Adsorption studies of some phenol derivatives onto Ag-cuttlebone nanobiocomposite: modeling of process by response surface methodology

Nanophotocatalytic degradation of phenolic contaminants by ZnS nanoparticles synthesized from banana peel extract: a greener approach

Research focused on the degradation of organic pollutants has seen considerable growth in recent years. The present investigations report a green chemistry route for the creation of ZnS nanoparticles (ZnS NPs) by employing the banana peel extract. X-ray diffraction analysis of the developed material established that the developed material has a cubic structure, while the FTIR spectrum of the fabricated ZnS NPs revealed the functional group present on the surface of the material exhibiting its suitability for the adsorption of the organic pollutant. SEM analysis of the material demonstrated the spherical particles with irregular morphology, and the average size of the material was estimated to be 52 nm. The fabricated ZnS NPs were utilized to capture the hazardous phenol and p-nitrophenol from wastewater. The influence of various process variables including the initial concentration of the pollutant, catalyst dose, pH, and contact time was examined to optimize the maximum efficiency of the photodegradation process. The optimum degradation of the p-nitrophenol and phenol was achieved to be 71% and 80%, respectively, under the specified condition; initial p-nitrophenol concentration 20 PPM, catalyst doses 0.6 gm/L, and the pH 10.

Ag/AgCl-NW/rGO composite for high-efficiency visible-light-driven photocatalytic activity of rhodamine B

One of the biggest environmental challenges still facing wastewater treatment is the efficient breakdown of dye pollutants such as rhodamine B (RhB). The development of effective photocatalysts that function in sunlight and visible light can greatly improve wastewater treatment systems. Combining reduced graphene oxide (rGO) with silver/silver chloride core-shell nanowires (Ag/AgCl-NW) might offer special optical and structural properties that enhance its photocatalytic activity for RhB degradation. Ag/AgCl-NW/rGO composite was produced by electroplating rGO onto stainless steel and then covering it with evenly dispersed Ag/AgCl-NW. In 120 min, the Ag/AgCl-NW/rGO composite degraded 99.78% of RhB (dye concentration of 10 ppm at pH 8) under visible light, following pseudo-first-order kinetics (rate constant: 0.0498 min⁻1) and maintaining its effectiveness for four reuse cycles. The photodegradation pathway is primarily dominated by direct chromophore degradation rather than the more typical de-ethylated rhodamine (Rh-110) pathway. Unlike RhB, Rh-110 is only produced when exposed to visible light, and it is completely oxidized in the presence of sunlight. These findings show the Ag/AgCl-NW/rGO composite to be a promising photocatalyst for effective RhB degradation in visible light and enhanced efficiency in sunlight, highlighting its potential for sustainable wastewater treatment applications.

Removal of Cr6+ in water by superoxide anion-mediated redox reaction assisted by lignin-rich kiwifruit twig biochar: Application of DFT calculation

This research aims to investigate the role of reactive oxygen species (ROS) in the adsorption and reduction of Cr6+ on lignin-rich biochar under dark conditions and under various oxygen treatment conditions. The research found that under aerobic conditions, the reduction content of Cr6+ (0.38 mg) and the production content of ·O2- (20.36 × 10-6 mg·L-1) are the highest, followed by untreated conditions (0.32 mg, 15.03 × 10-6 mg·L-1), and the lowest under anaerobic conditions (0.21 mg, 5.14 × 10-6 mg·L-1). Compared with anaerobic conditions, the reduction content of Cr6+ increased by 1.52 times under untreated conditions. Meanwhile, under anaerobic conditions, ·O2- disappeared, indicating that ·O2- had played an important role in the reduction of Cr6+. Kinetic results showed that the role of ·O2- in the reduction of Cr6+ mainly occurred in liquid solution. DFT calculations confirmed that C-OH was the main electron supplier in the reduction process of Cr6+, and there was a positive correlation between the production content of ·O2- and the content of C-OH in liquid solution. The present research is expected to provide a scientific basis for the transformation of Cr6+ on lignin-rich biochar in liquid solution.

