Synthesis of New Modified with Rhodamine B Peptides for Antiviral Protection of Textile Materials.

Here we report on the synthesis and characterization of three new N-modified analogues of hemorphin-4 with rhodamine B. Modified with chloroacetyl, chloride cotton fabric has been dyed and color coordinates of the obtained textile materials were determined. Antiviral and virucidal activities of both the peptide-rhodamine B compounds and the dyed textile material were studied. Basic physicochemical properties (acid-base behavior, solvent influence, kinetics) related to the elucidation of structural activity of the new modified peptides based on their steric open/closed ring effect were studied. The obtained results lead to the conclusion that in protic solvent with change in pH of the environment, direct control over the dyeing of textiles can be achieved. Both the new hybrid peptide compounds and the modification of functionalized textile materials with these bioactive hemorphins showed virucidal activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5) for different time intervals (30 and 60 min) and the most active compound was Rh-3.

A facile synthesis of graphene oxide/locust bean gum hybrid aerogel for water purification.

Graphene oxide/locust bean gum (GO/LBG) aerogels, synthesized in an ice crystal template without using any chemical modifiers, were used for the treatment of water pollution. Various characterization results showed that GO/LBG aerogel exhibited a network-like three-dimensional (3D) structure with large specific surface area. The adsorption data revealed that GO/LBG aerogels with GO/LBG mass ratio of 1:4 (GO/LBG-1 aerogels) exhibited more prominent adsorption properties for Rhodamine-B (RhB, 514.5 mgg-1) than Indigo Carmine (IC, 134.6 mgg-1). Simultaneously, GO/LBG-1 aerogels could selectively remove RhB from a binary mixed solution of RhB-IC dyes. Furthermore, GO/LBG-1 aerogels also displayed excellent reusability and could still reach 92.4 % after ten cycles. Based on the above results, GO/LBG-1 aerogel could be considered as an ideal adsorbent with potential application value for removing water-soluble RhB from wastewater.

Adsorption onto MWCNTs Coupled with Cloud Point Extraction for Dye Removal from Aqueous Solutions: Optimization by Experimental Design.

AIMS: The main aim of the study was to examine the feasibility and benefits of adsorption onto multi-walled carbon nanotubes (MWCNTs) coupled with cloud point extraction (CPE) for the removal of Rhodamine B (RB) from aqueous solutions. BACKGROUND: MWCNTs offer the particular features of the ideal adsorbents for the organic dyes such as hollow tubular structure and specific surface area. Nevertheless, they suffer from the drawbacks of low dispersion in the aqueous solutions and separation inconvenience from the media. Cloud point extraction, combined with the adsorption onto MWCNTs can be a promising method to overcome the problems. OBJECTIVE: In the study, adsorption onto MWCNTs coupled with CPE was applied for RB removal from aqueous solutions. The process was optimized by the response surface modeling method. Moreover, the applicability of the proposed method in the real sample analyses was investigated. METHODS: MWCNTs were used as adsorbent and Triton X-100 (TX-100) as the nonionic surfactant for CPE process. The experiments were carried out based on a Box-Behnken design (BBD) with the input variables of MWCNTs dosage (0.6-1.2 mg), solution pH (3-9), clouding time (20-40 min) and TX-100 concentration (10-20 v/v%) using 5 mg L-1 RB solutions. RESULT: Regression analyses resulted in a statistically significant quadratic model (R2=0.9718, F=24.96, p<0.0001) by which the optimum levels of the variables were predicted as: MWCNTs dosage of 0.7 mg, pH=3, clouding time of 39.9 minutes and TX-100 concentration of 19.91% (v/v). The predicted conditions were experimentally validated by achieving an RB removal of 94.24%. CONCLUSION: Based on the results, the combination of the environmentally friendly technique of CPE with adsorption onto MWCNTs allows the efficient removal of RB from water samples and the method can be effectively optimized by the response surface modeling.

