Synthesis,Characterization and Environmental Applications of a New Bio-Composite Gelatin-Zr(IV) Phosphate

Gelatin-Zr(IV) phosphate composite (GT/ZPC) was synthesized by sol–gel method. Different techniques viz. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray powdered diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used for the characterisation of GT/ZPC composite ion exchanger. The ion exchange capacity (IEC) of GT/ZPC was observed to be better (1.04 meq g^?1) than its inorganic counterpart (0.64 meq g^?1). The pH studies revealed the monofunctional nature of GT/ZPC with one inflection point. The distribution studies showed that the GT/ZPC was highly selective for Cd²⁺ as compare to other metal ions. The environmental applicability of ion exchanger has been analysed for binary separations of metal ions using column method. Cd²⁺ was effectively removed from synthetic mixture of metal ions (Zn²⁺, Pb²⁺, Ni²⁺, Co²⁺ and Cu²⁺).     

Application of ameliorated wood pulp to recover Cd(II), Pb(II), and Ni(II) from e-waste

In this study, dl-malic acid and hydrogen peroxide were used as leaching agents to remove metals from e-waste (printed-circuit boards) and itaconic acid-grafted poly(vinyl alcohol)-encapsulated wood pulp (IA-g-PVA-en-WP) to uptake metals from leachate with high proficiency [11.63 mg g^?1; 93.03 % for Cd(II), 11.90 mg g^?1; 95.18 % for Pb(II), and 12.14 mg g^?1; 97.08 % for Ni(II)]. Metals were recovered from the loaded biosorbent by desorption studies. The standard analytical techniques, such as elemental analysis, Fourier-transform-infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and thermogravimetric analysis, were used to characterize the recovering agent (biosorbent). At equilibrium, the metal uptake data were fitted to Langmuir and D–R isotherms (R ² > 0.99) significantly, revealing, the homogeneous distribution of active sites on biosorbent’s backbone. The possible mechanism appeared to be ion exchanges of metal ions with H⁺ together with binding over functionalities (COO^?). Dimensionless equilibrium parameter (R _L) showed the favourability of metal uptake at lower concentration, while mean adsorption energy (E) certified the physical binding of metal on functionalities which was further confirmed by sticking probability and activation energy parameters. Reusability studies were also conducted to state the performance of biosorbent.     

Green Synthesis and Antioxidant Study of Silver Nanoparticles of Root Extract of <Emphasis Type="Italic">Sageretia thea</Emphasis> and Its Role in Oxidation Protection Technology

Development of environmentally friendly synthesis of nanoparticles is one of the important areas of research in nanotechnology. In present study silver naopartticles (AgNPs) of root extract of Sageretia thea (S. thea) were synthesized at room temperature. The synthesized AgNPs were characterized by UV. Visible spectroscopy (UV), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDX), transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier transform infrared (FT-IR) spectroscopy. Formation of AgNPs was confirmed by visual examination the colour change from yellow to brick red due to surface Plasmon resonance band at 435 nm. SEM and TEM analysis of synthesized AgNPs revealed spherical morphology with average particle size 25 nm. Crystalline nature of the AgNPs in face centered cubic structure is evident from the selected area electron diffraction (SAED) and XRD pattern. The presence of elemental Ag was confirmed by EDX analysis at 3kv. Different functional groups which responsible for reduction and stabilization of reaction medium was confirmed by FTIR spectroscopy. The biosynthesized AgNPs showed strong DPPH and dye protection radical scavenging assay while modest hydrogen peroxide radical scavenging assay as compare to crude extract. The present investigations suggest that biosynthesized nanoparticles have a high potential for use in the preparation of drugs used against various diseases and also a promising candidate for many medical applications.     

Tailor Made Thin Film Composite Membranes: Potentiality Towards Removal of Hydroquinone from Water

The study investigated the use of thin film composite membrane (TFC) as a potential candidate for hydroquinone removal from water. Thin film composite membranes were prepared by polyamide coating on Polysulfone asymmetric membrane. FTIR study was performed to verify the Polysulfone as well as polyamide functionality. TFC membrane was characterized by contact angle, zeta potential, scanning electron microscopy studies. The salt rejection trend was seen from 500 to 1000 mg/L. The membrane is marked by permeability co-efficient B based on solution diffusion studies. The value is 0.98 × 10^?6 m/s for NaCl solution at 1.4 MPa. The separation performance was 88.87% for 5 mg/L hydroquinone at 1.4 MPa. The separation was little bit lowered in acid medium because of the nature of the membrane and feed solute chemistry. The ‘pore swelling’ and ‘salting out’ influenced hydroquinone separation in the presence of NaCl. The hydroquinone separation was 80.63% in 1000 mg/L NaCl solution. In acidic pH, NaCl separation was influenced much more compared to hydroquinone. The separation is influenced by field water matrix.     