A chitosan-based magnetic system for response surface methodology (RSM) optimization of the influencing variables in ciprofloxacin loading/releasing

We optimized the loading and release processes of Ciprofloxacin (CIP) on Fe3O4/Chitosan (FCS) magnetic nanoparticles (MNPs) for drug delivery applications. The Fe3O4 MNPs were synthesized via the coprecipitation method and subsequently coated with Chitosan to enhance their properties. Ciprofloxacin was used as a model drug. We characterized the structure, morphology, physicochemical, and magnetic properties of both the Fe3O4/CS MNPs and the CIP-loaded Fe3O4/CS MNPs using various techniques, including SEM, EDX, FTIR, XRD, VSM, TGA, and elemental mapping. In the spectrum of Fe3O4/CS/CIP, the appearance of absorption bands at 3437 cm-1 and 2908 cm-1 for -OH, and -NH2 functional groups of chitosan, the bands at 1378 cm-1 and 1066 cm-1 belong to its CH-OH and -C-O-C groups, and the bands at 1945 cm-1 and 1606 cm-1 of CIP carbonyl groups confirm modification of magnetite NPs by CS and loading CIP by the modified adsorbent. The average crystallite size was obtained about 20 nm based on the diffraction data. The modified adsorbent has a pHpzc of 6.1. The effects of different factors such as pH, time, temperature, and initial concentration on CIP's loading and release processes were studied using response surface methodology (RSM). Our findings indicated that the concentration of CIP was the most significant factor influencing the loading process, while time was the most crucial factor for the release process. The optimal conditions for loading were determined to be at pH 9 with a stirring time of 13 h, whereas the optimal conditions for release were at pH 2.7 with a stirring time of 9 h within a range of 1 to 9 h. One-factor-at-a-time studies indicated that a concentration of 20 ppm and an exposure time of 8 h had the most significant effects on loading and release, respectively.

KOH-treated tire pyrolyzed carbon as green and easily available adsorbent for Bisphenol A and Methylene blue adsorption

The occurrence of micropollutants and dyes in water sources has sparked alarm due to their significant impacts on aquatic ecosystems and human health. This study aims to utilize the tire pyrolyzed carbon (TPC) as a source of the adsorbent for removing Bisphenol A (BPA) and Methylene Blue (MB). The adsorbent was synthesized by chemical activation of TPC with KOH at 750 °C. The activated TPC was characterized for different physical and chemical characterization techniques such as XRD, FTIR, SEM, BET, XPS, and TPD and exhibits a higher adsorption capacity of 49.2 and 72.1 mg/g respectively for BPA and MB. The effect of initial concentration, dosage of adsorbent, and initial pH are evaluated for BPA and MB. The adsorption is mainly driven by hydrophobic, electrostatic, π-π interactions, and hydrogen bonding. The removal process follows the second order and Langmuir isotherms. The adsorbent shows excellent recyclability which makes it a potential source of removal of different water-borne pollutants. The production of activated carbon from tire waste is advocated for its economic and environmental benefits.

Development of an efficient hemostatic material based on cuttlefish ink nanoparticles loaded in cuttlebone biocomposite

Traumatic hemorrhage is one of the main causes of mortality in civilian and military accidents. This study aimed to evaluate the effectiveness of cuttlefish bone (cuttlebone, CB) and CB loaded with cuttlefish ink (CB-CFI) nanoparticles for hemorrhage control. CB and CB-CFI were prepared and characterized using different methods. The hemostasis behavior of constructed biocomposites was investigated in vitro and in vivo using a rat model. Results showed that CFI nanoparticles (NPs) are uniformly dispersed throughout the CB surface. CB-CFI10 (10 mg CFI in 1.0 g of CB) showed the best blood clotting performance in both in vitro and in vivo tests. In vitro findings revealed that the blood clotting time of CB, CFI, and CB-CFI10 was found to be 275.4 ± 12.4 s, 229.9 ± 19.9 s, and 144.0 ± 17.5 s, respectively. The bleeding time in rat liver injury treated with CB, CFI, and CB-CFI10 was 158.1 ± 9.2 s, 114.0 ± 5.7 s, and 46.8 ± 2.7 s, respectively. CB-CFI10 composite resulted in more reduction of aPTT (11.31 ± 1.51 s) in comparison with CB (17.34 ± 2.12 s) and CFI (16.79 ± 1.46 s) (p < 0.05). Furthermore, CB and CB-CFI10 exhibited excellent hemocompatibility. The CB and CB-CFI did not show any cytotoxicity on human foreskin fibroblast (HFF) cells. The CB-CFI has a negative surface charge and may activate coagulation factors through direct contact with their components, including CaCO3, chitin, and CFI-NPs with blood. Thus, the superior hemostatic potential, low cost, abundant, simple, and time-saving preparation process make CB-CFI a very favorable hemostatic material for traumatic bleeding control in clinical applications.

