Water Absorption Enhancement of Sodium Poly Acrylate and Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) Based Hydrogel Mixtures

Introduction: Hydrogels are hydrophilic polymers which are cross-linked to form three-dimensional structures, which can absorb, swell and retain huge amounts of water or aqueous fluids. Objective: This paper reports the preparation and characterisation of Poly(2-Acrylamido-2-Methylpropane Sulphonic Acid) (PAMPS) hydrogel with different crosslinking intensities. Methodology: 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) monomer was purchased from Alfa Aesar Company as reagent grade. It was used as received (>98% purity) without any further purification. PAMPS hydrogel was prepared by free radical crosslinking solution polymerization of AMPS in water at room temperature under a nitrogen blanket in cylindrical glass tubes. The characteristics of the obtained PAMPS hydrogel were compared with those of commercial sodium polyacrylates hydrogel. Results: It was found that decreasing the crosslinker weight improved the absorbance capacity but to a limit. The suggested reasons were discussed. The mixture showed higher absorbance rate than PAMPS, and bigger absorbance capacity than sodium polyacrylates. Conclusion: This paper investigates the effect of crosslinker ratio on the swelling capacity of PAMPS. It was found that as the crosslinking ratio decreases, the porosity of the hydrogel increases, thus improving the swelling capacity.

Removal of Carcinogenic Dyes Congo red (CR) and Bismarck brown Y (BBY) by Adsorption onto Reusable Hydrogels Derived from Acrylamide

Hydrogels of acrylamide (AM), acrylamide\ 2-acrylamido-2-methyl-1-propane sulphonic acid (AMS), and acrylamide\ 2-acrylamido-2-methyl-1-propane sulphonic acid\graphene oxide (AMSGO) were prepared as adsorbents to remove carcinogenic dyes Congo red (CR) and Bismarck brown Y (BBY) from aqueous solutions. Hydrogels were characterized using FSEM and XRD analyses. For both dyes, the synthesized hydrogels demonstrated high adsorption capability at near-neutral pH. Experimental adsorption data were analyzed using the Langmuir and Freundlich isotherm models. It was found that the Langmuir model was more suitable for the experimental data. Kinetic studies found that the pseudo-second-order model demonstrated the best fitting to the experimental data. In addition, thermodynamic studies suggest that the adsorption process was spontaneous and endothermic. The prepared hydrogels were regenerated and reused in four consecutive cycles and it could be applied to remove anionic dyes from aqueous solutions as an effective adsorbent.

Mitigation of free radicals and carbohydrate-linked enzymes by extracts and partitioned fractions of Elephantorrhiza elephantina (Burch.) Skeels root

Background: Elephantorrhiza elephantina (Burch.) Skeels is a medicinal plant used in folkloric medicine for the management of several metabolic and infectious diseases.Aim: This aim of this research study was to investigate the antioxidant and antidiabetic effects of extracts and partitioned fractions in order to validate its folkloric use.Setting: The plant material purchased from herb sellers in Qwaqwa township, authenticated at Department of Plant Science Qwaqwa herbarium, was evaluated in the same unit of the University of the Free State.Methods: The antioxidative and antidiabetic activities of extracts and fractions were assessed with 1,1-diphenyl-2-picrylhydrazyl, 2,2-azino-bis(3-ethylbenzothiazoline-6)-sulphonic acid, hydroxyl radicals, metal chelating agents, and α-amylase, as well as α-glucosidase inhibitions based on standard methods. The subfractions with considerable yields from the partitioned n-hexane fraction of the crude extract were subjected to gas chromatography-mass spectrometry analysis or profiling for possible compound identification.Results: The aqueous extract showed the most effective 1,1-diphenyl-2-picrylhydrazyl, hydroxyl radical and metal chelating activities judging by half-maximal inhibitory concentrations (IC50: 0.573, 0.059 and 1.937 mg/mL, respectively), whilst the ethanol extract revealed maximum activity (0.017 mg/mL) against 2,2-azino-bis(3-ethylbenzothiazoline-6)-sulphonic acid. However, the ethanol extract displayed the most potent alpha-amylase (0.346 mg/mL) inhibition, whilst the aqueous extract (0.363 mg/mL) was best against alpha-glucosidase. The modes of enzymes inhibition revealed that the aqueous extract displayed near-competitive inhibition against alpha-amylase and uncompetitive inhibition against alpha-glucosidase. Additionally, good antioxidative and antihyperglycaemic effects were established by the n-hexane fraction when compared with standards (gallic acid and acarbose). The GC-MS chromatogram of subfractions (4 and 9) from the n-hexane fraction afforded compounds, such as 2,4-bis (1, 1-dimethylethyl)-phenol, 9-octadecenoic acid (Z)-, methyl ester, dodecanoic acid and 1-methylethyl ester already established in the literature with potential pharmacological activities (antioxidant, anti-inflammatory, etc.).Conclusion: The research study provides evidence on the folkloric use and insights on the prospect of the plant as natural antioxidative and antidiabetic agents.

