Detoxification of photo-catalytically treated 2-chlorophenol: optimization through response surface methodology

Greener approach to substitute chemical reduction clearing process for fabric dyed with Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL using indigenous resources

Fabric dyed with disperse dyes followed a reduction clearing process (RCP)/chemical clearing process (CCP) to remove the unfixed dye from the fabric. In the clearing process, unfixed dyes and chemicals are discharged into streams. To combat this issue, an environment friendly approaches is explored that is a biological clearing using indigenous fungal strains of white-rot fungi (Pleurotus ostreatus and Ganoderma lucidum). In this context, fabrics dyed with three disperse dyes (Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL) were considered. The fabric cleared with biological clearing process improved the quality of fabric versus chemically cleared fabric and among the tested strains, G. lucidum showed higher efficiency for color strength improvement. However, no significant difference in tensile and tear strength of all fabric samples was observed. The quality of effluents in clearing reduction process for three dyes was assessed and it was observed that water quality parameters including chemical oxygen demand (COD), total organic carbon (TOC), biological oxygen demand (BOD), total suspended solids (TSS), pH, dissolved oxygen (DO) and total dissolved solids (TDS) improved significantly and results revealed that the biological clearing approach can substitute chemical reduction clearing process for fabric dyed with dyes, which is greener and eco-friendly versus conventional processes to avoid unfixed dyes discharge in to water bodies.

Synthesis of Cu-doped MgO and its enhanced photocatalytic activity for the solar-driven degradation of disperse red F3BS with condition optimization

In the present study, Cu (2–12%) doped MgO was synthesized and characterized by SEM, XRD, EDX, and FTIR spectroscopy. The Cu concentration significantly affected the band gap and particle size, which ranged from 4.63 to 3.78 eV and from 27.2 to 79 nm, respectively. In addition, the photocatalytic activity (PCA) of Cu-doped MgO was monitored by the photocatalytic destruction of disperse red F3BS coralene dye, and four reaction variables such as dye concentration, catalyst dose, hydrogen peroxide concentration, and irradiation time, respectively, were optimized by response surface methodology (RSM). Dye degradation was significantly affected by these process variables, and a degradation rate of up to 93% was achieved under optimized conditions. The wastewater samples were also treated under optimized conditions and water quality variables, i.e., chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were significantly improved after treatment. Cu-doped MgO exhibited excellent PCA under the solar-light exposure for the degradation of disperse red F3BS dye, which can be employed for the treatment of dye-containing effluents.

Kinetic Study of Degradation of Basic Turquise Blue X-GB and Basic Blue X-GRRL using Advanced Oxidation Process

This study focuses on application of advanced oxidation (Photo-Fenton) processes to decolorize Basic Turquise Blue (BTB) X-GB 250% and Basic Blue (BB) X-GRRL 250% dyes. The percent decolorization was studied in terms of effect of variation in intensity of UV light at optimum conditions of all the parameters (pH = 3.0, H2O2 = 4.8 mM, FeSO4 = 1.6 mM, temperature = 50 °C, time = 80 min for BTB X-GB, and pH = 5.0, H2O2 = 5.6 mM, FeSO4 = 2.0 mM, temperature = 40 °C, time = 60 min for BB X-GRRL). Maximum decolorization was obtained at maximum intensity (15660 counts/min) of UV light as 96.17% for BTB X-GB and 88.48% for BB X-GRRL. First order, 2nd order and BMG kinetic models were used to analyze the data obtained for intensity of UV light. BMG model gives us the higher values of correlation coefficients for all data of both the dyes. The results have shown that Photo-Fenton oxidation process is the beneficial and effective for oxidation treatment of waste water effluents containing dyes as main pollutants.

Gamma Radiation and Hydrogen Peroxide Based Advanced Oxidation Process for the Degradation of Disperse Dye in Aqueous Medium

In view of promising efficiency of advanced oxidation process (AOP), gamma radiation in combination with H2O2 was employed for the degradation of disperse red 73 (DR73) dye. Cs-137 gamma radiation source was used for dye aqueous solution irradiation. The process variables such as pH (3–9), H2O2 concentration (0.3–0.9 mL), gamma radiation absorbed dose (1–20 kGy) and DR73 initial concentration (50–150 mg/L) were optimized for maximum degradation of dye. The efficiency of AOP was evaluated on the basis of dye degradation, water quality parameters and toxicity reduction. Degradation of DR73 was achieved 69% using gamma radiation absorbed dose of 20 kGy and at the same dose 96.3% degradation was achieved in the presence of 0.9 mL/L H2O2. The dye degradation found to be dependent on dye initial concentration and pH of the medium. The radiolytic progress of DR73 was monitored by Fourier transform infrared (FTIR) and UV-Visible spectroscopy. The chemical oxygen demand (COD) and biological oxygen demand (BOD) were reduced significantly in response of treatment of dye at optimum conditions of process variables. The toxicity of treated and un-treated dye solution was monitored by haemolytic and Ames assays. Results revealed that the toxicity of DR73 dye was also reduced significantly after treatment. Findings revealed that the gamma radiation based AOPs are promising and could possibly be used for the remediation of textile wastewater contains toxic dyes.

