Synthesis of Co3O4@SiO2 Core/Shell–Nylon 6 Magnetic Nanocomposite as an Adsorbent for Removal of Congo Red from Wastewater

Removal of sarafloxacin from aqueous solution through Ni/Al-layered double hydroxide@ZIF-8

In recent years, excessive amounts of drugs such as antibiotics have been used to combat COVID-19 and newly discovered viruses. This has led to the production and release of significant amounts of drugs and their metabolites as toxic pollutants in aquatic systems. Therefore, pharmaceutical wastes must be removed efficiently before entering the environment and entering water sources. In this research, Ni/Al-LDH@ZIF-8 nanocomposite was synthesized from layered double hydroxides and metal-organic frameworks and used to remove the antibiotic sarafloxacin (SRF) in the aqueous medium. The work aimed to develop the performance and combine the features of the adsorbent compounds such as high surface area, adjustable porosity, and low-density structure. Different methods implemented to analyze the nanocomposite, such as Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. The experiment utilized the central composite design to evaluate statistics and the response level method to optimize the factors affecting the absorption process. The initial concentration of SRF, adsorbent dose, pH, and contact time were considered in this experiment. The results showed an increase in the removal efficiency of SRF to 97%. Statistical studies showed that the optimal adsorption conditions are as follows: initial concentration of SRF 40 mg·L-1, pH 6.3, adsorbent dose of Ni/Al-LDH@ZIF-8 49 mg, and contact time of 44 min. According to the model of isotherms parameters, the adsorption process is more consistence with the Freundlich model with the absorption capacity of 79.7 mg·g-1. The pseudo-second-order model described the adsorption kinetics data.

Graphical abstract

Study adsorbents based on bent-Al13-CS-CTA and its application to the removal of CR from wastewater

For rapid and efficient removal of Congo red (CR) from aqueous solutions, a composite of bent-Al13-CS-CTA was prepared from bentonite (bent), chitosan (CS), citric acid (CTA) and Al13 compounds. To comprehend the adsorption process, adsorption variables were changed, including initial pH of the solution, contact time, temperature, initial CR concentration, and adsorption dose. Bent intercalated with X-ray diffraction (XRD), specific surface area (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR) were used to analyze the material. Physicochemical and structural analysis proven the incorporation of Al13, CS, and CTA into the bent matrix. The pseudo-second-order model aligns with the adsorption kinetics. The adsorption isotherm conformed to the Langmuir adsorption isotherm, with a maximum adsorption capacity of 476.8 mg g-1 at pH 9, a dosage of 2 g L-1, and a temperature of 25 °C. Upon examining the thermodynamic properties of ΔS, ΔH, and ΔG, it was found that the reaction is a spontaneous endothermic process that could potentially be utilized to eliminate CR.

Nylon fiber waste as a prominent adsorbent for Congo red dye removal

In this research nylon fibers wastes (NF) were fabricated into porous sheet using a phase inversion technique to be utilized as an adsorbent materials for Congo red dye (CR). The fabricated sheet denoted as NS was characterized using FTIR and XRD. The surface studies of the adsorbent materials using SEM and BET analysis reveals a highly pores structure with an average pore volume 0.61 cc/g and BET surface area of 767 m2/g. The adsorption studies of fabricated NS were employed into CR at different parameters as pH, effect of time and dye concentration. The adsorption isotherm and kinetic studies were more fit to Langmuir and pseudo second order models. The maximum adsorption capacity qmax reached 188 mg/g with removal percentage of 95 for CR concentration of 400 mg/L at pH 6 and 0.025 g NS dose for 10 ml CR solution. The regeneration study reveals a prominent adsorption behavior of NS with removal % of 88.6 for CR (300 mg/L) after four adsorption desorption cycles. Effect of incorporation of NaonFil Clay to NS was studied using Response Surface Methodology (RSM) modeling and reveals that 98.4% removal of CR could be achieved by using 19.35% wt. of fiber with 8.2 g/L dose and zero clay, thus at a predetermined parameters studies of NanoFil clay embedded into NS, there are no significant effect for %R for CR.

