Synthesis of novel magnesium ferrite Schiff base chitosan nanocomposite for efficient removal of pb(II) ions from aqueous media

In this study, a novel MgFe2O4-Schiff base-chitosan nanocomposite was synthesized using a straightforward crosslinking method. The synthesis involved integrating MgFe2O4 nanoparticles with modified chitosan through a Schiff base formed by the reaction between terephthalaldehyde and aminopyrazine. A comprehensive characterization was performed, including X-ray diffraction analysis, which verified the crystalline structure and the successful incorporation of MgFe2O nanoparticles into the chitosan-Schiff base matrix. Scanning electron microscopy revealed a distinct surface morphology, characterized by a rough, non-uniform alignment resulting from the strong interactions between the nanoparticles and the Schiff base-chitosan matrix. Additionally, energy-dispersive X-ray analysis verified the elemental composition of the nanocomposite, revealing distinct peaks corresponding to carbon, nitrogen, oxygen, magnesium, and iron. The nanocomposite exhibited outstanding performance as a nanoadsorbent for the efficient removal of Pb(II) ions from aqueous media through electrostatic attraction and complexation mechanisms, achieving a maximum adsorption capacity of 290.7 mg g-1. The adsorption process was determined to be spontaneous, endothermic, and chemically driven, aligning well with the Langmuir isotherm model and pseudo-second-order kinetics. The optimal conditions for maximum Pb(II) ions removal were determined to be a pH of 5.5, a contact time of 100 min, and a temperature of 328 K. Furthermore, the nanocomposite demonstrated excellent recyclability, retaining over 94.8% of its initial removal efficiency after five consecutive adsorption-desorption cycles. This study highlights the nanocomposite's potential as an eco-friendly, cost-effective, and highly efficient material for practical applications in water treatment, addressing the urgent need for sustainable solutions to heavy metal contamination.

Peroxydisulfate activation by synergized modified AgCuFe2O4@GO nanoparticle electrode with anchored MnO2 in cefixime three-dimensional electrochemical degradation: Optimization and mechanisms

Cefixime (CFX) is a potent antibiotic against gram-positive and gram-negative bacteria that resists degradation and typical removal procedures. This research aimed to synthesize a modified AgCuFe2O4@GO nanoparticle electrode with anchored MnO2 for removing CFX by three-dimensional electrochemical oxidation. The physical and chemical characteristics of the nanocomposite were evaluated using various techniques, including FESEM, XRD, EDS-mapping, FTIR, BET, VSM, and TGA. The analysis found that the AgCuFe2O4@GO with anchored MnO2 nanoparticle electrode has a large specific surface area, acceptable crystal structure, good magnetic characteristics, and a quasi-spherical form. At pH 5, 40 mg/L of CFX concentration, 0.4 g/L of the nanocomposite, 3 cm of electrode interval, 0.12 mM of persulfate electrolyte, and 12.5 mA/cm2 of current density for 40 min, the process reached removal effectiveness of 97.1% for the synthetic sample and 90.7% removal efficiency for the actual sample, while had rate mineralization of 61.8% and 241.1 kWh/g energy consumption. Pseudo-first-order (R2 = 0.997) and Langmuir-Hinshelwood (R2 = 0.769) kinetic experiments provided values of KC = 7.788 mg/L.min and KL-H = 0.011 L/mg, respectively, confirming conformity to these models. The adsorption isotherms demonstrated that the CFX antibiotic complies with the Temkin model with an R2 of 0.959. The particle electrode eliminated 86.1% of the contaminant over five cycles of regeneration and recovery, showcasing outstanding chemical stability. Throughout this process, persulfate functioned as both an oxidizing agent and an electrolyte, so amplifying the production of active radicals that degrade the pollutant and improve removal efficiency. Due to its magnetic properties, chemical stability, reusability, and high efficiency, modified AgCuFe2O4@GO with anchored MnO2 is suggested for purifying industrial and medicinal wastewater.