Sulfated Polysaccharides from Tunisian Fish Skins: Antioxidant,DNA Damage Protective Effect and Antihypertensive Activities

Sulfated polysaccharides were isolated from two Tunisian fish skins grey triggerfish (Balistes capriscus) (GTSP) and smooth hound (Mustelus mustelus) (SHSP). Their chemical and physical characteristics were investigated. The Analysis of surface morphology by scanning electron microscopy of both sulfated polysaccharides displayed the same shape with netted structure. The antioxidant activities of GTSP and SHSP were evaluated using various in vitro antioxidant assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, reducing power, β-carotene bleaching inhibition assay (IC_{50 GTSP} = 0.5 mg mL^?1 and IC_{50 SHSP} = 0.6 mg mL^?1) and DNA nicking assay. Both sulfated polysaccharides exhibited good antioxidant activities. The sulfated polysaccharides showed strong angiotensin I-converting enzyme inhibitory activities (IC_{50 GTSP} = 0.16 mg mL^?1 and IC_{50 SHSP} = 0.18 mg mL^?1). These results revealed that GTSP and SHSP exhibited significant antihypertensive activities. Overall, the results indicated that grey triggerfish and smooth hound skins can be used to generate high value-added products, thus offering a valuable source of bioactive sulfated polysaccharides for application in wide range of biotechnological applications.     

Fabrication of Biodegradable Superabsorbent Using RSM Design for Controlled Release of KNO<Subscript>3</Subscript>

Present study envisaged the sequential experimental design approach for the development of biodegradable Gelatin-Tapoica/polyacrylamide superabsorbent. Percentage water uptake efficacy of candidate sample was optimized using Response Surface Methodology (RSM) design under microwave irradiation. Different process variables such as potassium persulphate and ammonium persulphate (KPS:APS) ratio, pH, reaction time concentration of acrylamide and N,N-methylene-bis-acrylamide (MBA) were investigated as a function of percentage swelling using sequential experimental design. Maximum liquid efficacy of 1550% was obtained at KPS:APS?=?1.0:0.5; acrylamide?=?7.67?×?10^?1 mol L^?1; MBA?=?1.76?×?10^?2 mol L^?1; pH 10 and time?=?110 s. The 3D crosslinked network formed was characterized using Fourier Transformation Infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopic (SEM) techniques and thermal stability was ensured by Thermal gravimetric Analysis/Differential Thermal Analysis/Differential Thermal Gravimetric (TGA/DTA/DTG) studies. Superabsorbent synthesized could increase the moisture content in different type of soils and was found to enhance the water-holding capability of the soil upto 60 days in clayey, 40 days in sandy and 51 days in mixture of two soils under controlled conditions. Further, candidate polymer was investigated for the in-vitro controlled release of the KNO₃ with diffusion exponent ‘n’ was found to be 0.4326 indicating Fickian type diffusion. Also, initial diffusion coefficient (D_I?=?3.49?×?10^?5 m² h^?1) was found to be greater than the lateral diffusion coefficient (D_L?=?3.76?×?10^?6 m² h^?1) indicated rapid release of KNO₃ during initial hours with slow release afterwards. The ecofriendly nature of the synthesized polymer was also tested by conducting biodegradation studies and it was found to degrade upto 94% and 88.1% within 70 days with degradation rate of 1.34 and 1.26% per day using composting method and vermicomposting method respectively. So, the synthesized candidate polymer was found to be boon for agriculture-horticulture sector with wide applicability.     