Removal of Zwitterionic Rhodamine B Using Foam Separation.

Foam separation promotes the removal of dissolved materials from solutions by adsorbing the molecules onto a surfactant. The zwitterion of rhodamine B was removed by using both anionic (sodium dodecyl sulfate: SDS) and cationic (dodecyltrimethylammonium chloride: DTAC) surfactants through foam separation. However, rhodamine B could not be removed from a strongly acidic DTAC solution (pH 2), because the molecular form changes from the zwitterion to cation. Moreover, the cationic dye of rhodamine 6G could not be removed from the DTAC solution. Therefore, these results demonstrate that the electrostatic interaction between a surfactant and target ion is an important factor in foam separation.

Graphene-like BN@SiO2 nanocomposites as efficient sorbents for solid-phase extraction of Rhodamine B and Rhodamine 6G from food samples.

A novel dendritic silicon dioxide nanocomposite coated with a highly dispersed graphene-like boron nitride nanosheet (g-BN(x)@SiO2) was in-situ synthesized and employed as a solid-phase extraction material for the Rhodamine B (RhB) and Rhodamine 6G (R6G) enrichment in food samples prior to their quantitation by HPLC. The structures and morphologies of g-BN(x)@SiO2 were characterized by XRD, FTIR, BET and TEM. The adsorption performance and mechanism were investigated and showed an enhanced maximum adsorption capacity of 625 mg/g for RhB on the nanocomposite loaded with 1% of g-BN via a fast, spontaneous process. Under optimal extraction conditions, this method showed low detection and quantification limits (2.8 µg/L for RhB, 2.1 µg/L for R6G and 9.2 µg/L for RhB, 6.9 µg/L for R6G, respectively), good repeatability (RSD% <3.7%), and satisfactory spiked recoveries of 94.8%-103.1% for RhB and R6G in real chili powder and beverage. Therefore, the g-BN(1%)@SiO2-based materials possess significant potential.

Synthesis of Fe2SiO4-Fe7Co3 Nanocomposite Dispersed in the Mesoporous SBA-15: Application as Magnetically Separable Adsorbent.

The mixture containing alloy and oxide with iron-based phases has shown interesting properties compared to the isolated species and the synergy between the phases has shown positive effect on dye adsorption. This paper describes the synthesis of Fe2SiO4-Fe7Co3-based nanocomposite dispersed in Santa Barbara Amorphous (SBA)-15 and its application in dye adsorption followed by magnetic separation. Thus, it was studied the variation of reduction temperature and amount of hydrogen used in synthesis and the effect of these parameters on the physicochemical properties of the iron and cobalt based oxide/alloy mixture, as well as the methylene blue adsorption capacity. The XRD and Mössbauer results, along with the temperature-programmed reduction (TPR) profiles, confirmed the formation of Fe2SiO4-Fe7Co3-based nanocomposites. Low-angle XRD, N2 isotherms, and TEM images show the formation of the SBA-15 based mesoporous support with a high surface area (640 m2/g). Adsorption tests confirmed that the material reduced at 700 °C using 2% of H2 presented the highest adsorption capacity (49 mg/g). The nanocomposites can be easily separated from the dispersion by applying an external magnetic field. The interaction between the dye and the nanocomposite occurs mainly by π-π interactions and the mixture of the Fe2SiO4 and Fe7Co3 leads to a synergistic effect, which favor the adsorption.

Efficient removal of toxic organic dyes and photoelectrochemical properties of iron-doped zirconia nanoparticles.

