Non-lamellar lyotropic liquid crystalline nanoparticles as nanocarriers for enhanced drug encapsulation of atorvastatin calcium and proanthocyanidins

Atorvastatin calcium (ATV) and proanthocyanidins (PAC) have a strong antioxidant activity, that can benefit to reduce the atherosclerotic plaque progression. Unfortunately, the bioavailability of ATV is greatly reduced due to its limited drug solubility while the PAC drug is unstable upon exposure to the atmospheric oxygen. Herein, the lyotropic liquid crystalline nanoparticles (LLCNPs) constructed by a binary mixture of soy phosphatidylcholine (SPC) and citric acid ester of monoglyceride (citrem) at different weight ratios were used to encapsulate the hydrophobic ATV and hydrophilic PAC. The LLCNPs were further characterized by small-angle X-ray scattering and dynamic light scattering. Depending on the lipid composition, the systems have a size range of 140-190 nm and were able to encapsulate both drugs in the range of 90-100%. Upon increasing the citrem content of drug-loaded LLCNPs, the hexosomes (H2) was completely transformed to an emulsified inverse micellar (L2). The optimum encapsulation efficiency (EE) of ATV and PAC were obtained in citrem/SPC weight ratio 4:1 (L2) and 1:1 (H2), respectively. There was a substantial change in the mean size and PDI of the nanoparticles upon 30 days of storage with the ATV-loaded LLCNPs exhibiting greater colloidal instability than PAC-loaded LLCNPs. The biphasic released pattern (burst released at the initial stage followed by the sustained released at the later stage) was perceived in ATV formulation, while the burst drug released pattern was observed in PAC formulations that could be attributed by its internal H2 structure. Interestingly, the cytokine studies showed that the PAC-LLCNPs promisingly up regulate the expressions of tumor necrosis factor-alpha (TNF-α) better than the drug-free and ATV-loaded LLCNPs samples. The structural tunability of citrem/SPC nanoparticles and their effect on physicochemical characteristic, biological activities and potential as an alternative drug delivery platform in the treatment of atherosclerosis are discussed.

Increased radical scavenging activity of thymoquinone and l-ascorbic acid dual encapsulated in palmitoyl-chitosan nanoparticles in a human normal lung fibroblast, MRC-5 due to synergistic antioxidative effects

Less effective antioxidant supplementation in combating free radicals is often related to the lack of the formulation of carriers. The antioxidant may be one of the most powerful substances but is marred by poor uptake by cells when the carrier degraded and dissolved too rapidly. Nanoparticle (NP) systems are promising in overcoming the problem since they provide high surface area to enhance encapsulation and release efficiency. With the right selection of material, NP carriers could function as constructive antioxidant cargos. Generally, NPs carry only one active ingredient; this study, however, utilized chitosan nanoparticles (CNPs) and hydrophobically modified palmitoyl-chitosan nanoparticles (PCNPs) that were dual encapsulated with antioxidants of different polarities, namely, hydrophobic thymoquinone (TQ) and hydrophilic l-ascorbic acid (LAA) to evaluate their combination effects in scavenging free radicals. The antioxidants followed zero-order release kinetics with a controlled release manner for about 48 h. The interaction effects between TQ and LAA loaded in the NP systems were determined by classical isobologram (CI) values. The CI values were derived by a diphenyl picrylhydrazyl (DPPH) assay, a radical scavenging activity assay. Combined TQ and LAA had CI values of less than one, with a lower value in the PCNP system than in the CNP system. This indicates that the interaction between those antioxidants showed higher synergistic effects in PCNPs, which enhanced the DPPH radical scavenging activities. The antioxidative potential of compound(s) encapsulated in the PCNP carrier was further experimented by a reactive oxygen species (ROS) assay on a human normal lung fibroblast cell line (MRC-5) as lung is one of the organs with high accumulation of free radicals. About 48 h post treatment, the dual-loaded TQ and LAA in PCNPs showed the lowest ROS level in comparison to single-loaded antioxidants and bare antioxidant delivery. The hydrogen peroxide (H2O2) radical scavenging was influenced by both the controlled release property of the PCNP system and the synergy between TQ and LAA. In short, dual-loaded TQ and LAA in the hydrophobically modified PCNP had effectively depicted the capability of a single CS-based nanocarrier to hold more than one compound at a time to function as a potent radical scavenger.