Interfacial charge transfer of Carrisa edulis fruit extract capped Co3O4 nanoparticles on the surface of MK30: An efficient photocatalytic removal of methylthioninium chloride and tetracycline organic pollutants

The in-depth usage of organic pollutants by pharmaceutical industries constitutes a major contaminant to the bodies of water due to their solubility, great mobility, ability to get attached to water bodies for a long period of time, and low biodegradability. Due to these, it may further cause disease and change the ecosystem of aqueous and other living organisms. Accordingly, effective removal of organic contaminants from waste water is a vital step in reducing the hazards. Photocatalysis is a potential technique for removing hazardous organic pollutants from wastewater. In this work, a simple ultra-sonication assisted approach, a series of Carrisa edulis fruit extract capped Co₃O₄ nanoparticles decorated on Montmorillonite K30 nanosheets (Co₃O₄/MK30) were prepared. The inherent physicochemical appearance and optical properties of as-prepared nanomaterials were investigated using a variety of analytical techniques. TEM analysis depicted the spherical shape of the Co₃O₄ NPs with the size of 11.25 nm. The degradation of methylthioninium chloride as a dye and tetracycline drug pollutants has been investigated in this study using individual and simultaneous photocatalysis systems in the presence of pure Co₃O₄ NPs and different ratios of Co₃O₄/MK30 nanocomposites. Owing to the generation of OH and O₂ radicals, the 20% loaded Co₃O₄ on MK30 had the best photocatalytic performance of methylthioninium chloride (98.12%) and tetracycline degradation (87.4%), on exposing it to visible light. This research introduces a new design for MK30-based nanomaterials and proposes its use in environmental challenges.

Magnetic Nylon 6 Nanocomposites for the Microextraction of Nucleic Acids from Biological Samples

Magnetic Fe3O4 nanoparticles (MNPs) have great potential for nucleic acid separation, detection, and delivery. MNPs are considered a valuable tool in biomedicine due to their cost-effectiveness, stability, easy surface functionalization, and the possibility of the manipulations under a magnetic field. Herein, the synthesis of magnetic nylon 6 nanocomposites (MNPs@Ny6) was investigated. Transmission electron microscopy (TEM) was used for morphology and size analysis. A new method of UV-induced immobilization of oligonucleotides on MNPs@Ny6 for nucleic acid magnetic separation was proposed. MNPs@Ny6 shows a high oligonucleotide binding capacity of 2.2 nmol/mg with 73.3% loading efficiency. The proposed system has been applied to analyze model mixtures of target RNA on the total yeast RNA background. The RNA target isolation efficiency was 60% with high specificity. The bind RNA release was 88.8% in a quantity of 0.16 nmol/mg. The total RNA capture efficiency was 53%. Considering this, the MNPs@Ny6 is an attractive candidate for nucleic acids-specific magnetic isolation.

Synthesis of MgNiCo LDH hollow structure derived from ZIF-67 as superb adsorbent for Congo red

Adsorption materials with large specific surface area and porous structures exert a beneficial impact on improving the adsorption performance. In this work, MgNiCo LDH hollow structure (MNC HS) is fabricated through a simple one-step solvothermal method using ZIF-67 as the sacrificial template. Electron microscopy shows that the MNC HS retains the dodecahedral shape of ZIF-67. The as-prepared sample exhibits efficient adsorption for Congo red (CR) in water, which is due to the hierarchical structure and large specific surface area that provides more adsorption sites and electrostatic interaction. The CR adsorption process fits the pseudo-second-order model better by kinetics simulation; while Langmuir model is more accurate than Freundlich model in describing the adsorption isotherms of CR. The maximum adsorption capacity calculated by the Langmuir model can reach 1194.7 mg g^-1, which is much higher than that of the sample MgNiCo LDH (MNC) synthesized by conventional methods. The cycle tests also show that the as-prepared adsorbent has good stability and recycling ability.

Elimination of Congo Red Dye from Industrial Wastewater Using Teucrium polium L. as a Low-Cost Local Adsorbent

A novel adsorbent prepared from the leaf powder of Teucrium polium L. (TPLLP) was characterized and its ability for adsorption of Cong red (CR) was inspected. Influences of CR concentration, adsorbent dosage, time of agitation, pH of solution, and temperature on the performance of this adsorption were also examined. Three models of kinetic along with three different isotherm models were applied for analyzing the empirical data of this adsorption. Additionally, the thermodynamic constants of were decided. The surface area, pore volume, pore size, and pHZPC of Zn/Cu-TPLLP were found to be 2.6436 m2.g-1, 0.013317 cm3.g-1, 527.393 Å, and 8.8, respectively. The achieved outcomes indicate the positive influence of temperature, concentration of CR in the range of 20 to 900 mg/L, adsorbent mass in the range of 0.005 to 0.02 g, time of adsorption from 0 to 120 min, and pH from 5.5 to 8.5. Models of the 2nd order with $R^2\ge 0.995$ and Langmuir with $R^2\ge 0.990$ were the best among the other kinetic and isotherm models applied in this research. Moreover, superior capacities of 526.32, 666.67, and 909.09 (mg.g-1) were stemmed at 27, 42, and 57°C, respectively. The outcomes of the thermodynamic evidenced that this adsorption is spontaneous and a heat absorber.