Iron (Fe)-doped ZrO2 tetragonal nanoparticles were synthesized by a facile and inexpensive hydrothermal technique, that were doped with Fe3+ ions (0.1, 0.3, and 0.5 mol%) into the host lattice without altering the morphology and crystal structure of the nanoparticles. SEM and TEM investigations indicated that the morphology of ZrO2 nanoparticles did not change even after incorporation of Fe, while the band gap of semiconducting ZrO2 nanoparticles was reduced from 4.97 to 1.77 eV. Such a in band gap was responsible to harvest more photons to stimulate the generation of more electrons in the valence band, thereby enhancing the photoelectrochemical (PEC) water splitting as well as photocatalytic and photoelectrocatalytic activities in the photodegradation of Rhodamine B. The 0.3 mol%-doped ZrO2 electrode showed enhanced photocurrent density (0.07 × 10-3 A/cm2), that was 45-times greater than the pure sample. The electrochemical impedance spectroscopy (EIS) confirmed that 0.3 mol%-doped ZrO2 exhibited the best charge transfer characteristics, which increased with PEC water splitting activity. The maximum photocurrent density and long-term photo-stability were achieved in the light on-off states.

Magnetite nanoparticle embedded Pectin-graft-poly(N-hydroxyethylacrylamide) hydrogel: Evaluation as adsorbent for dyes and heavy metal ions from waste water.

A pectin (Pec) based gel has been made by grafting N-hydroxyethylacrylamide (HEAA) on pectin using potassium peroxodisulphate as initiator and N,N-methylenebisacrylamide as crosslinker under microwave irradiation. The magnetite (Fe3O4) nanoparticles were incorporated within this gel via in situ diffusion of Fe2+ and Fe3+ followed by reaction with ammonia solution. The synthesized gel, pectin-graft-poly(N-hydroxyethylacrylamide) (Pec-g-PHEAA); and the magnetite containing composite (Pec-g-PHEAA/Fe3O4) were characterized by FTIR, TGA, XRD, BET and SEM techniques. The magnetic property measurement indicated ferromagnetic nature of the nanocomposite. The Pec-g-PHEAA and Pec-g-PHEAA/Fe3O4 systems were evaluated for removal of dye and metal ions from aqueous solution using Rhodamine 6G (R6G), a cationic dye; Cu(II) and Hg(II) ions. Both adsorbents showed significant adsorption capacity towards these species, with greater adsorption capacity in case of Pec-g-PHEAA/Fe3O4. Adsorption process is observed to follow both Langmuir and Freundlich isotherm models for R6G dye and Freundlich isotherm model for Cu(II) and Hg(II) ions. The adsorption was found to be a pseudo first order process for R6G and pseudo second order process for Cu(II) and Hg(II) ions. The positive values of ∆H0 and the negative values of ∆G0 indicated the adsorption process to be endothermic and spontaneous.

Integration of plasmonic effect into MIL-125-NH2: An ultra-efficient photocatalyst for simultaneous removal of ternary system pollutants.

Industrial effluents often contain mixed metal ions and dyes, and it is difficult to efficiently remove both types of contaminants simultaneously. Here, MIL-125-NH2@Ag/AgCl composites were for the first time developed through a facile deposition-photoreduction method for simultaneously removing Cr(VI)/Rhodamine B (RhB)/Malachite Green (MG) ternary system pollutants under visible-light irradiation. The capacities of Cr(VI) reduction dramatically increased to 98.4% in the coexistence of RhB and MG compared to that of binary (Cr(VI)/RhB (69.6%) or Cr(VI)/MG (67.5%)) and single Cr(VI) (29%) systems. In the meantime, the degradation efficiencies of dyes especially RhB in the ternary system were also improved compared to that of their individual systems. On the grounds of all the experimental results, it can be concluded that the efficient light-harvesting and electrons migration in MIL-125-NH2@Ag/AgCl and the synergistic effect of redox reactions between Cr(VI) and dyes hinder the recombination of photo-induced electron-hole pairs, which are responsible for their high photocatalytic activity to eliminate the mixed pollutants. This study provides a new route to construct high-performance photocatalysts for the practical treatment of wastewater containing mixed pollutants.

In Situ Synthesis of MIL-100(Fe) at the Surface of Fe3O4@AC as Highly Efficient Dye Adsorbing Nanocomposite.