Synthesis of Calcium Peroxide Nanoparticles with Starch as a Stabilizer for the Degradation of Organic Dye in an Aqueous Solution

One of the most significant environmental problems in the world is the massive release of dye wastewater from the dyeing industry. Therefore, the treatment of dyes effluents has received significant attention from researchers in recent years. Calcium peroxide (CP) from the group of alkaline earth metal peroxides acts as an oxidizing agent for the degradation of organic dyes in water. It is known that the commercially available CP has a relatively large particle size, which makes the reaction rate for pollution degradation relatively slow. Therefore, in this study, starch, a non-toxic, biodegradable and biocompatible biopolymer, was used as a stabilizer for synthesizing calcium peroxide nanoparticles (Starch@CPnps). The Starch@CPnps were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), dynamic light scattering (DLS), thermogravimetric analysis (TGA), energy dispersive X-ray analysis (EDX) and scanning electron microscopy (SEM). The degradation of organic dyes, methylene blue (MB), using Starch@CPnps as a novel oxidant was studied using three different parameters: initial pH of the MB solution, calcium peroxide initial dosage and contact time. The degradation of the MB dye was carried out via a Fenton reaction, and the degradation efficiency of Starch@CPnps was successfully achieved up to 99%. This study shows that the potential application of starch as a stabilizer can reduce the size of the nanoparticles as it prevents the agglomeration of the nanoparticles during synthesis.

Removal of Cationic Dyes by Iron Modified Silica/Polyurethane Composite: Kinetic, Isotherm and Thermodynamic Analyses, and Regeneration via Advanced Oxidation Process

Emerging dye pollution from textile industrial effluents is becoming more challenging for researchers worldwide. The contamination of water by dye effluents affects the living organisms in an ecosystem. Methylene blue (MB) and malachite green (MG) are soluble dyes with a high colour intensity even at low concentration and are hazardous to living organisms. The adsorption method is used in most wastewater plants for the removal of organic pollutants as it is cost-effective, has a high adsorption capacity, and good mechanical stabilities. In this study, a composite adsorbent was prepared by impregnating iron modified silica (FMS) onto polyurethane (PU) foam to produce an iron modified silica/polyurethane (FMS/PU) composite. The composite adsorbent was utilised in batch adsorption of the cationic dyes MB and MG. The effect of adsorption parameters such as the adsorbent load, pH, initial dye concentration, and contact time were discussed. Adsorption kinetics and isotherm were implemented to understand the adsorption mechanism for both dyes. It was found that the adsorption of MB and MG followed the pseudo-second order model. The Langmuir model showed a better fit than the Freundlich model for the adsorption of MB and MG, indicating that the adsorption occurred via the monolayer adsorption system. The maximum adsorption capacity of the FMS/PU obtained for MB was 31.7 mg/g, while for MG, it was 34.3 mg/g. The thermodynamic study revealed that the adsorption of MB and MG were exothermic and spontaneous at room temperature. In addition, the regeneration of FMS/PU was conducted to investigate the composite efficiency in adsorbing dyes for several cycles. The results showed that the FMS/PU composite could be regenerated up to four times when the regeneration efficiency dropped drastically to less than 20.0%. The impregnation of FMS onto PU foam also minimised the adsorbent loss into the environment.

