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Industrial effluent-containing dyes are the main cause of contamination in waterways. In the current research, green waste-mediated ferrites, i.e., Ni-FNPs, Mn-FNPs, Co-FNPs, Cu-FNPs, and Zn-FNPs, were amalgamated and presented through Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The optimum pH for the adsorption of reactive turquoise blue 21 dye was 3 (45.41 mg/g), 3 (43.26 mg/g), 3 (41.45 mg/g), 4 (37.71 mg/g), and 4 (34.79 mg/g), respectively, for Ni-FNPs, Mn-FNPs, Co-FNPs, Cu-FNPs, and Zn-FNPs with a biosorbent dose of 0.05 g/50 mL and commencing dye concentration was 50 mg/L. Reactive turquoise blue 21 dye biosorption capacities were 44.97, 41.82, 37.61, 33.83, and 28.39 mg/g for Ni- FNPs, Mn-FNPs, Co-FNPs, Cu-FNPs, and Zn-FNPs respectively, when measured at 60, 60, 45, 45, and 60 min contact time,respectively. Also, the initial dye concentration, effect of biosorbent dose and temperature on reactive turquoise blue 21 dye were thoroughly investigated. The reaction was exothermic, as evidenced by the decrease in sorption capacity that was seen as the temperature was elevated. While the pseudo-second-order demonstrated good fitness on the kinetic data of experiments, the Langmuir equilibrium isotherm demonstrated good accuracy on the data collected by sorption. Surfactants, detergents, and various molar solutions of electrolytes (NaCl, CaSO4, and CuSO4) reduced sorbent sorption capacity for reactive turquoise blue 21 dye. Thus, the goal of the current investigation was to eliminate reactive turquoise blue 21 dye and prove that these green waste-mediated ferrites might be reliably prepared and applied to ensure the successful eradication of reactive turquoise blue 21 dye from hydrophilic solution in column and batch modes.

ABSTRACT

This study is focused on the synthesis of a solar light driven novel poly(vinyl alcohol) (PVA)-assisted TiO2/Ti film via a facile one pot hydrothermal technique and then its photocatalytic applications by adding with peroxymonosulfate (PMS) for efficient degradation of ciprofloxacin (CIP). The key hydrothermal synthesis parameters like PVA-content, hydrothermal time (HT), and pH were optimized. The best photocatalytic performance of the synthesized material was observed when prepared with the conditions of PVA = 8 mg, HT= 3 h, and pH = 2.62. Results showed that 98.3% of CIP was degraded within 60 min by PVA-assisted TiO2/Ti film with 0.5 mM PMS added, compared to 89.38% and 88.86% degradation with 0.5 mM persulfate (PS) and 0.5 mM hydrogen peroxide (H2O2), respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added was dependent on the [PMS]0and increased with increase in [PMS]0. The kappvalues at [PMS]0of 0.2, 0.5, 0.8, and 1.0 mM were 0.029, 0.0582, 0.068, and 0.128 min–1, respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation was highly dependent on the [pH]0as well as on the presence of coexisting anions like HCO3–, CO32–, NO2–, Cl–, and SO42–. Natural organic matter (NOM) retarded the photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation due to its strong scavenging ability toward •OH and SO4•–. The photocatalytic degradation of CIP by as-prepared photocatalyst under solar light irradiation was higher in Milli-Q water (kapp= 0.0582 min–1) than tap water (kapp= 0.0342 min–1) followed by river water (kapp= 0.0259 min–1) and then synthetic wastewater (kapp= 0.0212 min–1). The degradation products of CIP were investigated by UPLC-MS/MS, and accordingly degradation pathways were proposed. Moreover, the mineralization, ecotoxicity, and cyclic photocatalytic stability of the as-prepared photocatalyst were also investigated. These findings suggest that as-prepared PVA-assisted TiO2/Ti film with PMS added is a promising alternative for the treatment of wastewater containing antibiotics.

One of the most significant environmental problems facing the entire planet today is water contamination, which is caused by the increasing industry and urbanization. The present study involves the synthesis of polymeric ferrite composites Ni-CoFe2O4/Chitosan, Zn-NiFe2O4/Starch, Co-NiZnFe2O4/Polyaniline, Ni doped CrZnFe2O4/Alginate, and Cr doped ZnCoFe2O4/PVA for the removal of Golden Yellow-160 dye. The polymeric ferrite composites were characterized using Scanning electron microscopy (SEM), X-ray Diffraction (XRD), and Fourier transmission infrared spectroscopy (FT-IR) which showed the surface morphology, crystallinity, chemical structure and thermal stability of the composites. To get the optimal removal, different parameters like pH, composite dose, contact time, temperature and initial dye concentration were optimized. Different equilibrium and kinetic models were used to check the nature of process and reaction rate of sorption. Thermodynamic were studied to check the feasibility of reaction. The effect of presence of various electrolytes NaCl, CaCl2.2H2O and AlCl3.6H2O was also studied. Effect of presence of different metals and surfactants was also studied which cause reduction in adsorption of dyes. For large scale, the effects of bed height, flow rate, and initial dye concentration were examined in column study. Different eluents were used for the desorption study of reactive dyes to check the reusability of process.