A new magnetic nanocomposite called MIL-100(Fe) @Fe3O4@AC was synthesized by the hydrothermal method as a stable adsorbent for the removal of Rhodamine B (RhB) dye from aqueous medium. In this work, in order to increase the carbon uptake capacity, magnetic carbon was first synthesized and then the Fe3O4 was used as the iron (III) supplier to synthesize MIL-100(Fe). The size of these nanocomposite is about 30-50 nm. Compared with activated charcoal (AC) and magnetic activated charcoal (Fe3O4@AC) nanoparticles, the surface area of MIL-100(Fe) @Fe3O4@AC were eminently increased while the magnetic property of this adsorbent was decreased. The surface area of AC, Fe3O4@AC, and MIL-100(Fe) @Fe3O4@AC was 121, 351, and 620 m2/g, respectively. The magnetic and thermal property, chemical structure, and morphology of the MIL-100(Fe) @Fe3O4@AC were considered by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Brunner-Emmet-Teller (BET), and transmission electron microscopy (TEM) analyses. The relatively high adsorption capacity was obtained at about 769.23 mg/g compared to other adsorbents to eliminate RhB dye from the aqueous solution within 40 min. Studies of adsorption kinetics and isotherms showed that RhB adsorption conformed the Langmuir isotherm model and the pseudo second-order kinetic model. Thermodynamic amounts depicted that the RhB adsorption was spontaneous and exothermic process. In addition, the obtained nanocomposite exhibited good reusability after several cycles. All experimental results showed that MIL-100(Fe) @Fe3O4@AC could be a prospective sorbent for the treatment of dye wastewater.

Mutual effects behind the simultaneous removal of toxic metals and cationic dyes by interlayer-expanded MoS2 nanosheets.

Simultaneous removal of coexisting metals and dyes from industrial wastewaters is challenging, and the mutual effects behind the co-adsorption of these pollutants remain unclear. Herein, interlayer-expanded MoS2 (IE-MoS2) nanosheets prepared by a one-pot simple and scalable method were tested to simultaneously remove toxic metals and cationic dyes. The adsorption capacities of IE-MoS2 nanosheets were 499, 423, 500, 355, and 276 mg/g for Pb(II), Cu(II), methylene blue, malachite green, and rhodamine B, respectively, in a mono-contaminant system. Interestingly, the sequestration amount of Pb(II) was dependent on the concentrations of dyes in the binary Pb(II)-dye systems, while uptake of cationic dyes was almost not influenced by coexisting Pb(II). The simultaneous adsorption mechanism was further confirmed by spectroscopic methods. The IE-MoS2 nanosheets were easily regenerated and reused for six adsorption-desorption cycles without structure destruction, thus avoiding the potential hazards of nanomaterial to the ecosphere. More interestingly, high-efficiency uptake of Pb(II) from intentionally contaminated natural water and model textile effluent was obtained by using a column filled with IE-MoS2 nanosheets. In summary, IE-MoS2 nanosheets with facile and scalable synthesis method, efficient adsorption performance, and excellent reusability showed potential promise for the integrative treatment of complex wastewater bearing both metals and organic pollutants.

Synthesis of chitosan based molecularly imprinted polymer for pipette-tip solid phase extraction of Rhodamine B from chili powder samples.