Green Synthesis of Metal Nanoparticles and their Applications in Different Fields: A Review

Nanotechnology is an art for application and handling of materials at very small scales i.e. 1–100 nm. The materials at this scale exhibit significantly different properties compared to same materials at larger scales. There are so many physical and chemical methods for the synthesis of nanoscale materials but the most appropriate are the ones that synthesize materials using green chemistry eco-friendly techniques. Recently, the collaboration between nanotechnology and biology has opened up new horizons of nanobiotechnology that integrates the use of biological materials in a number of biochemical and biophysical processes. This approach has significantly boosted up nanoparticles (NPs) production without employing harsh and toxic conditions and chemicals. This review is aimed to provide an outline of latest developments in synthesis of NPs through biotic entities and their potential applications.

UV/H2O2/Ferrioxalate Based Integrated Approach to Decolorize and Mineralize Reactive Blue Dye: Optimization Through Response Surface Methodology

The decolorization and mineralization of Reactive Blue 222 dye was studied using UV/H2O2/ferrioxalate approach in combination with Pleorotus ostreatus. The dye was decolorized by UV/H2O2/ferrioxalate based advanced oxidation process (AOP) at different levels of process variables dye concentration, catalyst dose, pH, reaction time and resultantly, 80% decolorization was achieved. Pleorotus ostreatus treatment enhanced the dye degradation up to 92% at optimum levels of pH, temperature, inoculum size, carbon and nitrogen sources at specific concentration. Response Surface Methodology (RSM) was employed for optimization under face-centered central composite design (CCD). Although both treatments were found efficient for the removal of dye, but on applying the integrated approach, 96% dye removal was obtained which led to complete degradation of the dye. FTIR analysis confirmed the degradation of dye into low mass compounds. The water quality assurance parameters were measured to assess the mineralization efficiency. A significant reduction in COD (94%) and TOC (92%) were found when dye was degraded integrated approach. A phytotoxicity analysis on Pisum sativum plant revealed the non-toxic behavior of metabolites produced. Results revealed that the integrated approach is highly promising for the decolorization and mineralization of the Reactive Blue 222 dye and is also extendable to treat the dye in textile wastewater.

Structural, Dielectric and Magnetic Studies of Perovskite [Gd1−xMxCrO3 (M = La, Co, Bi)] Nanoparticles: Photocatalytic Degradation of Dyes

Nanoparticles (NPs) of Gd1−xMxCrO3 (M = La, Co, Bi) were synthesized by microemulsion techniques, involving simultaneous single ion substitution philosophy. Structural, magnetic, dielectric properties, morphology, elemental analysis and distribution size of fabricated nano-crystalline were determined. The techniques employed for investigation are X-ray diffraction (XRD), vibrating sample magnetometer (VSM), dielectric measurement and scanning electron microscopy (SEM), energy dispersive X-ray (EDX), photoluminescence (PL) and atomic force microscopy (AFM), respectively. XRD pattern confirm that all the as-synthesized NPs have orthorhombic structure and successfully substituted of different metal ions into the regular crystal structure of GdCrO3. The lattice parameters X-ray density, bulk density, porosity and grain size were calculated from XRD pattern of Gd1−xMxCrO3 (M = La, Co, Bi) substituted and un-substituted GdCrO3. The magnetic hysteresis loop of fabricated product confirmed that the entire sample exhibits ferromagnetic behavior at room temperature. It was also found that the fabricated NPs show excellent photocatalytic activity (PCA) against Congo-red, about 78.24% after 55 min of incubation.

Lead Remediation Using Smart Materials. A Review

The nanoparticles have been prepared and employed as excellent adsorbents for the sequestration of heavy metal ions and hazardous impurities from the aqueous media. The surface morphological, textural and structural properties of nanoparticles have been modified, which are capable and potentially useful for the remediation of metal ions. Several metals (oxides, doped, nanocomposites of Fe, Ti, Zn, SiO2, SiC, Mo, Co, Ni, Zr, Mn, Si, S, Al, Cu, Ce, graphene, CNTs) were reported an efficient adsorbents for the removal of lead (Pb) ions from aqueous media and polluted water. The present review focuses on different kinds of nanoparticles such as metal oxides, carbon based and host supported employed for removal of Pb ions under varying experimental conditions such as pH, temperature, contact time and concentrations. The preparation strategies, physicochemical properties and adsorption are also discussed. Based on studies, it was found that the smart materials are affective adsorbents for the purification of wastewater containing Pb ions and could possibly extended for the remediation of other heavy metal ions.

Decolorization of Basic Turquise Blue X-GB and Basic Blue X-GRRL by the Fenton’s Process and its Kinetics

Textile industries use dyes to color their products and release waste water containing dyes, causing water pollution which is a serious problem for survival of human life on earth. The decolorization of basic turquise blue X-GB (BTB X-GB) 250% and basic blue X-GRRL (BB X GRRL) 250% dyes was examined by advanced (Fenton process) oxidation process. The effects of different parameters (initial dye concentration, pH, concentrations of hydrogen peroxide (H2O2) and reaction time) have been examined and optimum conditions were determined. It has been noted that percentage decolorization of both dyes (50 mg/L) increases with increase in concentration of H2O2. At optimum conditions (pH=3.0, H2O2=4.8 mM, temperature=50°C, time=80 min of BTB X-GB, and pH=5.0, H2O2=5.6 mM, temperature=40°C, time=60 min of BB X-GRRL) the decolorization obtained by Fenton process was 85.83% of BTB X-GB and 74.98% for BB X-GRRL. 1st order, 2nd order and BMG kinetic models were used to analyze the data. BMG model gives us the higher values of correlation coefficients for all data. Results showed that Fe2+/H2O2 are most effective for oxidation treatment of waste water effluents containing dyes as main pollutants.