The influence of ionic liquid pretreatment on the physicomechanical properties of polymer biocomposites: A mini-review

Increasing concern for the environment has led researchers to pay more attention to the fabrication of polymer biocomposites for many different applications. Polymer biocomposites have generally been fabricated utilizing synthetic or natural polymers with natural fillers. Recently, ionic liquids have been used for the pretreatment of natural fillers prior to the fabrication of polymer biocomposites. In this mini-review, four types of ionic liquids used for the pretreatment of natural filler are classified, specifically chloride-, diethyl phosphate-, acetate-, and bistriflimide-based ionic liquids. In addition, the pretreatment processes of natural fillers with ionic liquids are described in this review. Furthermore, the influence of ionic liquid pretreatment on the physicomechanical properties of polymer biocomposites is succinctly reviewed. Besides, the information presented in this review contributes to a clearer understanding of the process of ionic liquid pretreatment and the vital physicomechanical properties of polymer biocomposites. In summary, most ionic liquid pretreatments can improve almost all physicomechanical properties of polymer biocomposites.

Synthesis of Controlled-Release Calcium Peroxide Nanoparticles Coated with Dextran for Removal of Doxycycline from Aqueous System

Nanoscale calcium peroxide (nCP) has turned out to be one of the effective and environmentally friendly approaches for wastewater remediation purposes. The rapid hydrolysis of nCPs and burst oxygen release caused by the high surface-to-volume ratio of nCPs could surpass the appropriate demand for oxygenation and pollutant degradation in the aqueous system. Thus, coated oxidants (COs) have been prepared using polymeric materials to ensure long-term efficacy and slow-release capability. Therefore, the nCPs were first prepared using dextran as a stabilizer to prevent irreversible agglomeration by the chemical precipitation method and had an average mean size of 2.33 ± 0.81 nm. The synthesized nCPs were then coated with dextran to produce dextran-coated nCPs. Their characteristics and effectiveness in doxycycline (DOX) degradation were assessed. The characterization of nCPs and dextran-coated nCPs was performed using X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared spectroscopy (FTIR), Brunauer, Emmett and Teller analysis (BET), dynamic light scattering (DLS) and thermogravimetric analysis (TGA) techniques. This work suggests that dextran-coated nCPs are beneficial in wastewater treatment practice in terms of the long-term efficacy of DOX degradation potential.

Polybutylene succinate (PBS)/natural fiber green composites: melt blending processes and tensile properties

An increase in the environmental consciousness at present has enhanced the awareness of researchers in utilizing biodegradable materials for the production of environmentally friendly products. Currently, biodegradable polymers, for example, polylactic acid, polybutylene succinate, polycaprolactone, etc., can be utilized as matrices to produce green composites. Meanwhile, natural fibers have been used as fillers for green composites as they are biodegradable and renewable. In this brief review, the physicochemical properties of selected biodegradable polymer, specifically polybutylene succinate, are demonstrated. Moreover, examples of natural fibers that are usually used to produce green composites are also shown. Additionally, practical methods employed for the preparation of green composites were exposed. The tensile properties of green composites, such as the tensile strength, tensile modulus, and elongation at break at different loadings of natural fibers, are also briefly reviewed. The information obtained in this review provides detailed differences in the preparation methods of green composites. In addition, this brief review supplies a clearer comprehension of the tensile properties of green composites for the usage of semistructural and packaging applications.

Efficient sequestration of boron from liquid phase by amidoxime-functionalized poly(acrylonitrile-co-acrylic acid): experimental and modelling analyses

This study aims to produce amidoxime-modified poly(acrylonitrile-co-acrylic acid) using an optimized method and to investigate the performance of amidoxime-modified poly(acrylonitrile-co-acrylic acid) on the adsorption of boron ions in batch operations. Batch adsorption was conducted at the physiochemical parameters of pH, adsorbent dosage, and initial boron concentration. The isotherms and kinetics of adsorption data were studied at various initial boron concentrations. The renewed synthesis process gave a production yield of 77%, and the conversion of nitrile group to amidoxime was 78%. The adsorption reached its optimum point at pH = 8, adsorbent dosage = 4 g·L^-1, and initial adsorbent concentration at 40 ppm. The best model fits for isotherm adsorption was the Sips model with heterogeneity factor (n) = 0.7611. In the kinetic study, the adsorption data fitted best with pseudo-second-order model. The synthesized polymeric adsorbent could be recycled with little decline in its boron entrapment capacities. Hence, amidoxime-modified poly(acrylonitrile-co-acrylic acid) exhibited high adsorption capacity and could be potentially explored as an alternative to commercial resin in the removal of boron from wastewater.