Behaviour and mechanics of phenolic sorption by novel bio-based graphene derivatives as adsorbents

Phenolic compounds, notorious for their environmental and health hazards, demand efficient removal from wastewater. Our research leads in synthesizing bio-based graphene derivatives from biomass-derived lignin, such as graphene oxide (bGO) and reduced graphene oxide (brGO), and these materials show promise in effectively removing hydrophobic pollutants like phenol and tannic acid. Hence, this study investigated the mechanical and dynamical aspects of their sorptions by bGO and brGO. Both adsorbents demonstrated a comparable adsorption pattern, with enhanced efficiency observed at higher adsorbent dosage, prolonged contact time, neutralized pH solutions, and elevated temperatures. Of note, phenol is removed at a much greater rate (>94%) than tannic acid (>84%) by both adsorbents at a dosage of 180 mg L-1, pH 6.5, 900 min, and 25 °C. The Freundlich model provided the best fit for the isotherm data of both phenol (R2 = 0.99) and tannic acid (R2 = 0.98), while the pseudo-second-order model effectively described the adsorption kinetics of phenol (R2 = 0.99) and tannic acid (R2 = 0.99). The determined activation energy exceeds 5.88 kJ mol-1, affirming the prevalence of physisorption as the dominant mechanism in the adsorption process. Thermodynamic analysis confirmed that the adsorption process is endothermic (ΔH) and occurs spontaneously (ΔG), indicating a random (ΔS) nature. However, the percentage removal plunged considerably after five consecutive adsorption-desorption cycles, attributed to the alterations of active sites on bGO and brGO.

Advances in three-dimensional electrochemical degradation: A comprehensive review on pharmaceutical pollutants removal from aqueous solution

Water pollution, stemming from various contaminants including organic and pharmaceutical pollutants, poses a significant global challenge. Amidst the array of methods available for pollutant mitigation, the three-dimensional electrochemical approach emerges as a standout solution due to its environmental compatibility, cost-effectiveness, and rapid efficiency. This study delves into the efficacy of three-dimensional electrochemical processes in purging organic and pharmaceutical pollutants from aqueous media. Existing research indicates that the three-dimensional electrochemical process, particularly when employing particle electrodes, exhibits notable success in degrading organic and pharmaceutical pollutants. This achievement is largely attributed to the ample specific surface area of particle electrodes and the shortened mass transfer distance, which collectively enhance efficiency in comparison to traditional two-dimensional electrochemical methods. Moreover, this approach is lauded for its environmental friendliness and cost-effectiveness. However, it is imperative to note that the efficacy of the process is subject to various factors including temperature, pH levels, and current intensity. While the addition of oxidants can augment process efficiency, it also carries the risk of generating intermediate compounds that impede the reaction. In conclusion, the three-dimensional electrochemical method proves to be a viable and practical approach, provided that process conditions are meticulously considered and adhered to. Offering advantages from both environmental and economic perspectives, this method presents a promising alternative to conventional water and wastewater treatment techniques.

Bisphenol A adsorption using modified aloe vera leaf-wastes derived bio-sorbents from aqueous solution: kinetic, isotherm, and thermodynamic studies

Reactive-oxygen-species are produced more often in the body when bisphenol A (BPA), an endocrine-disrupting-substance, is present. In this investigation, bio-sorbents from an aqueous solution adapted from Aloe-vera were used to survey BPA removal. Aloe-vera leaf wastes were used to create activated carbon, which was then analyzed using Fourier transform infrared (FTIR), Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Zeta potential, and Brunauer-Emmett-Teller (BET) techniques. It was revealed that the adsorption process adheres to the Freundlich isotherm model with R2>0.96 and the pseudo-second-order kinetic model with R2>0.99 under ideal conditions (pH = 3, contact time = 45 min, concentration of BPA = 20 mg.L-1, and concentration of the adsorbent = 2 g.L-1). After five-cycle, the efficacy of removal was greater than 70%. The removal of phenolic-chemicals from industrial-effluent can be accomplished with the assistance of this adsorbent in a cost-effective and effective-approach.

An effective magnetic nanobiocomposite: Preparation, characterization and its application for adsorption removal of P-nitroaniline from aquatic environments

In this investigation, a magnetic nanobiocomposite, denoted as CoFe2O4/Activated Carbon integrated with Chitosan (CoFe2O4/AC@Ch), was synthesized based on a microwave-assisted for the efficacious adsorption of P-nitroaniline (PNA). The physicochemical properties of the said nano biocomposite were thoroughly characterized using a suite of analytical methodologies, namely FESEM/EDS, BET, FTIR, XRD, and VSM. The results confirm the successful synthesis of the nanobiocomposite, with its point of zero charge (pHZPC) determined to be 6.4. Adsorptive performance towards PNA was systematically examined over a spectrum of conditions, encompassing variations in PNA concentration (spanning 10-40 mg/L), adsorbent concentration (10-200 mg/L), contact periods (2.5-22.5 min), and solution pH (3-11). Upon optimization, the conditions converged to an adsorbent concentration of 200 mg/L, pH 5, PNA concentration of 10 mg/L, and a contact duration of 22.5 min, under which an impressive PNA adsorption efficacy of 98.6% was attained. Kinetic and isotherm analyses insinuated the adsorption mechanism to adhere predominantly to the pseudo-second-order kinetic and Langmuir isotherm models. The magnetic nanocomposite was recovered and used in 4 cycles, and the absorption rate reached 86%, which shows the good stability of the magnetic nanocomposite in wastewater treatment. Conclusively, these empirical outcomes underscore the viability of the formulated magnetic nanobiocomposite as a potent, recyclable adsorbent for the proficient extraction of PNA from aqueous matrices.