The purpose work is devoted to design of a simple, one-pot and green approach for the synthesis of molecularly imprinted polymer to construct a selective sorbent for pipette-tip solid phase extraction of Rhodamine B from chili powder samples and its subsequence separation and quantification by high performance liquid chromatography-ultraviolet/visible detection. The prepared molecularly imprinted polymer was synthesized using chitosan as versatile natural multi-functional bio-monomer and Rhodamine B as template in aqueous media. The effects of influential parameters (sorbent dosage, flow rate and eluent solvent volume) and their influences on Rhodamine B extraction recovery were examined and optimized by central composite design based response surface methodology as a powerful multivariate optimization tool. Under the optimized conditions, the linear range and limit of detection and quantification of proposed method were achieved to be 0.005-15 mg kg-1, 0.0015 mg kg-1 and 0.00488 mg kg-1, respectively, with satisfactory recoveries (>85.0%) and excellent repeatability (relative standard deviation < 6.1%). The easy synthesis conditions as well as satisfactory figures of merit are good indication of applicability of suggested method for extraction and determination of Rhodamine B from chili powder samples in terms of simplicity, cost effectiveness, selectivity and accurate analysis.

Multiple nitrogen functionalized magnetic nanoparticles as an efficient adsorbent: synthesis, kinetics, isotherm and thermodynamic studies for the removal of rhodamine B from aqueous solution.

The continuous demand for clean and affordable water needed for the survival of man is now a major challenge globally. Therefore, the treatment of wastewater generated from printing, textile and dyeing industries containing soluble dyes like rhodamine B (Rh-B) is of utmost important. This study investigates the efficiency of new multifunctionalized superparamagnetic nanoparticles (MNP-Tppy) for the removal of cationic Rh-B from aqueous solution. To afford MNP-Tppy, the surface of MNP was covalently functionalized with terpyridine ligand to enable an anionic charge on the adsorbent. The results of characterization including Brunauer-Emmett-Teller (BET) analysis, thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), scanning electron microscope (SEM) and fourier transform infra-red spectroscopy (FTIR) indicate that this superparamagnetic nanoparticle functionalized with multiple nitrogen atoms was successfully synthesized. Adsorption experiments involving the effect of pH, time, temperature, adsorbent dose and adsorbate concentration show that the maximum adsorption of Rh-B using MNP-Tppy was observed at pH 9 and removal was observed to increase as solution pH increases. Similarly, time variation shows that adsorbate removal increases as adsorption time increases until the removal attained equilibrium at 15 min. Kinetic studies conducted among four kinetic models using the data obtained from effect of time indicate that the adsorption process can best be described by the pseudo-second order model. Isotherm studies conducted at three different temperatures revealed that Langmuir isotherm model fitted well for the equilibrium data with qm value of 113.64 mg g-1 and thermodynamic studies showed that the adsorption process involving the removal of Rh-B from aqueous solution by MNP-Tppy is spontaneous, endothermic and realistic in nature. Lastly, Reusability experiments indicate that MNP-Tppy can be regenerated and re-used.

Magnetic mesoporous polyimide composite for efficient extraction of Rhodamine B in food samples.

A core-shell structured magnetic polyimide composite has been synthesized by the covalent coating of a mesoporous polyimide polymer onto the surface of magnetite nanoparticles. The nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption isotherms, X-ray diffraction, infrared spectroscopy, and vibrating sample magnetometry. The results showed that the prepared composite had a large surface area (306.45 m²/g), a unique pore size (2.15 nm), and strong magnetic properties (45.7 emµ/g), rendering it a promising sorbent material for magnetic solid-phase extraction. The parameters that affect the extraction efficiency of rhodamine B were optimized with the assistance of response surface methodology. Under the optimal conditions, the developed method has been successfully applied to determine the rhodamine B in food samples. The linearities and limits of detection of rhodamine B in hot pepper, red wine, and chili powder samples were measured. Satisfactory recoveries in the range of 94.8-103.3% with relative standard deviations <5.5% were obtained. Investigation of the adsorption mechanism of magnetic polyimide composite indicated that multiple interactions, including hydrophobic, π-π, and hydrogen bonding interactions, were involved in the adsorption process.

A simple solvent extraction and ultra-performance liquid chromatography-tandem mass spectrometric method for the identification and quantification of rhodamine B in commercial lip balm samples.