Properties and applications of cellulose regenerated from cellulose/imidazolium-based ionic liquid/co-solvent solutions: A short review

An improvement of ecological conscience currently has increased the consciousness of researchers in reducing the processing time and cost of solvent for the dissolution of cellulose. Latterly, ionic liquids have been employed to process cellulose as they are recyclable and nonvolatile. Besides that, biopolymers such as chitosan, chitin, starch, protein, and cellulose acetate can also be processed by using ionic liquids for diverse applications. In this short review, examples of imidazolium-based ionic liquids that are commonly used for the dissolution of cellulose are implied. Furthermore, examples of organic liquids that are utilized as co-solvents for ionic liquids were revealed. In addition, examples of imidazolium-based ionic liquid/co-solvent mixtures utilized in the dissolution of cellulose and other biopolymers are also demonstrated. The properties and applications of cellulose and its blends regenerated from different types of cellulose/imidazolium-based ionic liquid/co-solvent solutions are also shortly reviewed. The information acquired from this review gives a better understanding of the changes in the properties of regenerated cellulose and regenerated cellulose blends. In addition, this short review serves as a model basis for the creation of novel applications of regenerated cellulose and regenerated cellulose blends by utilizing imidazolium-based ionic liquid/co-solvent mixtures.

Trimethylamine functionalized radiation-induced grafted polyamide 6 fibers for p-nitrophenol adsorption

The method of pre-irradiation grafting was used with the aid of electron beam (EB) accelerator to accomplish the grafting of polyamide 6 fibers (PA6) with glycidyl methacrylate (GMA). The extent to which GMA was grafted on PA6 was found to be markedly influenced by the absorbed dose of radiation and the reaction time of grafting. Trimethylamine (TMA) was afterwards employed for the functionalization of GMA-grafted fibers (PA6-g-GMA). A range of analyses (e.g., FTIR, FESEM, XRD, BET, and pHpzc) were carried out to determine the physiochemical and morphological properties of the fibrous adsorbent. p-Nitrophenol (PNP) adsorption from aqueous solution was conducted with the resulting TMA-(PA6-g-GMA) adsorbent. The adsorption behaviour of PNP on the fibrous adsorbent was clarified by investigating the adsorption kinetics and isotherm. According to the results, the adsorption of PNP on TMA-(PA6-g-GMA) reflected the pseudo-second order model. Meanwhile, the isotherm analysis revealed that the best description of the equilibrium data was provided by Redlich-Peterson model, followed closely by Langmuir isotherm model. The achieved adsorption capacity was highest at 176.036 mg/g. Moreover, the adsorption was indicated by the thermodynamic analysis to be spontaneous and exothermic. Regeneration and recycling of the adsorbent was possible for a minimum of five cycles with no reduction in adsorption capacity. It was concluded that the fibrous adsorbent could have applications for the removal of PNP at industrial pilot scale.

A Brief Review on the Influence of Ionic Liquids on the Mechanical, Thermal, and Chemical Properties of Biodegradable Polymer Composites

Biodegradable polymers are an exceptional class of polymers that can be decomposed by bacteria. They have received significant interest from researchers in several fields. Besides this, biodegradable polymers can also be incorporated with fillers to fabricate biodegradable polymer composites. Recently, a variety of ionic liquids have also been applied in the fabrication of the polymer composites. In this brief review, two types of fillers that are utilized for the fabrication of biodegradable polymer composites, specifically organic fillers and inorganic fillers, are described. Three types of synthetic biodegradable polymers that are commonly used in biodegradable polymer composites, namely polylactic acid (PLA), polybutylene succinate (PBS), and polycaprolactone (PCL), are reviewed as well. Additionally, the influence of two types of ionic liquid, namely alkylimidazolium- and alkylphosphonium-based ionic liquids, on the mechanical, thermal, and chemical properties of the polymer composites, is also briefly reviewed. This review may be beneficial in providing insights into polymer composite investigators by enhancing the properties of biodegradable polymer composites via the employment of ionic liquids.