Different Mechanism and Efficacy of Dextran-Sodium Sulfate and 2,4,6-Trinitrobenzene Sulphonic Acid in Modeling Ulcerative Colitis in C57BL/6 Mice

Background and Aims: Dextran-sodium sulfate and 2,4,6-trinitrobenzene sulphonic acid are common modeling methods in studying ulcerative colitis. Little attention has been paid to the mechanism differences between the two approaches. Here, we aim to compare the mechanisms and efficacy of these two models and wish to provide fundamental proves for choosing ideal ulcerative colitis models. Methods: Dextran-sodium sulfate and 2,4,6-trinitrobenzene sulphonic acid were applied to induce the colitis in C57BL/6 mice for seven days. Body weight and disease activity index were assessed. Hematology was detected by routine blood test. Histopathology was analyzed by hematoxylin-eosin staining section. Enzyme-linked immunosorbent assay, Western blot and quantitative real-time PCR were used to detect the cytokines protein levels and mRNA levels. Flow cytometry were used to detect the cycles and subsets of splenic cells. Results: Dextran-sodium sulfate induced colitis in C57BL/6 mice showed higher acute immune activities, while 2,4,6-trinitrobenzene sulphonic acid induced colitis showed chronic immune activities with high platelet amounts and activation. Dextran-sodium sulfate is more suitable for modeling acute ulcerative colitis. On the contrary, 2,4,6-trinitrobenzene sulphonic acid is more appropriate for modeling chronic ulcerative colitis. Conclusions: Dextran-sodium sulfate treatment within 7 days in C57BL/6 mice is a suitable experimental model for studying human acute ulcerative colitis with immune response, fecal blood and acute pathogenic damage. Conversely, 2,4,6-trinitrobenzene sulphonic acid treatment within 7 days is more appropriate for studying human chronic ulcerative colitis with hypercoagulable state, IL-2 over-expression state and chronic pathogenic damage.

Fabrication and Characterization of Diclofenac Sodium Loaded Hydrogels of Sodium Alginate as Sustained Release Carrier

The aim of the current study was to fabricate naturally derived polymer based hydrogels for controlled release of diclofenac sodium (DS) for a long duration of time. In this research work, sodium alginate-co-poly(2-acrylamido-2-methyl propane sulphonic acid) (SA-co-poly(AMPS)) hydrogels were prepared by the free radical polymerization technique, where sodium alginate (SA) and 2-acrylamido-2-methyl propane sulphonic acid (AMPS) were used as the polymer and monomer while ammonium peroxodisulfate (APS) and N,N′-Methylene bisacrylamide (MBA) were used as the initiator and cross-linker, respectively. A swelling study was performed to determine the swelling index of developed hydrogels in both acidic (pH 1.2) and basic (pH 7.4) media and pH-independent swelling was observed due to the presence of AMPS. An in vitro release study was conducted to evaluate the percentage of drug released, and a high release of the drug was found at the higher pH of 7.4. Sol–gel analysis was performed to analyze the crosslinked and uncrosslinked part of the hydrogels, and results showed a rise in gel fraction as the composition of SA, AMPS and MBA increased while the sol fraction decreased and vice versa. This work demonstrated a potential for sustained delivery of diclofenac sodium by employing various concentration of SA, AMPS and MBA.

Novel sulphonic acid liquid crystal derivatives: experimental, computational and optoelectrical characterizations

A novel liquid crystal homologous series based on the benzene sulphonic acid moiety, namely (E)-4-((4-((4-(alkoxy)benzoyl)oxy)benzylidene)amino)benzenesulfonic acid (Sn), was synthesized and examined via different experimental and theoretical measurements.

Removal of Some Heavy Metals [Pb(II), Cd(II), Zn(II)] in Polluted Waters using Acid- Functionalized MCM-41 Mesoporous Materials: Adsorption Isotherm and Kinetic Studies

Acid functionalized mesoporous silica materials like sulphonic acid (SO3HMCM-41) and phosphotungstic acid (PWMCM-41) were synthesized by a simple co-precipitation method. These materials were characterized using XRD, SEM-EDS, FT-IR, BET surface area techniques. The mesoporosity was retained even after acid functionalization into MCM-41. There was a significant fall in the surface area (SBET, m2 g-1), on incorporation of sulphonic acid (-SO3H) and phosphorous, tungsten atoms into the MCM-41 material. SO3HMCM-41 was found to be more acidic than PWMCM-41 and MCM-41. Their performance was evaluated by conducting experiments on the removal of heavy metals like Pb(II), Cd(II), Zn(II) present in industrial wastewaters, with atomic absorption spectrophotometer (AAS). The required experimental factors were analyzed and it was observed that the removal of metals was more efficient with the acid-functionalized materials than with MCM-41. Freundlich adsorption isotherm and pseudo-first order kinetics have confirmed the validity of the results.