Rhodamine B is a synthetic dye used in many industries including cosmetics. Long-term contact may results neurotoxicity, genotoxicity and cancer. In the present work, a simple solvent extraction followed by rapid, sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometric method has been proposed for the identification and quantification of rhodamine B in lip balm samples for the first time to our knowledge. The best extraction was achieved using organic solvent n-hexane followed by sonication, centrifugation and evaporation. The chromatographic separation was attained in <1 min with Acquity™ BEH C18 reversed phase column and a tandem mass spectrometer. The limit of detection (LOD), limit of quantification (LOQ), linearity, precisions and accuracy of the proposed method were determined. The LOD and LOQ were found to be 0.1 µg/kg and 0.4 µg/kg, respectively. The linearity (R2) was obtained (>0.999) when analyzing low to higher range of concentrations. The precisions with relative standard deviation (RSD%) values in terms of repeatability (<2%, n = 5) and reproducibility (<3%, n = 5) were achieved. The accuracy in terms of recovery was obtained between 93% and 98%. The optimized procedures have been applied for the identification and quantification of rhodamine B in commercial lip balm samples from various brands and origin, and the amounts were obtained from not detected to 70.44 µg/kg. The good quality conditions, negligible matrix influence and higher recovery values obtained throughout analysis have proved the suitability of the present method for the routine analysis of rhodamine B in lip balm samples. The achieved results could be used to approximate the application of rhodamine B from individuals either from Saudi Arabia or globally, and thus to improve the quality and safety of lip balm products.

Synthesis of nitrogen-doped carbon nanotubes-FePO4 composite from phosphate residue and its application as effective Fenton-like catalyst for dye degradation.

Phosphate residue is regarded as a hazardous waste, which could potentially create significant environmental and health problems if it is not properly treated and disposed of. In this study, nitrogen-doped carbon nanotubes-FePO4 (NCNTs-FePO4) composite was successfully synthesized from phosphate residue, and its application as an effective catalyst was explored. Firstly, an effective method was developed to recover FePO4 from phosphate residue, achieving an impressive FePO4 mass recovery rate of 98.14%. Then, the NCNTs-FePO4 catalyst was synthesized from the recovered FePO4 by two main reactions, including surface modification and chemical vapor deposition. Finally, the synthesized NCNTs-FePO4 was applied to photo-degrade 15 mg/L Rhodamine B (RhB) in a Fenton-like system. The results showed that 98.9% of RhB could be degraded in 60 min, closely following the pseudo-first-order kinetics model. It was found that even after six consecutive cycles, NCNTs-FePO4 still retained a high catalytic capacity (>50%). Moreover, •OH radicals participating in the RhB degradation process were evidenced using quenching experiments and electron paramagnetic resonance analysis, and a rational mechanism was proposed. It was demonstrated that the materials synthesized from hazardous phosphate residue can be used as an effective catalyst for dye removal.

A novel environmental-friendly nanobiocomposite synthesis by EDTA and chitosan functionalized magnetic graphene oxide for high removal of Rhodamine B: Adsorption mechanism and separation property.

The synergistic combination of two different environmentally friendly functional groups (EDTA and Chitosan) with magnetic graphene oxide (mGO) nano-sheets was used for synthesizing a promising nanobiocomposite adsorbent (CS-EDTA-mGO) for efficient removal of a cationic dye, Rhodamine B (RhB), from aqueous solutions. CS-EDTA-mGO nanobiocomposite was characterized by XRD, FTIR, VSM, TGA, and zeta potential. Further, the morphological features of the synthesized graphene oxide and mGO were examined by SEM technique. The adsorption conditions were designed and optimized by experimental design applied by faced-central composite design. CS-EDTA-mGO indicated high sorption capacity where the R% of 92% was obtained under optimal conditions (sorbent dosage = 0.14 g L-1; dye concentration = 114 mg L-1; pH = 7.5; temperature = 33 °C). The result of kinetics studies revealed that the adsorption was considerably fast and the data followed the pseudo-second-order kinetic model. The adsorption equilibrium of the cationic dye by CS-EDTA-mGO showed that the Langmuir model fitted the experimental data significantly and the maximum adsorption capacity estimated from Langmuir model was 1085.3 mg g-1, which was highly consistent with the maximum experimental adsorption capacity. The thermodynamic parameters represented that the interaction in the adsorption process was endothermic and the randomness at the solid/solution interface increased during the process. Both physical and chemical mechanisms were involved in the adsorption process, owing to the complicated structural characteristics of the nanobiocomposite. After seven cycles of adsorption/desorption, the removal efficiency of CS-EDTA-mGO nanobiocomposite was still over 80% with little loss of adsorption capacity (≈2%).