Facile and green synthesis of recyclable, environmentally friendly, chemically stable, and cost-effective magnetic nanohybrid adsorbent for tetracycline adsorption

Antibiotic contamination of water sources, particularly tetracycline (TC) contamination, has emerged as one of the global issues that needs action. In this research, ZnCoFe2O4@Chitosan (Ch) as a magnetic nanohybrid adsorbent was synthesized using the microwave-assisted co-precipitation method, and their efficiency for the TC adsorption process was investigated. FESEM (Field Emission Scanning Electron Microscope), EDX (Energy Dispersive X-ray), Mapping and line Scan, XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Spectrometer), VSM (Vibrating Sample Magnetometer), Thermogravimetric analysis (TGA) and BET (Brunauer Emmett Teller) techniques were used to check and verify its physical and chemical properties. The removal of TC via the adsorption process from synthetic and real wastewater samples was investigated. The factors determining the TC adsorption process, comprising tetracycline concentration (5-30 mg/L), adsorbent dosage (0.7-2 g/L), contact time (2-45 min), and pH (3-11), were evaluated. The removal effectiveness for the synthetic sample and the real wastewater sample was 93 % and 80 %, respectively, under the ideal TC adsorption process parameters of pH 3, adsorbent dosage 1 g/L, TC initial concentration 5 mg/L, and contact time 30 min. According to kinetic and equilibrium studies, the adsorption of TC by ZnCoFe2O4@Ch follows pseudo-second-order kinetics and the Freundlich isotherm. Additionally, it was determined through the analysis of thermodynamic data that the process of exothermic adsorption is spontaneous and is followed by a decrease in disorder (ΔH = -15.16 kJ/mol, ΔS = -28.69 kJ/mol, and ΔG = -6.62 kJ/mol). After five cycles of recovery and regeneration, the ZnCoFe2O4@Ch magnetic nanocomposite was able to remove 65 % of the TC pollutant and had good chemical stability. The results showed that the magnetic nano-adsorbent ZnCoFe2O4@Ch is a novel magnetic nano-adsorbent with high adsorption capacity that can be utilized to eliminate pharmaceutical contaminants from aqueous solutions.

Nanoporous carbons based on coordinate organic polymers as an efficient and eco-friendly nano-sorbent for adsorption of phenol from wastewater

The major part of water pollutants includes of organic such as phenolic pollutant, thus there are every hazardous to environment. Present work is a comparative onto surface chemistry and adsorptive characteristics of coordinate organic polymer (Cop-150) and nanoporous carbon (NPC) prepared using solvothermal method. New NPC was successfully synthesized to remove of phenol. FT-IR, XRD, XPS, SEM, TGA, and BET techniques have been used to characterization and confirm physicochemical variation during preparing Cop-150 and NPC. Box-Behnken response surface methodology (BBRSM) was used to optimize four important factors of the pH (2-10), contact time (1-40 min), temperature (25-60 °C), and initial concentration of phenol (5-50 mg L-1). To analyze the data obtained from the adsorption of phenol by synthesized adsorbents, four linear, 2FI, quadratic and cubic models were examined, which the quadratic model was recognized as the best model. To the NPC the equal adsorption capacity 500 mg g-1 is achieved at the initial concentration of phenol = 49.252 mg L-1, contact time = 15.738 min, temperature = 28.3 °C, and pH 7.042. On the other hand, the adsorption capacity for Cop-150 in pH 4.638, the contact time = 19.695 min, the temperature = 56.8 °C, and the initial concentration of phenol = 6.902 mg L-1 was equal to 50 mg g-1. The experimental data at different conditions were investigated by some famous kinetic and isotherm models, which among them, were corresponded to the pseudo-second-order kinetic model and the Langmuir isotherm. Moreover, based to result of thermodynamics to the both Cop-150 and NPC, the adsorption process is exothermic and spontaneous. According to results the Cop-150 and NPC could be used for up to four and five cycles without significantly reducing their performance, respectively.

