Box–Behnken Statistical Design for Removal of Methylene Blue from Aqueous Solution Using Sodium Dodecyl Sulfate Self-microemulsifying Systems

Application of green nanoemulsion to treat contaminated water (bulk aqueous solution) with azithromycin

The present work aimed to remove azithromycin (AZM) from the contaminated aqueous system using a water/ethanol/transcutol/Capryol-90 green nanoemulsion. The drug is identified as a potential pharmaceutical contaminant detrimental for flora and fauna of aquatic lives as well as human health. Green nanoemulsions were tailored and characterized for thermodynamic stability, size, polydispersity index (PDI), zeta potential, viscosity, refractive index (RI), and morphological assessment using a transmission electron microscopy (TEM). Moreover, nanoemulsions were investigated for percent removal efficiency (%RE) and factors affecting percent removal efficiency (%RE). The results suggested that the developed green nanoemulsions (ANE1-ANE5) were transparent (˂ 200 nm) and stable. ANE5 exhibited the lowest value of globular size (49 nm), PDI (0.17), viscosity (~ 93 cP), and optimum zeta potential (-27.8 mV). The value of %RE depended upon the content of water and Capryol-90 of the nanoemulsion. Furthermore, the value of %RE was found to be increased with increased content of water, whereas this was decreased on increasing the Capryol-90 content in the nanoemulsions. Similarly, on decreasing the values of size and viscosity, the %RE values were observed to be increased. There was insignificant impact of the duration of exposure time on %RE. Thus, the maximum %RE value (96.8%) was obtained by ANE5 from the aqueous solution after 20 min of contact time with ANE5. Thus, this method could be a promising approach to remove AZM from the contaminated water and serve as an alternative to conventional methods.

Application of Green Nanoemulsion for Elimination of Rifampicin from a Bulk Aqueous Solution

The study aimed to prepare green nanoemulsion (GNE) multi-components ((water/dimethyl sulfoxide-transcutol/isopropyl alcohol/capmul MCM C8 (CMC8)) to remove rifampicin (RIF) from a contaminated aqueous bulk solution. Pseudo ternary phase diagrams dictated several batches of GNE prepared following the reported method. Selected nanoemulsions (NF1-NF5) were characterized for morphology, globular size, size distribution (polydispersity index, PDI), viscosity, zeta potential, refractive index (RI), and free-thaw kinetic stability. They were investigated for percent removal efficiency (%RE) of RIF from the bulk aqueous solution for varied time intervals (10-60 min). Finally, scanning electron microscopy-energy dispersive x-ray (SEM-EDX) and inductive coupled plasma-optical emission system (ICP-OE) were used to confirm the extraction of trace content of dimethyl sulfoxide (DMSO) and others in the treated water. Considering the data obtained for globule size, PDI, viscosity, zeta potential, freeze-thaw stability, and refractive index, NF5 was the most suitable for RIF removal. The largest %RE value (91.7%) was related to NF5, which may be prudent to correlate with the lowest value (~39 nm) of size (maximum surface area available for contact adsorption), PDI (0.112), and viscosity (82 cP). Moreover, %RE was profoundly influenced by the content of CMC8 and the aqueous phase. These two phases had immense impact on the viscosity, size, and RI. The percent content of water, Smix, and CMC8 were 15% w/w), 60% w/w, and 25% w/w, respectively in NF5. SEM-EDX and ICP-OE confirmed the absence of DMSO and other hydrophilic components in the treated water. Thus, efficient NF5 could be a promising option to the conventional method to decontaminate the polluted aqueous system.

Spectrophotometric determination of anionic surfactants: optimization by response surface methodology and application to Algiers bay wastewater

A simple analytical method for quantitative determination of an anionic surfactant in aqueous solutions without liquid-liquid extraction is described. The method is based on the formation of a green-colored ion associate between sodium dodecylbenzenesulfonate (SDBS) and cationic dye, Brilliant Green (BG) in acidic medium. Spectral changes of the dye by addition of SDBS are studied by visible spectrophotometry at maximum wave length of 627 nm. The interactions and micellar properties of SDBS and cationic dye are also investigated using surface tension method. The pH, the molar ratio ([BG]/[SDBS]), and the shaking time of the solutions are considered as the main parameters which affect the formation of the ion pair. Determination of AS in distilled water gives a significant detection limit up to 3 × 10^-6 M. The response surface methodology (RSM) is applied to study the absorbance. A Box-Behnken is a model designed to the establishment of responses given by parameters with great probability. This model is set up by using the three main parameters at three levels. Analysis of variance shows that only two parameters affect the absorbance of the ion pair. The statistical results obtained are interesting and give us real possibility to reach optimum conditions for the formation of the ion pair. As the proposed method is free from interferences from major constituents of water, it has been successfully applied to the determination of anionic surfactant contents in wastewaters samples collected from Algiers bay.

Response surface methodology as a powerful tool to optimize the synthesis of polymer-based graphene oxide nanocomposites for simultaneous removal of cationic and anionic heavy metal contaminants

Nanocomposites containing graphene oxide (GO), polyethyleneimine (PEI), and chitosan (CS) were synthesized for chromium(vi) and copper(ii) removal from water.

Photodegradation of Eosin Y Using Silver-Doped Magnetic Nanoparticles

The purification of industrial wastewater from dyes is becoming increasingly important since they are toxic or carcinogenic to human beings. Nanomaterials have been receiving significant attention due to their unique physical and chemical properties compared with their larger-size counterparts. The aim of the present investigation was to fabricate magnetic nanoparticles (MNPs) using a coprecipitation method, followed by coating with silver (Ag) in order to enhance the photocatalytic activity of the MNPs by loading metal onto them. The fabricated magnetic nanoparticles coated with Ag were characterised using different instruments such as a scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDAX) spectroscopy, and X-ray diffraction (XRD) analysis. The average size of the magnetic nanoparticles had a mean diameter of about 48 nm, and the average particle size changed to 55 nm after doping. The fabricated Ag-doped magnetic nanoparticles were used for the degradation of eosin Y under UV-lamp irradiation. The experimental results revealed that the use of fabricated magnetic nanoparticles coated with Ag can be considered as reliable methods for the removal of eosin Y since the slope of evaluation of pseudo-first-order rate constant from the slope of the plot between ln⁡(C_o/C) and the irradiation time was found to be linear. Ag-Fe₃O₄ nanoparticles would be considered an efficient photocatalyst to degrade textile dyes avoiding the tedious filtration step.