Stability of Insulin on Polycaprolactone Nanoparticles as a Function of Surface Properties

The purpose of this research was to formulate insulin-loaded polycaprolactone (PCL) nanoparticles and evaluate structural stability of the protein using fluorescence spectroscopy. The size and morphology of the nanoparticles were characterized using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Fluorescence emission data revealed that insulin is most stable with multilayer adsorption at pH close to its isoelectric point (IEP). The obtained particle size ranged from 130-140 nm+22 (SD). The loading amount of insulin onto the PCL nanoparticles was low at pH 7.4 and relatively high at pH 5.3. The adsorption phenomenon of protein onto hydrophobic nanoparticles provides a promising noninvasive carrier system for insulin.

The usage of lignin in two significant applications: As adsorbent surface of water pollutants and antioxidant of plastic polymers: short review

Since pollution is very serious problem threating the environmental eco-system around the world, but people do not usually treat this issue properly. Water is contaminated with different type of pollutants such as organic, inorganic, heavy metals, pesticides, dyes, phenols, and many other pollutants. Using adsorption phenomenon is very practical, easy and common method to remove pollutants from water. Owing to the significant properties of lignin such as high surface area, porosity, availability in huge amount, it was chosen to be used as an adsorbent surface of various pollutants. Herein it is going to review some of important literatures regarding that. Another serious problem that is threatening the marine eco-system, human health, and influence the global warming is the huge consumption of plastic polymers every year. Thus, reducing the consumption of plastic polymers is significantly matter. Lignin chemical structures are highly oxygenated and have several aromatic units, so by definition lignin can act as an antioxidant, free radical scavenger and photo-stabilizers. As the chemical structure of monomer moieties to form lignin are highly aromatic so it is suitable to work as UV- blocker to stop the photo-degradation of plastic.

Probing Critical Physical Properties of Lactose-Polyethylene Glycol Microparticles in Pulmonary Delivery of Chitosan Nanoparticles

Pulmonary delivery of chitosan nanoparticles is met with nanoparticle agglomeration and exhalation. Admixing lactose-based microparticles (surface area-weighted diameter~5 μm) with nanoparticles mutually reduces particle agglomeration through surface adsorption phenomenon. Lactose-polyethylene glycol (PEG) microparticles with different sizes, morphologies and crystallinities were prepared by a spray drying method using varying PEG molecular weights and ethanol contents. The chitosan nanoparticles were similarly prepared. In vitro inhalation performance and peripheral lung deposition of chitosan nanoparticles were enhanced through co-blending with larger lactose-PEG microparticles with reduced specific surface area. These microparticles had reduced inter-microparticle interaction, thereby promoting microparticle–nanoparticle interaction and facilitating nanoparticles flow into peripheral lung.

Potassium Adsorption Phenomenon in Calcareous Soils of Shahrazur Plain

A laboratory study for adsorption of potassium (K) determination was conducted on six soils located in Sharazur plain from the Kurdistan Region of Iraq in 2021 using the batch technique method. Potassium (K) adsorption isotherms were achieved by equilibrating 5.0 g of soil samples with eight grades of K (0 to 300 mg L-1) as KCl in 50 ml of 0.01M CaCl2 solution. To match the data of adsorption, Freundlich, Langmuir, and Temkin adsorption isotherms were used. The results show that the amount of adsorbed K ranged between (45.78 to 52.49) % added K. The Freundlich model fit the equilibrium K adsorption data better for the Serwan location of soil (silty loam), as demonstrated by a greater coefficient of determination (R2 =0.90). The value of heterogeneity factor 1/n for the Freundlich model ranged from (0.34 to 0.47) kg mg-1, which was less than one. The sorption processes for all of the studied soils were normal adsorption. The constant of the Langmuir isotherm (KL) aligned from (0.107 to o.425) L mg-1. Smaller KL values mean that more adsorbed K would be transformed to a non-exchangeable form, either through the creation of crystalline K or through ion occultation. The RL values indicate the type of isotherm, the values of RL> 1 that means the adsorption nature to be unfavorable. The Temkin equilibrium binding constant (AT) was high for all studied soils except the soils of Bestan Sur and Grdigo locations, the high value of AT indicates high binding energy. The Temkin constant (bT) ranged from (10.46 to 13.47) J mole-1 that was related to the nature of the adsorption energy, a positive value indicates that the adsorption process is exothermic.

