Effects of different polymerisation conditions using hybrid polymer on high turbidity suspensions

Purpose In this study, new hybrid polymers composed of Zinc chloride (ZnCl2), acrylamide and chitosan were prepared at different ratios and temperatures. The effects of pH and polymer dosage were examined for different polymers to observe their efficiency in the removal of turbid water. The polymers’ zeta potential, morphology, elemental composition and functional groups were also identified and studied. Design/methodology/approach The free-radical polymerisation process was executed in the presence of N, N’-Methylene bis-acrylamide and potassium persulphate in one molar acrylamide solution. ZnCl2 and chitosan (CO) were later introduced into the suspension under nitrogen gas flow. Ratio and temperature were varied during polymerisation. The hybrid polymer produced, termed Polyacrylamide + chitosan oligosaccharide + zinc chloride (PAMCOZ), was analysed using Fourier transform infra-red spectroscopy attenuated total reflectance and scanning electron microscope with energy dispersive X-ray. The hybrid PAMCOZ was experimented with in high turbid kaolin suspension using jar testing analysis to see its ability as a coagulant. Findings The coagulation process using PAMCOZ with a ratio of 11 (3:2) at 70°C surrounding temperature showed a 100% reduction at pH 4 with 50 mg/L of the polymer. The functional groups present in ratio 11 polymer were hydroxyl, carbonyl, amide and methyl groups. In addition, several elements were spotted on the surface of PAMCOZ, such as zinc (Zn), carbon (C), chlorine (Cl), nitrogen (N) and oxygen (O). The effect of pH also demonstrated that PAMCOZ was unfavourable in an alkaline turbid water environment. Research limitations/implications Due to the research methodology approach, the research results may lack actual wastewater application. Therefore, researchers are encouraged to test the hybrid coagulant on raw wastewater, such as pulp and paper mill effluent with a high turbidity value similar to this study. Originality/value The polymerisation between zinc chloride, acrylamide and chitosan has not yet been applied. The different ratios and effects of temperature were analysed on PAMCOZ to see the turbidity removal. PAMCOZ showed better turbidity removal in acidic conditions.

Synthesis and characterization of polypropylene glycol-graft-styrene

Grafting polymerization based on polypropylene glycol (PPG) and styrene (St) was synthesized with different composition of styrene using the free radical technique in the presence of potassium persulphate as an initiator. The grafted copolymers (PPG-g-St) used different styrene composition (65/15, 65/25, 65/35), respectively. The grafted copolymers were investigated through FTIR (Fourier-transform spectroscopy), Differential scanning calorimeter and thermogravimetric analyzer. FTIR showed new peaks at 1450 cm-1 and 1135 cm-1 due to the grafting process of St on PPG. Thermal stability of grafted copolymer increases by increasing the ratio of styrene, while Tg decreases by increasing the ratio of styrene.

Controlled drug release of levofloxacin from poly (acrylamide) hydrogel

Hydrogels are 3D polymer networks capable to absorb and release water or biological fluids. They are stimuli-responsive materials, which can show rapid volume changes with response to small changes in environmental parameters such as ionic strength, pH, and temperature. In this work, we performed a synthesis of Poly(acrylamide) hydrogel and tested for controlled release of levofloxacin hemihydrate as a model drug. We used sodium metabisulfite and potassium persulphate as free radical initiators to prepare hydrogel with methylenebisacrylamide as a crosslinker. Characterization of hydrogel was performed by TGA, SEM, and FT-IR. Swelling study and drug release were performed at pH 1.2 and 7.4 solutions, identical to the gastrointestinal fluid at 37°C (human body temperature) to examine possible site-specific drug delivery. UV-Visible spectrophotometer was used to measure the concentration of drug release. Results exhibited the pH and temperature-dependent drug release. The amount of drug release was found to be 17% and 99% in acidic and alkaline pH of 1.2 and 7.4, respectively, after 6 hours.

Synthesis and Characterization of Poly(acrylamide) Hydrogels as pH and Salt Sensitive Material

This work reports the synthesis of poly(acrylamide) hydrogel and its characterization. Hydrogel will be synthesized by a chemical cross-linking method using sodium metabisulfite and potassium persulphate as initiators with crosslinker methylenebisacrylamide. The synthesized hydrogels were examined by FT-IR, SEM and TGA to determine chemical interactions in the polymer network. Moreover, the swelling study explains that hydrogels swelling capacity and it depends on the concentration of the crosslinking agent. The pH, temperature and salt solutions will impact on swelling properties. In acid and base solutions, the swelling ratio order is as follows HCl < CH3COOH < HClO4 < NaOH and the swelling ratio order in salt solutions is as follows: NaCl > CaCl2 > AlCl3.