Sequestration of p-nitrophenol from liquid phase by poly(acrylonitrile-co-acrylic acid) containing thioamide group

In this paper, the adsorptive performance of synthesized thiourea (TU) modified poly(acrylonitrile-co-acrylic acid) (TU-P(AN-co-AA)) polymeric adsorbent for capturing p-nitrophenol (PNP) from aqueous solution was investigated. TU-P(AN-co-AA) was synthesized via the redox polymerization method with acrylonitrile (AN) and acrylic acid (AA) as the monomers, then modified chemically with thiourea (TU). Characterization analysis with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental microanalysis for CHNS, zeta potential measurement, Brunauer-Emmett-Teller (BET) surface analysis and thermal analyses were carried out to determine the morphology and physico-chemical properties of the synthesized polymer. The characterization results indicated successful surface modification of polymer with TU. The performance of TU-P(AN-co-AA) for the removal of PNP was investigated under various experimental parameters (adsorbent dosage, initial adsorbate concentration, contact time and temperature). The results demonstrated that the Freundlich isotherm model and pseudo-second-order kinetic model best described the equilibrium and kinetic data, respectively. Thermodynamic studies showed that the uptake of PNP by TU-P(AN-co-AA) was spontaneous and exothermic in nature. The results of the regeneration studies suggested that the TU-P(AN-co-AA) polymer is a reusable adsorbent with great potential for removing PNP from wastewater.

Insights into the p-nitrophenol adsorption by amidoxime-modified poly(acrylonitrile-co-acrylic acid): characterization, kinetics, isotherm, thermodynamic, regeneration and mechanism study

This study performs an appraisal of the adsorptive capacity of amidoxime-modified poly(acrylonitrile-co-acrylic acid) or abbreviated as (AO-modified poly(AN-co-AA)) for the p-nitrophenol (PNP) adsorption, from aquatic environments via batch system. The AO-modified poly(AN-co-AA) polymer was developed with redox polymerization, and then altered by using hydroxylamine hydrochloride (HH). Tools used to describe the physicochemical and morphological characteristics of the AO-modified poly(AN-co-AA) were Fourier transform infrared (FTIR) spectroscopy, CHN elemental analysis, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The adsorption kinetics were examined by pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion kinetic models. Meanwhile, the isotherms were investigated by Langmuir, Freundlich, Temkin and Redlich-Peterson models. It was found that the adsorption was best fitted with pseudo-second order, and agreed with both Langmuir and Freundlich isotherm models. It was described best with the Freundlich isotherm due to highest R 2 (0.999). The maximum adsorption capacity was 143.06 mg g-1 at 298 K, and thermodynamic functions showed that the adsorption process was exothermic. Also, following five regeneration cycles, the adsorbent recorded 71.7% regeneration efficiency. The finding in this study indicates that the AO-modified poly(AN-co-AA) is an effective adsorbent to remove PNP from an aqueous solution.

Simultaneous Adsorption of Malachite Green and Methylene Blue Dyes in a Fixed-Bed Column Using Poly(Acrylonitrile-Co-Acrylic Acid) Modified with Thiourea

Proper remediation of aquatic environments contaminated by toxic organic dyes has become a research focus globally for environmental and chemical engineers. This study evaluates the adsorption potential of a polymer-based adsorbent, thiourea-modified poly(acrylonitrile-co-acrylic acid) (T-PAA) adsorbent, for the simultaneous uptake of malachite green (MG) and methylene blue (MB) dye ions from binary system in a continuous flow adsorption column. The influence of inlet dye concentrations, pH, flow rate, and adsorbent bed depth on adsorption process were investigated, and the breakthrough curves obtained experimentally. Results revealed that the sorption capacity of the T-PAA for MG and MB increase at high pH, concentration and bed-depth. Thomas, Bohart-Adams, and Yoon-Nelson models constants were calculated to describe MG and MB adsorption. It was found that the three dynamic models perfectly simulate the adsorption rate and behavior of cationic dyes entrapment. Finally, T-PAA adsorbent demonstrated good cyclic stability. It can be regenerated seven times (or cycles) with no significant loss in adsorption potential. Overall, the excellent sorption capacity and multiple usage make T-PAA polymer an attractive adsorbent materials for treatment of multicomponent dye bearing effluent in a fixed-bed column system.

