazole-2-thiol derivative 4, and then the reaction of compound 2 with thiosemicarbazide to produce compound 5 then treated it with 4%NaOH led to ring closure to provide 1,2,4-triazole-3-thiol derivative 6. The reaction of 2-amino-5-chlorobenzothiazole1 with chloroacetic acid gave 7 followed by refluxing the latter compound with ortho amino aniline giving benzimidazole derivative 8. Azomethine 9 was synthesized over 2-amino-6-chloro-benzothiazole with bromobenzaldehyde, the last compound 9 was converted to a thiazolidinone derivative 10 through the reaction of compound 9 with 2-mercaptoaceticacid. The prepared derivatives were established by using FT-IR, 1H-NMR spectroscopy, elemental analysis C.H.N. and physical properties. Entirely compounds were examined for their anti-fungal action against Candida glabrata and Aspergillus niger, and the results revealed that some compounds showed a good measurable activity comparing with fluconazole as stander drug.

Application of Chitosan and Its Derivatives as Bioflocculants for Iron and Turbidity Removal from Filter Backwash Water

The present study aimed to investigate the potential application of chitosan (CS) and its two derivatives, dialdehyde chitosan (DCT) and carboxymethyl chitosan (CMC), as new flocculants in the purification of filter backwash water. The main objective of the work was to remove the disadvantages and inconveniences associated with using synthetic flocculants, mainly based on polyacrylamide, by using biodegradable and non-toxic biopolymer flocculants. The chitosan derivatives were obtained in the process of the chemical modification of this polysaccharide. CS was oxidated with periodate in acetic acid solution to obtain DCT with a degree of substitution (DS) of 44.29%. For the CMC synthesis, after the alkaline activation of chitosan, the solution was treated with monochloroacetic acid (MCA) at 60 °C for 3 h, leading to carboxymethylated chitosan formation with a DS of 49.55%. Characterizations of the flocculants using Fourier transform infrared (FT-IR) spectroscopy, 13C nuclear magnetic resonance (13C NMR) spectroscopy, and an elementary analysis confirmed the successful modification of the chitosan. The morphology and thermal stability of the samples were investigated using scanning electron microscopy (SEM) and a thermogravimetric analysis (TGA), respectively. Moreover, the biopolymer materials were studied in a series of flocculation jar tests for filter backwash water samples collected at a water treatment plant (WTP) in Kutno, Poland. CMC turned out to be a particularly effective agent in an optimal amount of 0.2 mg/L, achieving nearly 99% iron removal and 98.26% turbidity removal efficiency rates, which indicates that chitosan–based materials can be ecological alternatives for polyacrylamide flocculants, effectively removing the impurities of iron ions.

Aminocoumarin derivatives grafted on graphene oxide - new antimicrobial agents to combat the resistance of Mycobacterium tuberculosis and ESKAPE pathogens

Two hybrid materials, based on 7-amino-4-(trifluoromethyl)coumarin and 7-amino-4-methyl-coumarin that attach covalently to graphene oxide (GO) have been synthesized in two steps: i) increasing the number of carboxyl groups required for functionalization with aminocoumarin derivatives by derivatization of the hydroxyls groups with chloroacetic acid, transforming GO into GO-COOH material; ii) activation of carboxylic groups using the carbodiimide-promoted reaction. The obtained composites were characterized by numerous methods that highlighted their successful obtaining. The antimicrobial activity was evaluated on resistant Mycobacterium tuberculosis strains, as well as on ESKAPE pathogens ((Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) in planktonic and biofilm growth states. The biocompatibility of the materials has been assayed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay as well as by measuring the level of nitric oxide/total reactive oxygen species and superoxide release in treated cells. The results have shown that materials exhibited improved inhibitory activity against resistant M. tuberculosis strains in comparison with GO, but also against planktonic and adherent strains. Also, the tested composites have been proved to be biocompatible on the MRC-5 fibroblast cells, demonstrating their promising potential to develop novel agents effective against multidrug resistant pathogens, including M. tuberculosis, as well as by the activation of a pro-inflammatory and of an oxidative response in the mammalian cells.