A Model for Bias Potential Effects on the Effective Langmuir Adsorption–Desorption Processes

We discuss the foundations of a model based on an extension of the Langmuir approximation for the adsorption–desorption phenomena, in which the phenomenological coefficients depend on the bias potential, in addition to their dependence on the adsorption energy. The theoretical analysis focuses on the effect of these effective coefficients on the electrical response of an electrolytic cell to an external electric field, as predicted by the Poisson–Nernst–Planck model. Kinetic balance equations govern the current densities on the electrodes when the adsorption phenomenon occurs in the presence of an electric bias. The influence of the phenomenological parameters entering the model, as well as of the symmetry of the cell on the cyclic voltammetry, is investigated.

Selective Removal of Hg2+ Ions from Water Using New Functionalized Silica Resin: Equilibrium, Thermodynamics and Kinetic Modeling Studies

In current study, the diphenylaminomethylcalix[4]arene (3) was synthesized and immobilized onto silica surface to prepare a selective, regenerable and stable resin-4. The synthesized resin-4 has been characterized by FT-IR spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX) and Brunauer-Emmett-Teller (BET) techniques. To check the adsorption capacity of resin-4, the batch and column adsorption methodology were applied and it has observed that the resin-4 was selectively removed Hg2+ ions under the optimized parameters. The maximum adsorption capacity was obtained at pH 9 using 25 mg/L of resin-4. Under the optimal conditions, different equilibrium, kinetic and thermodynamic models were applied to experimental data. The results show that adsorption mechanism is chemical in nature following Langmuir model with good correlation coefficient (R2=0.999) and having 712.098 (mmol/g) adsorption capacity. The energy of calculated from D-R model suggests the ion exchange nature of the adsorption phenomenon. Dynamic adsorption experiments were conducted using Thomas model. The maximum solid phase concentration (qo) was 7.5 and rate constant was found to be 0.176 with (R2=0.938) for Hg2+ ions. The kinetic study describes that the adsorption mechanism follows pseudo second order (R2=0.999). The thermodynamic parameters such as ∆H (0.032 KJ/mol) and ∆S (0.127 KJ/mol /K) and ∆G (-5.747,-6.306, -7.027 KJ/mol) shows that the adsorption of Hg2+ ion is endothermic and spontaneous. The reusability of resin-4 was also checked and it has observed that the after 15 cycle only 1.2 % adsorption reduces. Moreover, the resin-4 was applied on real wastewater samples obtained from local industrial zone of Karachi, Sindh-Pakistan.

The spectral study of azo dye and cationic surfactant interaction in ethanol-water mixture

The interaction of azo dye methyl red (MR) with dodecyl trimethyl ammonium bromide (DTAB) has been studied spectrophotometrically through azo-hydrazone tautomeric behavior of MR for a series of the ethanol-water system (0.1, 0.2, 0.3 and 0.4 volume fractions of ethanol) at room temperature. Critical micelle concentration was determined using the conductometric technique with increased ethanol volume influenced by solvent polarity and architectural flexibility of methyl red. The azo form of methyl red brings electrostatic interaction with cationic surfactant through the adsorption phenomenon. The binding parameters were calculated with the aid of a modified Benesi-Hildebrand equation.

Carbon Dioxide (CO2) Capture in Alkanolamines Impregnated Activated Carbon Developed from Date Stones

The concern to reduce global carbon emissions has significantly improved the development of efficient solid sorbents such as activated carbon (AC). In this study, AC is developed from date stones which is one of the abundantly found agricultural waste material in gulf region. The AC was completely characterized in terms of pore volume, surface area, stability test, volatile carbon and fixed carbon contents. Impregnation of AC was performed by three different alkanolamines, namely Diethylene triamine (DETA), Pentaethylene hexamine (PEHA) and Di-ethanol amine (DEA). The alkanolamine impregnated sorbents were utilized for CO2adsorption at temperatures of 25, 30, 40, 50, 60, 70 and 100 °C and carbon dioxide (CO2) concentrations of 10, 30, 50, 70 and 92% in helium. The adsorption phenomenon was evaluated by Langmuir isotherms for all the studied adsorbents. The AC developed from date stones provided high adsorption loading capacity of CO2 i.e., 89.79 mg/g of AC at 25 °C. Thermodynamic parameters showed that the adsorption was endothermic and spontaneous in nature. Moreover, desorption profiles reveal that DETA-AC samples provided most favorable characteristics with respect to the value of desorption constant.

Thermodynamic Analysis of Moisture Adsorption of Taraxacum Officinale’ Powder

This work aims to model the adsorption isotherms and study the essential thermodynamic properties of Taraxacum Officinale’ powder during the moisture adsorption phenomenon at three temperatures 30, 40, and 50°C. The results have been determined by the application of the thermodynamics physical principles to the equilibrium data, which are experimentally measured. The estimated values of the isokinetic and harmonic temperatures and the Gibbs free energy change revealed that the sorption process is non-spontaneous and enthalpy driven.