Optimal Design of Ozone Bleaching Parameters to Approach Cellulose Nanofibers Extraction from Sugarcane Bagasse Fibers

Cellulose nanofibers (CNFs) were isolated from sugarcane bagasse (SCB) through the combination of bio-refinery, sulfur-free, and totally chlorine free (TCF) chemo-mechanical pretreatments, with a focus on the optimal design of ozone bleaching parameters based on a response surface methodology (RSM). For this purpose, the most effective parameters in ozone bleaching (temperature, time, and pulp consistency) were set between 40 and 85 °C, 60 and 360 min, and 1–5 wt%, respectively. High-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), Kappa number, and scanning electron microscopy (SEM) were used to chemically and morphologically characterize the SCB fibers. The size distribution and morphology of CNFs were also evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). HPLC analysis revealed that percentage of cellulose increased from 41.5 to 91.39% after chemical pretreatments. FTIR and Kappa number analyses also confirmed the successful isolation of cellulose fibers from the SCB fibers after chemical pretreatments. Furthermore, DLS results showed that the hydrodynamic diameter of the isolated cellulose fibers reduced to 268 nm by dint of ultrasonication. Additionally, TEM images confirmed the isolation of CNFs: the average diameter of cellulose fibers decreased to about 28 nm after mechanical steps and the yield of fibrillation was found to be around 99%. According to the obtained results, the applied chemo-mechanical treatment appears to be promising for green and facile isolation of CNFs.     

Cost Effective Production of Poly-β-Hydroxybutyrate by Bacillus subtilis NG05 Using Sugar Industry Waste Water

The present study describes the treatment of sugar industry waste water and its use as a potential low cost substrate for production of bioplastic by Bacillus subtilis NG05. The B. subtilis NG05 grow at the rate of 0.14 g h^?1 L^?1 of production media used and accumulate the 50.1 % of poly β-hydroxybutyrate (PHB). The phase contrast microscopy revealed the presence of PHB granules in B. subtilis NG05 which was further confirmed by Fourier transform infrared spectroscopy and ¹H-nuclear magnetic resonance. The polymer was further analysed by differential scanning calorimetry. PHB production yield was achieved up to 4.991 g L^?1 with Sugar industry waste water as sole nutrient source. Thus the process provided dual benefits of conversion of a waste material into value added product, PHB and waste management.     

Extraction and Characterization of Nanocrystalline Cellulose from Doum (<Emphasis Type="Italic">Chamaerops humilis</Emphasis>) Leaves: A Potential Reinforcing Biomaterial

The aim of this investigation was to extract nanocrystalline cellulose (NCC) from Moroccan Doum fibers (Chamaerops humilis) by chemical treatment to examine their potential for use as reinforcement fibers in bionanocomposite applications. The chemical composition, morphological and structural properties of the Doum fibers was determined at different stages of chemical treatment. Morphological (transmission electron microscopy and scanning electron microscopy), structural characterization (X-ray diffraction, Fourier transformed infrared), thermal characterization (thermogravimetric analysis). The suspension electrostatic stabilization (zeta potential) of NCCs was also carried out. The results of these characterization analysis found that average size of the NCC is 220 nm in length and 11 nm in diameter, with high crystallinity index (93 %), a thermal stability comparable to that of untreated Doum fibers (degradation temperature 340 °C), which is reasonably promising for the use of these nanofibers in reinforced-polymer manufacturing, and a good stability in water suspension that it allows their utilization such as reinforcement of the water-soluble polymers to prepare the bio-nanocomposite.     

Characterization of residue from leached cathode ray tube funnel glass: reutilization as white carbon black

Cathode ray tube (CRT) funnel glass remains an urgent environmental problem and is composed mainly of lead oxide and silicon oxide. In this research, the residue could be obtained from 2 h to 500 rpm activated CRT funnel glass after extracting lead via acid leaching under the conditions of HNO₃ concentration 1.0 mol/L, leaching temperature 95 °C and leaching time 1 h. In order to reutilize the residue, its physico-chemical properties were characterized by scanning electron microscopy, Brunauer–Emmett–Teller, thermogravimetric analysis, X-ray diffraction and Fourier transform infrared spectroscopy. The results indicated that the residue was an amorphous superfine powder with approximately 93 wt% silica oxide and specific surface area of more than 170 m²/g. It can be reutilized as white carbon black.     