Activation of peroxymonosulfate by Fe-N complexes embedded within SBA-15 for removal of organic contaminants via production of singlet oxygen.

Persulfates are recognized as promising oxidants and an alternative to Fenton reaction for water treatment. However, activation methods in hand restrict the practical application. Herein, we explore the possibility of Fe-N complexes being a catalyst for persulfate activation for the first time. The catalyst denoted as Fe-Im-SBA was synthesized from ferric chloride, imidazole, and SBA-15 at high temperature. The internal pore structure of Fe-Im-SBA was maintained well; Fe, N and C elements are evenly distributed on the catalyst. This catalyst presents an extraordinarily catalytic activity for Rh B removal by PMS activation with a removal rate of Rh B that reached up to 97.0% in the first 5 min. It also performed well in a wide pH range with complete removal of Rh B in pH ranged from 0.5 to 10, suggesting the stability of this catalyst in both acidic and alkaline conditions. It also showed high adaptability to degrade different kinds of pollutants, which could give an attractive advantage of Fe-Im-SBA for environmental implications. Through X-ray absorption spectroscopies analysis, it shows that the active sites of Fe-Im-SBA are composed of Fe-N4 sites and Fe2-N2 sites. 1O2 were proved to generate in the Fe-Im-SBA/PMS system and serve as the major ROS. Meanwhile, graphitic carbon can accelerate the transfer of electrons, which may also be the reason for its high catalytic performance.

Iron impregnated biochars as heterogeneous Fenton catalyst for the degradation of acid red 1 dye.

In the present work, Acid Red 1 (AR1) dye degradation by two heterogeneous Fenton catalysts, namely iron loaded rice husk biochar (Fe-RHB) and coir pith biochar (Fe-CPB) are studied. Biochar prepared from RHB and CPB were sonicated in the presence of ferric nitrate for the synthesis of Fe-RHB and Fe-CPB by incipient impregnation method. Effect of operational parameters such as pH, the dosage of catalyst, H2O2 concentration and temperature were examined. Characterization of the synthesized Fenton catalyst, Fe-RHB and Fe-CPB were analysed by SEM, EDS, XRD and XPS techniques. In Fe-RHB Fenton system, maximum dye removal efficiency of 97.6% and TOC removal efficiency of 84.2% were obtained at pH 3 for 50 mg L-1 of AR1 concentration, with 16 mM of H2O2 and 5 g L-1 of catalyst dosage within 120 min reaction time. Similarly, for Fe-CPB, maximum dye removal efficiency of 99.1% and TOC removal efficiency of 86.7% were obtained with 16 mM of H2O2 and 4 g L-1 of dosage for 50 mg L-1 of initial dye concentration at pH 3. The prepared catalysts can be reused for successive cycles as the catalyst materials are highly stable and have very less iron leaching property.

Synthesis of zinc ferrite/silver iodide composite with enhanced photocatalytic antibacterial and pollutant degradation ability.

ZnFe2O4/AgI composites were first prepared successfully with a hydrothermal method, and ZnFe2O4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe2O4/AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe2O4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe2O4/AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80 min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40 min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe2O4/AgI composites. In addition, H2O2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe2O4/AgI composites are a promising candidate for the treatment of wastewater.