Preparation of Ethylene Glycol Dimethacrylate (EGDMA)-Based Terpolymer as Potential Sorbents for Pharmaceuticals Adsorption

Ethylene glycol dimethacrylate (EGDMA) is used as a crosslinker in poly(acrylonitrile (AN)-co-vinylbenzyl chloride (VBC)) to investigate the effect of long-chain crosslinker to the porosity of the terpolymer system. Poly(AN-co-EGDMA-co-VBC) is synthesized by using precipitation polymerization method and further hypercrosslinked by Friedel-Crafts reaction. FT-IR spectra of poly(AN-co-EGDMA-co-VBC) show that the absorption bands at ~1290 cm-1 that are assigned to the C-Cl vibrations are almost disappeared in hypercrosslinked (HXL) poly(AN-co-EGDMA-co-VBC) polymers, confirming that the hypercrosslinking reaction is successful. SEM images show that the morphologies of the polymers are retained through the hypercrosslinking reactions. Brunauer-Emmett-Teller (BET) analysis shows that hypercrosslinked polymers had a specific surface area up to 59 m2·g-1. The preliminary performance of the terpolymer adsorbent to capture polar analyte is evaluated by adsorbing salicylic acid and mefenamic acid from aqueous solution in a batch system. The maximum adsorption capacity of salicylic acid and mefenamic acid were up to 416.7 mg·g-1 and 625 mg·g-1, respectively, and the adsorption kinetic data obeyed pseudo-second-order rate equation.

Bio-Based Polymer Electrolytes for Electrochemical Devices: Insight into the Ionic Conductivity Performance

With the continuing efforts to explore alternatives to petrochemical-based polymers and the escalating demand to minimize environmental impact, bio-based polymers have gained a massive amount of attention over the last few decades. The potential uses of these bio-based polymers are varied, from household goods to high end and advanced applications. To some extent, they can solve the depletion and sustainability issues of conventional polymers. As such, this article reviews the trends and developments of bio-based polymers for the preparation of polymer electrolytes that are intended for use in electrochemical device applications. A range of bio-based polymers are presented by focusing on the source, the general method of preparation, and the properties of the polymer electrolyte system, specifically with reference to the ionic conductivity. Some major applications of bio-based polymer electrolytes are discussed. This review examines the past studies and future prospects of these materials in the polymer electrolyte field.

Green Flexible Polyurethane Foam as a Potent Support for Fe-Si Adsorbent

This paper describes the preparation, characterisation, and potential application of flexible palm oil-based polyurethane foam (PUF) as a support for iron-silica (Fe-Si) adsorbent. Fe-Si/polyurethane composite (Fe-Si/PUC) was prepared by impregnating Fe-Si adsorbent onto the surface of PUF by using a novel immersion-drying method. Morphological analysis of Fe-Si/PUC proved that Fe-Si was successfully impregnated onto the surface of PUF. Compression test and thermogravimetric analysis were carried out to determine the flexibility and thermal stability of Fe-Si/PUC, respectively. The Fe-Si/PUC removed 90.0% of 10 ppm methylene blue (MB) from aqueous solution in 60 min. The reusability study showed that Fe-Si/PUC removed 55.9% of MB on the seventh cycle. Hence, the synthesis of Fe-Si/PUC opens up a new path of implementing palm oil-based PUF to assist in the recovery of an adsorbent for environmental clean-up. The mechanism of physical interaction during the impregnation of Fe-Si adsorbent onto PUF was proposed in this paper.