Adsorption of Ammonium by Graphene Oxide-Based Composites Prepared by UV Irradiation and Using as Slow-Release Fertilizer

A novel sodium alginate-grafted poly(acrylic acid)/graphene oxide (NaAlg-g-PAA/GO) composite hydrogel was prepared via ultraviolet irradiation, and characterized by infrared spectroscopy spectrometer. X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. It was employed to adsorb NH₄⁺ from aqueous solution and used as slow-release nitrogen fertilizers (SNFs). Result indicated that the adsorption process for NH₄⁺ reached equilibrium within 50 min, with the adsorption capacity of 6.6 mmol g^?1 even if 30 wt% GO was incorporated. The results of adsorption kinetic and isotherm were well described by the pseudo-second-order and Freundlich model. The thermodynamics analysis showed the adsorption process was spontaneous. The study indicated excellent water-holding ratio of soil with 2 wt% SNFs was 81.2%, and nitrogen release was up to 55.1% within 40 days in soil. Overall, NaAlg-g-PAA/GO could be considered as an efficient adsorbent for the recovery of nitrogen with the agronomic reuse as a fertilizer.     

Degradation Study of Biobased Polyester–Polyurethane and its Nanocomposite Under Natural Soil Burial,UV Radiation and Hydrolytic-Salt Water Circumstances

The current study focuses on the development of a formulation of polyester polyurethane (PEPU) samples using castor oil (CO) modified polyester polyol and partially biobased aliphatic isocyanate. The CO modified polyester polyol was synthesized employing transesterification reaction between CO and diethylene glycol in the presence litharge (PbO) catalyst. Subsequently, the modification of CO was confirmed using proton nuclear magnetic resonance (¹HNMR) spectra analysis. In the next stage, the biobased polyester polyurethane nanocomposites (PEPUNC) were prepared by incorporating 3 wt% OMMT nanoclay within PEPU through in situ polymerization technique. The produced PEPU was confirmed by Fourier transform infrared spectroscopy (FTIR) and ¹HNMR spectra analysis. Further, the degradation properties of developed PEPU subjected to soil-burial, UV exposure and hydrolytic-salt water medium were noted by FTIR spectroscopy. Corresponding weight loss, mechanical measurements and morphological studies through scanning electron microscopy (SEM) analysis were studied. The results showed that the addition of OMMT nanoclay within the PEPU matrix produces significant improvement in the degradation rate which indicated the susceptibility of OMMT nanoclay to humidity upon exposure to soil burial. The produced microorganisms from the soil resulted in significant chemical and morphological changes in the entire structure of the PEPU. Additionally, the highest degradation and percentage of weight loss was observed under soil burial as compared to UV exposure and hydrolytic-salt water medium.     

Effect of Hexadecyl Lactate as Plasticizer on the Properties of Poly(<Emphasis Type="SmallCaps">l</Emphasis>-lactide) Films for Food Packaging Applications

In this study, poly(l-lactide) (PLA) films were fabricated by melt processing and the plasticizing effect of hexadecyl lactate (HL) (0, 5, 7.5, 10, and 12.5 wt% on PLA were investigated by scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, tensile, transparency, and water vapor permeability tests. The SEM analysis revealed that PLA with 10 wt% HL appeared uniform with extra small bumps, confirmed the interaction between PLA and HL. The thermal analysis revealed a glass transition temperature of 57.4 °C for neat PLA film, but the addition of HL elicited a decrease in the temperature of the peak (43.8 °C). The incorporation of plasticizer into PLA resulted in the increase of elongation at break, as well as the decrease of tensile strength and tensile modulus. Even though a decrease in transparency was recorded, the PLA/HL blend films appeared transparent by visually observation. The water vapor permeability of PLA/HL blend films increased with the increase of HL. The PLA/HL blend films could effectively extend the shelf-life of fresh-cut pears as the commercial low density polyethylene films. The results indicated that the properties of PLA films can be modified with the addition of HL and PLA/HL blend films could serve as an alternative as food packaging materials to reduce environmental problems associated with synthetic packaging films.     

Adsorption Kinetics of Dyes in Single and Binary Systems Using Cyanoguanidine-Crosslinked Chitosan of Different Deacetylation Degrees

The crosslinking of chitosan with cyanoguanidine shows some advantages, such as the improved the stability in acid solutions and the decrease of adsorbent cost. In this work, cyanoguanidine-crosslinked chitosan and pure chitosan were prepared to apply in the adsorption of Food Yellow 4 (FY4) and Food Blue 2 (FB2), in single and binary systems. Effects of pH and deacetylation degree (DD) of chitosan in adsorption were evaluated. The adsorbents were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The kinetic data were analyzed by pseudo-first order, pseudo-second order and Avrami models. The conditions of pH 3 and DD 95% were the more suitable to reach the highest adsorption capacities in all experimental assays. Under these conditions, the adsorption capacities for FY4 were approximately of 392 and 200 mg g^?1 and, for FB2 were approximately of 370 and 184 mg g^?1, respectively, in the single and binary systems. The Avrami model was suitable to represent the kinetic curves in all conditions, and the highest adsorption capacities were found for FY4 in binary aqueous system, being for the pure chitosan of 229 mg g^?1 and crosslinked chitosan of 218 mg g^?1. The Langmuir and extended Langmuir models presented a good fit to the equilibrium data in both systems. It was found that, the chitosan crosslinked with cyanoguanidine improved the chemical stability of chitosan as adsorbent.     