Heterogeneous Sono-Fenton like catalytic degradation of metronidazole by Fe3O4@HZSM-5 magnetite nanocomposite

In this research, Fe₃O₄@HZSM-5 magnetic nanocomposite was synthesized via a coprecipitation method for metronidazole (MNZ) degradation from aqueous solutions under ultrasonic irradiation which showed superb sonocatalytic activity. The synthesized magnetite nanocomposite was characterized by using field-emission scanning electron microscope-energy dispersive X-ray Spectroscopy, (FESEM-EDS), Line Scan, Dot Mapping, X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). To investigate the sonocatalytic activity of the Fe₃O₄@HZSM-5 magnetite nanocomposite, the sonocatalytic removal conditions were optimized by evaluating the influences of operating parameters like the dosage of catalyst, reaction time, pH, the concentration of H₂O₂, MNZ concentration, and pH on the MNZ removal. The MNZ maximum removal efficiency and TOC at reaction time 40 min, catalyst dose 0.4 g/L, H₂O₂ concentration 1 mM, MNZ initial concentration 25 mg/L, and pH 7 were achieved at 98% and 81%, respectively. Additionally, the MNZ removal efficiency in the real wastewater sample under optimal conditions was obtained at 83%. The achieved results showed that using Langmuir-Hinshelwood kinetic model K_L-H = 0.40 L mg^-1, K_C = 1.38 mg/L min) can describe the kinetic removal of the process. The radical scavenger tests indicated that the major reactive oxygen species were formed by hydroxyl radicals in the Sono-Fenton-like process. Evaluation of the nanocomposite reusability showed an 85% reduction in the MNZ removal efficiency after seven cycles. Based on the results, it can be concluded that Fe₃O₄@HZSM-5 were synthesized as magnetic heterogeneous nano-catalysts to effectively degrade MNZ, and the observed stability and recyclability demonstrated that Fe₃O₄@HZSM-5 was promising for the treatment of wastewater contaminated with antibiotics.

Enhanced activation of persulfate by CuCoFe2O4@MC/AC as a novel nanomagnetic heterogeneous catalyst with ultrasonic for metronidazole degradation

In this study, the degradation of Metronidazole (MNZ) using CuCoFe₂O₄@MC/AC catalyst synthesized by microwave-assisted method, as an efficient activator for persulfate (PS) in the presence of ultrasonic (US: 60 kHz) was investigated. X-ray powder diffraction (XRD), Field emission scanning electron microscope (FESEM), Energy dispersive spectroscopy (EDS)-Mapping and Line scan, Fourier transform infrared spectroscopy (FTIR), Vibrating-sample magnetometer (VSM), and Thermal gravimetric analysis (TGA) were conducted to characterize the structure of CuCoFe₂O₄@MC/AC catalyst and then the catalyst dose, PS dose, MNZ concentration, and pH parameters were optimized. The maximum MNZ degradation of 93.78 % was achieved after 15 min reaction at the optimized operation conditions: 0.4 g L^-1 of catalyst, 6 mM of PS, 5 mg L^-1 of MNZ, and pH of 3. The removal efficiency of Total Organic Carbon (TOC) was 87.5 % under optimal conditions. According to kinetic equations, it was found that the MNZ degradation followed both kinetics (pseudo-first-order and Langmuir-Hinshelwood) based on the coefficient of determination (R²) of 0.949, 0.9716, 0.9073, 0.9721, and 0.9662 at concentrations of 5, 10, 15, 20, and 30, respectively. The surface reaction rate constant (K_c) and the adsorption equilibrium constant (K_L-H) of the Langmuir-Hinshelwood model were 0.81 (mg L^-1 min^-1) and 2.184 (L mg^-1), respectively. The free radical scavenging experiments were conducted to illustration the proposed mechanism, which shown that the SO₄^-• was the predominant radicals involved in MNZ degradation. Finally, the regeneration of the catalyst was investigated and showed that after five cycles of use and regeneration by chemical and thermal methods, this catalyst has acceptable chemical stability.

Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

A comparative study on the performance of photo/sono/peroxone processes for the removal and mineralization of reactive dye red 198 from aquatic environments

Colored wastewater is the most important problem of textile manufacturing factories, because it contains pollutants with complex structure and toxic, carcinogenic, and mutagenic properties which are non-biodegradable and sustainable in the environment. Reactive Red 198 (RR198) is one of the types of azo dyes which are widely used in the textile industries. Therefore, in this study, the rate of degradation and mineralization of RR198 by UV/US/H2O2/O3 hybrid process was investigated. Influencing factors including: initial dye concentration (100, 200, 300, 400, 500 mg/L), contact time (12.5, 30, 47.5, 65, 82.5 min), pH (3, 5, 7, 9, 11), UV (125-W), H2O2 (10, 20, 30, 40, 50 mg/L), US (160 KHz) and O3 (33 mg/(L·min)) on the removal and mineralization efficiency of RR198 were investigated. Optimization and modeling of the process was done by CCD method. Based on the results of ANOVA analysis, most effective parameters on the RR198 removal efficiency were ozone, US, UV, time, initial dye concentration, pH, and H2O2, respectively, with an impact percentage of 96.86 and less than 1% for ozone and the rest parameters, respectively. Highest removal efficiency of RR198 was obtained by UV/US/H2O2/O3 hybrid process. Optimal conditions for dye removal including: initial dye concentration of 200 mg/L, reaction time of 34 min, H2O2 concentration of 27 mg/L and pH of seven were determined in the presence of ozone gas, UV, and US waves. In these conditions, the removal efficiency of RR198 and TOC were estimated to be 100 and 40.5, respectively. UV/US/H2O2/O3 hybrid process as an advanced oxidation process (AOP) with advantages such as high performance and speed, no sludge production and toxic residues in the treated effluent containing hard biodegradable compounds such as RR198 from aqueous solutions, so can be recommended and used.

Hybrid UV/COP advanced oxidation process using ZnO as a catalyst immobilized on a stone surface for degradation of acid red 18 dye

Azo dyes are the largest group of synthetic organic dyes which containing the linkage C-N[bond, double bond]N-C and used in various industries such as textile industries leather articles, and some foods. Azo dyes are resistant compounds against the biodegradation processes. The purpose of this research was hybrid UV/COP advanced oxidation process using ZnO as a catalyst immobilized on a stone surface for degradation of acid red 18 (AR18) Dye. In the hybrid process using some parameters such as the dye initial concentration, pH, contact time and catalyst concentration, the process efficiency was investigated. In order to the dye removal, the sole ozonation process (SOP), catalytic ozonation process (COP) and photocatalytic process (UV/ZnO) were used. The ZnO nanoparticles were characterized by XRD, SEM and TEM analyses.  The maximum dye removal was achieved 97% at the dye initial concentration 25 mg/L, catalyst concentration 3 g/L, contact time 40 min and pH 5. As a real sample, the Yazdbaf textile factory wastewater was selected. After that, the physicochemical quality was evaluated. As well as, in the optimal conditions, the AR18 dye removal efficiency was achieved 65%. The kinetic results demonstrated that the degradation reaction was fitted by pseudo-first-order kinetic. The UV/COP hybrid process had high efficiency for removal of resistant dyes from the textile wastewater. Advantages of this technique were as follows:•ZnO nanoparticles were synthesized as catalyst by thermal method and were immobilized on the stones.•pH changes had no significant effect on the removal efficiency.•In the kinetic studies, the decomposition reaction followed pseudo-first order kinetic.

Synthesis of Fe3O4 nanoparticles @Trioctylmethylammonium thiosalicylat (TOMATS) as a new magnetic nanoadsorbent for adsorption of ciprofloxacin in aqueous solution

The aim of this research was to investigate ciprofloxacin (CIP) removal efficiency from aqueous solutions by using Fe3O4 nanoparticles @Trioctylmethylammonium thiosalicylat Ionic liquid (Fe3O4 NP@ TOMATS IL) as a new magnetic nanoadsorbent. The adsorbent was characterized by field emission scanning electron microscope-energy dispersive spectroscopy (FESEM-EDS), mapping, Fourier transform infrared spectroscopy (FT-IR), the Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD). The effects of solution pH, adsorbent dose, contact time, initial CIP concentration, and temperature on CIP removal were also investigated. In optimal conditions such as pH = 5.6, CIP concentration = 30 mg/L, adsorbent dose = 0.15 g, temperature = 30 °C, contact time = 90 min, the removal efficiency in synthetic and real wastewater were obtained 87 and 73%, respectively. Batch experiments were carried out to study the sorption Kinetics, thermodynamics, and equilibrium isotherms of CIP with magnetic nanoadsorbent. The results show that all of the above factors influence CIP removal. The Langmuir adsorption isotherm fits the adsorption process well, with the pseudo second-order model describing the adsorption kinetics accurately. The thermodynamic parameters indicate that adsorption is mainly physical adsorption. Recycling experiments revealed that the behavior of adsorbent is maintained after recycling for four times.