Optimization and characterization of silver nanoparticle-modified luffa for the adsorption of ketoprofen and reactive yellow 15 from aqueous solutions

In the current work, luffa was modified with silver nanoparticles to prepare LF/AgNPs adsorbent for the elimination of ketoprofen and reactive yellow 15 (RY15) from aqueous media. Various characterization techniques, including FT-IR, XRD, BET, and SEM-EDS analysis, were employed to confirm the successful modification of LF/AgNPs. Several key parameters such as contact time, adsorbent dosage, concentration, pH, and agitation technique were fine-tuned to optimize the adsorption process. Ketoprofen removal was found to be most effective in weakly acidic conditions (pH = 5), while reactive yellow 15 adsorption was enhanced in an acidic environment (pH = 2). At 298 K, the highest adsorption capacities reached 56.88 mg/g for ketoprofen and 97.76 mg/g for reactive yellow 15. In both scenarios involving the elimination of ketoprofen and RY15, the Temkin isotherm exhibits higher R2 values, specifically 0.997 for ketoprofen and 0.963 for RY15, demonstrating a strong correlation with the observed adsorption data. Additionally, the kinetics of ketoprofen adsorption were best described by the Pseudo-first order model (R2 = 0.989), whereas the Pseudo-second order model provided the most accurate fit for reactive yellow 15 adsorption (R2 = 0.997). Importantly, the LF/AgNPs adsorbent displayed consistent performance over five consecutive reuse cycles, affirming its stability and efficacy in removing both contaminants. These findings underscore the exceptional potential of LF/AgNPs as a reliable adsorbent for the removal of reactive yellow 15 and ketoprofen from aqueous solutions.

Preparation and characterization of graphitic carbon nitrides/polyvinylidene fluoride adsorptive membrane modified with chitosan for Rhodamine B dye removal from water: Adsorption isotherms, kinetics and thermodynamics

In the present study, a PVDF/g-C₃N₄/chitosan (PCC) membrane was used for the removal of Rhodamine B from aqueous solutions. Water flux for PCC membrane decreased from 49.87% to 14.76% by the addition of chitosan from 2% to 4%. Afterward, batch adsorption conditions were optimized for a PVDF/g-C₃N₄/chitosan membrane applying Box-Behnken design algorithm. The maximum RB removal efficiency was 72.74% at 2 mg/L of initial RB concentration, pH = 3, 2 g of g-C₃N₄ and 3% of chitosan at the optimum conditions. The Freundlich isotherm and pseudo-second order models were satisfactorily describing the equilibrium and kinetic of adsorption, respectively. Thermodynamic parameters were disclosed that the adsorption of RB onto PCC was exothermic (ΔH° = -21.35 kJ mol^-1) and spontaneous (ΔG° < 0) with the generation of energy (ΔS° = +92.42 kJ mol^-1) at the interface of solid/liquid. Thus, this novel membrane could be employed as an effective adsorbent to remove of RB dye from aqueous solutions.

Arsenate removal from aqueous solutions by cuttlebone/copper oxide nanobiocomposite

This study aims to illustrate the preparation of a new nanobiocomposite by incorporating copper oxide nanoparticles into cuttlebone matrix (CB/CuO NPs), and it was tested to define how effective it was to adsorb and remove arsenate from aqueous systems. CB is the bone tissue of cuttlefish with high porosity, permeability, and low cost. CuO NPs have been introduced as an effective arsenate adsorbent. Producing nanocomposite by introducing of CuO NPs in the structure of CB enhanced their stability and facilitated their separation from solution. Incorporation of CuO NPs in the structure of CB enhanced the adsorption capacity of CB. The adsorption data were fitted with both Langmuir and Freundlich isotherms, but Langmuir isotherm exhibited better matching rather than Freundlich isotherm. The maximum adsorption capacity (q_max) was calculated from Langmuir adsorption isotherm which was around 25.13 mg g^-1. Kinetic data fitted well to the pseudo-second-order reaction model. The results indicate that the possible mechanism of arsenate adsorption on CB/CuO is through development of inner sphere complex. Simple preparation and abundant and good adsorption capacity in the presence of calcium ions indicate that the CB/CuO is suitable for removal of arsenate from contaminated drinking water.