Preparation,Characterization, and Rapid Adsorption of Hg<Superscript>2+</Superscript> on Nanoscale Aramid-based Adsorbent

A series of nanaoscale aramid-based adsorbents were prepared by the functionalization of poly (p-phenylene terephthalamide) (PPTA) with different content of ethylenediamine (EDA). Their structures were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and elemental analysis. Metal ions, including Hg²⁺, Pb²⁺, Ag⁺, Cu²⁺, Cd²⁺, and Ni²⁺ were chosen as the models to explore the binding behaviors of PPTA–ECH–EDA in aqueous medium. Results showed that PPTA–ECH–EDA exhibited higher adsorption capacity for Hg²⁺ due to their nanoscale structures. In particular, the adsorption rate was so high that equilibrium was achieved within 15 min for Hg²⁺. The adsorption of Hg²⁺ on PPTA–ECH–EDA followed the pseudo second-order model well. Langmuir and Freundlich models were employed to fit the isothermal adsorption, and the results revealed that Freundlich isotherm was a better model to predict the experimental data. The adsorption mechanism was revealed by X-ray photoelectron spectroscopy. It is preconceived that PPTA–ECH–EDA could be used as an effective adsorbent for fast removal of heavy ions from wastewater.     

The Influence of Artificial Photodegradation on Properties of Poly(3-hydroxybutyrate-<Emphasis Type="Italic">co</Emphasis>-3-hydroxyvalerate)(PHBV)/Graphite Nanosheets (GNS) Nanocomposites

The potential use of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/graphite nanosheets (GNS) as a biodegradable nanocomposite has been explored. PHBV/GNS nanocomposites films were prepared by solution casting at various concentrations of GNS—0.25, 0.50 and 1.00 wt% GNS. The films were exposed to artificial ultraviolet radiation (UV) during 52 h. The effect of GNS on PHBV photodegradation was investigated and compared to neat PHBV film. The artificial photodegradation induced changes in physical (weight loss), chemical carbonyl index by Fourier transform infrared spectroscopy, thermal degree of crystallinity and melting temperature by differential scanning calorimetry and morphological scanning electron microscopy characteristics. Based on the results obtained from aforementioned analyzes it was verified that GNS inhibits the oxidative degradation of PHBV matrix.     

Thermal,Rheological, Mechanical and Morphological Behavior of High Density Polyethylene and Carboxymethyl Cellulose Blend

In this study water soluble sodium carboxymethyl cellulose (CMC) was blended with high density polyethylene (HDPE) by peroxide-initiated melt compounding technique. The compatibility of the blended polymers were carried out by silane crosslinking agent. A series of blends were prepared by varying the CMC contents up to a maximum of 50 phr. The physical properties of non-crosslinked and crosslinked blends were investigated in detail. FTIR analysis of crosslinked blend confirmed the presence of Si–O–Si and Si–O–C absorption peaks at 1050 and 1159 cm^?1. Thermal stability of crosslinked blends improved as compared to its non-crosslinked congener. Rheological study of crosslinked blends illustrated high complex viscosity and dynamic shear storage modulus. The tensile strength of virgin polyethylene was 8.1 MPa whereas the maximum tensile strength of 19.6 MPa was observed in crosslinked blend. Similarly lower deformation was observed in crosslinked blends under static load. Scanning electron microscopy of crosslinked formulations also showed strong adhesion between the polymers interface. The compatibility of HDPE and CMC is attributed to both free radical and condensation reactions.     