Fabrication of Magnetic Nanoparticles Integrated Carbon Matrix from Chrysopogon zizanioides Roots: Strong Dye Adsorption and Persulphate Assisted Photodegradation

Activated carbon with magnetic nanoparticles was prepared from the roots of Chrysopogon zizanioides by impregnating the biomass with Fe3+ followed by carbonization in a muffle furnace. To assist the carbonization process, Zn2+ ions were also taken along with ferric ions during impregnation. The pHZPC, density of surface functional groups, surface acidity constants and advanced characterizations like FT-IR, N2 adsorption-desorption isotherms, SEM with EDAX, DLS, XRD and VSM analysis were carried out. The adsorption and natural sunlight induced photooxidation of two cationic dyes, namely, methylene blue and rhodamine B in presence of potassium persulphate were studied by varying parameters like time, dye concentration, pH of the dye solution, amount of magnetic activated carbon and concentration of persulphate ions. The adsorption capacities of methylene blue and rhodamine B were found to be 5.97 and 0.96 mg/g, respectively. Photocatalytic oxidation of the dyes was very rapid in the presence of persulphate with the observed rate constants being 5.3 × 10–3 min–1 for methylene blue and 13.0 × 10–3 min–1 for rhodamine B. The magnetic activated carbon is found to be effective even after five successive degradation experiments.

Water Interactions in Hybrid Polyacrylate-Silicate Hydrogel Systems

Hybrid polyacrylate-silicate hydrogels were obtained in the presence of N,N′-methylenebisacrylamide (NNMBA) as the cross-linking monomer and sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators. The results of the tests allowed us to conclude that a hybrid structure with a polyacrylate scaffolding and a silicate matrix had been obtained. The results of the rheological analysis revealed that the hydrogel sample with a 1:7 mass ratio of sodium water glass to the sodium polyacrylate is characterized by the highest complex viscosity. Thermal analysis (Thermogravimetry/Differential Scanning Calorimetry (TG/DSC)) showed that water begins to evaporate at higher temperatures, from 120 °C to even 180 °C. These results were confirmed by mid-infrared spectroscopy (MIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. Differences in the intensity of the peaks derived from water in the MIR spectra indicate that most of the water is bounded. In turn, NMR results showed that the mobility of water molecules decreases as the amount of sodium water glass in the mixture increases.

Poly (Methacrylic Acid)-Grafted-Okra Gum: Synthesis, Characterization and Evaluation as Mucoadhesive

Recently, worldwide extensive attention is being paid in exploration and exploitation of pharmaceutical excipients from natural resource. Various natural polysaccharides have been significantly reported as prospective drug delivery carriers. These natural gums are preferred over synthetic polymers because of their biocompatibility, low cost, free availability and biodegradability. But due to variable chemical composition, microbial load, microbial growth and hange in viscosity upon aging, acceptability is low compared to commercial synthetic products. Tailoring or modification may be an approach to make them smart as drug carriers specially in order to modulate the site of drug release and it’s kinetic. The chemical modification of okra gum (OG) was the main objective of the present study in order to make it potential mucoadhesive for the application in mucoadhesive drug delivery. In this study, methacrylic acid was grafted onto okra gum. At first, okra gum has been isolated from the fruits of Hibiscus esculentus. Poly (methacrylic acid)-grafted-okra gum (PMAc-g-OG) was synthesized employing a microwave- promoted and redox-initiated method. Potassium persulphate was used as free- radical-initiator. Methacrylic acid was mixed to 1% solution of OG and then 30 ml of potassium per sulphate aqueous solution was added to the previous mixture along with continuous stirring. The mixture was exposed to microwave in a domestic micro-oven. The mixture was kept overnight and the copolymer was collected and purified using acetone and aqueous methanol (30% v/v) subsequently. The copolymer was characterized by elemental analysis, FTIR, DSC-TGA, and 13C NMR study. Ex-vivo mucoadhesion test was performed using goat stomach. A highest % grafting of 448.32% was found in the synthetic procedure employed in the study. The characterization studies also substantiate the successful grafting. Ex-vivo mucoadhesion study also showed excellent mucoadhesive capacity over a period of 16 hours. The study exhibited that the method employed was very simple, less time consuming, one-pot and without N2 atmosphere. The copolymer also exhibited excellent mucoadhesivity which might be applied in different mucoadhesive drug delivery systems such as prolonged release gastroretentives, buccal gels, etc.

Metal-free, room temperature, acid-K2S2O8 mediated method for the nitration of olefins: an easy approach for the synthesis of nitroolefins

Here, we have developed a simple, room temperature method for the nitration of olefins by using inexpensive sodium nitrite as a source of nitro groups in the presence of TFA and potassium persulphate under an open atmosphere.