Synthesis and fluorescent property of carboxymethyl chitosan with different degrees of carboxymethylation and its application for fluorescence turn-on detection of Cd(II) ion

Recently, carboxymethyl chitosan (CMCS) has proved to be an intrinsically fluorescent material with aggregation-induced emission characteristic. In order to elucidate the influence of CMCS's chemical structure and solution behavior on its fluorescent intensity, two series of CMCS with different degrees of carboxymethylation (DCM) are synthesized by adjusting the mass ratio of monochloroacetic acid and sodium hydroxide to chitosan at various reaction temperature and time, and then characterized using Fourier-transform infrared spectroscopy and nuclear magnetic resonance. Their solution behaviors at different pH values are studied via zeta potential and ultraviolet-visible measurements. The data reveal that the isoelectronic point (IEP) of a CMCS decreases with increasing DCM, and all the CMCSs have good water solubility at pH range below their IEPs. Fluorescence spectra indicate that a CMCS shows the highest fluorescent intensity in a slightly acidic environment next to its IEP, and the photoluminescence of a CMCS solution increases significantly after heat treatment above T = 70 °C. Furthermore, we compare for the first time the use of heated CMCS solutions for the fluorescence turn-on detection of cadmium ion in pure and tap water, respectively. The limit of detection is found to be ca. 1 μM for the Cd2+ in pure water.

Isolation, Modification and Characterization of Cellulose from Corn Husk Waste of Puncak‐Bogor

AbstractCellulose and its derivatives are important industrial raw materials for their advantages, including abundance, biodegradable, environmentally friendly, biocompatible, and good mechanical and thermal properties. This study aims to isolate and modify cellulose from corn husk waste of Puncak‐Bogor, Indonesia for improving the characteristics and usability of corn husk cellulose. The cellulose of corn husk was isolated with the delignification and bleaching process, by using sodium hydroxide (NaOH) and hydrogen peroxide (H2O2), respectively. The modification of cellulose was carried out using alkaline and etherification stages with monochloroacetic acid (MCA) in an isopropyl alcohol solvent. The presence of a peak at 898 cm−1 on the bleaching product confirmed the β‐(1,4)‐glycosidic bond of pure cellulose, while the peak at 1612.49 cm−1 on the modified cellulose product confirmed the carbonyl group of carboxymethyl cellulose. Cellulose isolated from corn husk has a crystallinity index of 76.4 % (2nd bleaching product), while CMC is 29.97 %. Cellulose (2nd bleaching product) starts to decompose at 271.8 and finishes at 642.63 °C, while CMC shows a lower decomposition temperature of 248.47 and 628.17 °C. Based on the results, it can be concluded that cellulose and CMC from Puncak‐Bogor's corn husk waste were obtained through the isolation method and modification stages in this research, respectively.

Preparation and Properties of New Starch-based Ceramic Body Reinforcing Agent

In ceramic production, the finished product is often fragile and defective due to low green strength, which greatly affects the ceramic yield and the preparation of advanced ceramics. It is important to develop a ceramic body reinforcement agent with an obvious reinforcement effect, no impact on slurry properties, low cost, and simple preparation process. In order to solve the above problems and analyze the influence of modification conditions on the green body enhancement results, the properties of three common starches were compared and corn starch was modified by substitution method to prepare a novel starch-based ceramic green body enhancer. The structural characterization and enhancement effect of the modified corn starch prepared by infrared spectroscopy and X-ray diffraction analysis showed that the addition of starch-based ceramic green body enhancer made the green body enhancement rate reach 61% and the mildew resistance increase for more than 4 days. The best preparation conditions for modified starch were soluble corn starch 33.3 g, 85% ethanol solution 300 mL, sodium hydroxide 16.46 g, chloroacetic acid 26.6 g, and reaction at 40 °C for 2.5 h.