Degradation of a Terephthalate-containing Polyester by Thermophilic Actinomycetes and <Emphasis Type="Italic">Bacillus</Emphasis> Species Derived from Composts

We intended to find thermophilic degraders of terephthalate-containing Biomax^® films. Films in mesh bags were buried in composts (inside temperature: approximately 55–60 °C), resulting in the degradation of them in 2 weeks. Fluorescent microscopy of films recovered from composts showed that microorganisms gradually covered the surface of a film during composting. DGGE analysis of microorganisms on the composted film indicated the presence of Bacillus species as main species (approximately 80% of microbial flora) and actinomycetes (approximately 10–20%) as the second major flora. Isolation of Biomax^®-utilizing bacteria was focused on these two genera: two actinomycetes and one Bacillus species were isolated as pure best degraders from the composted polymer films, which were fragmented into small pieces. All the strains were thermophilic and identified, based on their 16S rDNA analyses. Degradation of polymer films was confirmed by (1) accelerated fragmentation of films in composts, compared with a control (no inoculum) and resultant decrease in molecular weights, (2) growth in a powdered Biomax^® medium, compared with a control without powdered Biomax^®, and (3) production of terephthalate in a powdered Biomax^® medium. In this way, we concluded that these bacteria were useful for degradation of thermostable Biomax^® products.     

Adsorptive Removal of Malachite Green Chloride and Reactive Red-198 from Aqueous Solutions by Using Multiwall Carbon Nanotubes-Graft-Poly (2-acrylamido-2-methyl-1-propanesulfonic acid)

The multiwall carbon nanotubes (MWCNTs) were modified by 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) via grafting reaction and γ-rays of ⁶⁰Co source was used as initiator. The outcome product was called hydroxyethylated (HOEt-MWCNTs) graft poly(AMPS) and abbreviated as HOEt-MWCNTs-g-PAMPS. The parameters that affected the grafting yield were optimized. The maximum grafting obtained was ~20 %. HOEt-MWCNTs-g-PAMPS were characterized by Fourier transform infra red, scanning electron microscopy, high resolution transmission electron microscopy, thermal gravimetric analysis. The adsorptive removals of malachite green chloride (MGC) and reactive red 198 (RR-198) onto HOEt-MWCNTs-g-PAMPS were studied at variable conditions. The adsorption isotherms were analyzed using Langmuir, Redlich–Peterson, Freundlich, Khan and Sips models. The results referred that Sips model is the best fitting to adsorption of MGC and Freundlich model is the best fitting to RR-198 adsorption. The monolayer coverage capacities of HOEt-MWCNTs-g-PAMPS for MGC and RR-198 dyes were found 172 and 323 mg g^?1, respectively. The rate of kinetic adsorption processes of MGC and RR-198 onto HOEt-MWCNTs-g-PAMPS were described by using pseudo-first order, pseudo-second order and intraparticle diffusion models. The pseudo-first order and pseudo-second order models were the best choice among the kinetic models to depict the adsorption behaviors of MGC and RR-198 dyes onto HOEt-MWCNTs-g-PAMPS, respectively. Further, the effect of temperature on the adsorption isotherms was investigated and the thermodynamic parameters were obtained. The results indicated that the adsorption process is spontaneous and endothermic. The values of ΔG° varied in range with the mean values showing a gradual increase from ?3.17 to ?3.64 kJ mol^?1 for MGC and ?3.36 to ?3.73 kJ mol^?1 for RR-198. The reusability and regeneration of adsorbent were investigated. The outcome data referred to that the efficiency of adsorbent >98 %. The outline results declared that there is a good potentiality for the HOEt-MWCNTs-g-PAMPS to be used as an adsorbent for the removal of MGC and RR-198 from aqueous solutions.     

Biodegradable Chitosan-g-Poly(methacrylamide) Microspheres for Controlled Release of Hypertensive Drug

Chitosan-g-poly(methacrylamide) (CS-g-PMAAm) was synthesized by redox polymerization. The synthesized graft copolymers were used to prepare microspheres (MS) by water/oil (W/O) emulsion technique and cross-linked with glutaraldehyde (GA). Developed microspheres were encapsulated using enalapril maleate (ENAM) as a model drug (hypertension) and characterized by fourier transform infrared spectroscopy, differential scanning calorimetry and scanning electron microscopy. The physico-chemical properties of the microspheres were studied by calculating drug entrapment efficiency, and drug release kinetics. % of encapsulation efficiency (% EE) increased with increase in drug loading and methacrylamide (MAAm) content. The minimum % EE (65.2 ± 1.6) was observed in case of microsphere containing 40 % MAAm, 5 % ENAM and 10 mL glutaraldehyde. The release profiles indicate that formulation containing highest (10 mL) crosslinking agent microspheres has the slow release.