Adsorptive Removal of Methylene Blue from Aquatic Environments Using Thiourea-Modified Poly(Acrylonitrile-co-Acrylic Acid)

The paper evaluates the adsorptive potential of thiourea-modified poly(acrylonitrile-co-acrylic acid), (TA-poly(AN-co-AA)) for the uptake of cationic methylene blue (MB) from aquatic environments via a batch system. TA-poly(AN-co-AA) polymer was synthesized through redox polymerization and modified with thiourea (TA) where thioamide groups were introduced to the surface. Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), CHNS and Zetasizer were used to characterize the physico-chemical and morphological properties of prepared TA-poly(AN-co-AA). Afterwards, it was confirmed that incorporation of thioamide groups was successful. The adsorption kinetics and equilibrium adsorption data were best described, respectively, by a pseudo-second-order model and Freundlich model. Thermodynamic analysis showed the exothermic and spontaneous nature of MB uptake by TA-poly(AN-co-AA). The developed TA-poly(AN-co-AA) polymer demonstrated efficient separation of MB dye from the aqueous solution and maintained maximum adsorption capacity after five regeneration cycles. The findings of this study suggested that synthesized TA-poly(AN-co-AA) can be applied successfully to remove cationic dyes from aquatic environments.

Synthesis and Optimization of Chitosan Nanoparticles Loaded with L-Ascorbic Acid and Thymoquinone

The combination of compounds with different classes (hydrophobic and hydrophilic characters) in single chitosan carrier is a challenge due to the hydrophilicity of chitosan. Utilization of l-ascorbic acid (LAA) and thymoquinone (TQ) compounds as effective antioxidants is marred by poor bioavailability and uptake. Nanoparticles (NPs) solved the problem by functioning as a carrier for them because they have high surface areas for more efficient delivery and uptake by cells. This research, therefore, synthesized chitosan NPs (CNPs) containing LAA and TQ, CNP-LAA-TQ via ionic gelation routes as the preparation is non-toxic. They were characterized using electron microscopy, zetasizer, UV⁻VIS spectrophotometry, and infrared spectroscopy. The optimum CNP-LAA-TQ size produced was 141.5 ± 7.8 nm, with a polydispersity index (PDI) of 0.207 ± 0.013. The encapsulation efficiency of CNP-LAA-TQ was 22.8 ± 3.2% for LAA and 35.6 ± 3.6% for TQ. Combined hydrophilic LAA and hydrophobic TQ proved that a myriad of highly efficacious compounds with poor systemic uptake could be encapsulated together in NP systems to increase their pharmaceutical efficiency, indirectly contributing to the advancement of medical and pharmaceutical sectors.

Preparation of acrylonitrile/acrylamide copolymer beads via a redox method and their adsorption properties after chemical modification

Poly(acrylonitrile-co-acrylamide) [poly(AN-co- AM)] was prepared via a redox method, with sodium bisulfite and potassium persulphate as the initiators. High yield was attained in up to 76% of monomer conversion within 3 h of reaction time. The copolymers were then chemically modified with hydroxylamine hydrochloride to obtain amidoxime functional groups in the polyacrylonitrile (PAN) system. The role of the amidoxime group is to form a chelating ion-exchange network based on acrylonitrile for the adsorption of heavy metal ions in aqueous solution. Based on the Fourier transform infrared spectra, the appearance of a strong band at the regions of 1680 and 3300–3400 cm-1 due to the stretching vibration of C=O and NH2 groups, respectively, confirmed the copolymerization of acrylamide into the PAN system. In the case of modified copolymers, there was an appearance of broad bands at the regions of ∼3300 and ∼900 cm-1, which corresponded to the stretching vibrations of O-H and =N-O, respectively, from the oxime group. The scanning electron microscopy showed that the average size of the copolymer particles was ∼149 nm, and the average size increased to ∼217 nm in the case of the modified copolymer. The amidoximed poly(AN-co-AM) was analyzed by inductively coupled plasma to investigate its adsorption behavior toward Cu(II).