Objective: This study aimed to explore bereaved parents’ and healthcare providers experiences of care after stillbirth. Study design: Qualitative in-depth interviews with 55 women, men, female elders, healthcare providers and key informants in Kabul province, Afghanistan between October and November 2017. Results: Inadequate and insensitive communication and practices by healthcare providers, including avoiding or delaying disclosing the stillbirth were recurring concerns. There was a disconnect between parents’ desires and healthcare provider’s perceptions. The absence of shared decision-making on seeing and holding the baby and memory-making, manifested as profound regret. Health providers’ reported hospitals were not equipped to separate women who had a stillbirth and acknowledged that psychological support would be beneficial. However, the absence of trained personnel and resource constraints prevented provision of such support. Conclusion: Findings can inform future provision of perinatal bereavement care. Given resource constraints, communication training can be considered with longer term goals to develop context-appropriate bereavement care guidelines.

Nitrogen-doped titanium dioxide (N-TiO2) nanoparticles were prepared using a modified sol-gel method. The as-prepared nanoparticles were characterized by state-of-the-art techniques for their optical, structural and morphological properties. The crystallite size, surface area and bandgap energy of reference TiO2and N-TiO2nanoparticles were found to be 16.1 and 10.9 nm, 83.6 and 131.8 m2g−1and 3.23 and 2.89 eV, respectively. The photocatalytic activities, in terms of 2,4-dichlorophenol (2,4-DCP) degradation, of reference TiO2and N-TiO2were found to be 46.9% and 65.4% at 120 min of treatments under UV light irradiation and 21.5% and 77.6% at 240 min of treatment under visible light irradiation, employing 153.4 µM 2,4-DCP, 1 g/L photocatalyst dosage, and pH 5.6. Interestingly, considerable H2production rate (i.e., 386 μmol h−1g−1) was observed for visible/N-TiO2system in presence of 0.2 wt% Pt. The study revealed that visible/N-TiO2photocatalytic system can be used as an economically viable technology for environmental sustainability.

In this study, for the first-time, aqueous solution of Acid Fuchsin (AF) was spectrophotometrically evaluated as a possible chemical dosimeter for food irradiation dosimetry at low dose ranges. A 50 µM solution of AF at natural pH was gamma irradiated and absorbance of the solution was measured at λmax(i.e., 543 nm) in addition to other wavelengths (490, 510, 549 and 564 nm). The response of AF dosimeter was investigated by plotting various variables, i.e., absorbance (A), − log A, change in absorbance (∆A), log Ao/Aiand absorbance % (A %) against absorbed dose. The response plots suggested that the beneficial dose range of AF solution in water was up to 0.82 kGy when absorbance (A), change in absorbance (ΔA) and absorbance % (A %) were extrapolated against absorbed dose. Though, the response was linear and beneficial absorbed dose range was extended up to 1.65 kGy, when − log A and log Ao/Aiwere plotted against absorbed dose. It was concluded from pre- and post-irradiation stability studies of AF dosimeter that it should be protected from light and heat during handling and storage. For detection of the reactive specie involved in the bleaching of AF dye the AF dye solution was saturated with O2, N2and N2O gases.

This study pertains to theoretical aspect of membrane and surfactant supported ultrafiltration technique followed by experimental evaluation of rejection percentage (R%) and permeate flux (J). The organic dye malachite green (MG) was removed from water samples with help of micellar solution of sodium dodecyl sulfate (SDS) surfactant on account of effective surfactant-dye interaction. The MG removal from water was result of electrostatic force of attraction between Stern layer of SDS micelles and cationic MG in addition to hydrophobic-hydrophobic interaction. The regenerated cellulose membrane was used to retain enhanced MG-SDS micellar complex from polluted water in stirred ultrafiltration cell. R% of MG increases from 79.3%, 77%, 76% to 97.5%, 95%, 90% for 0.01, 0.1 and 0.2 mM concentrations, respectively. “J” decreases throughout the experiment on account of membrane plugging or concentration polarization. Hydrodynamic radius (Rh) of SDS surfactant was also determined at its post micellar concentrations by dynamic laser light scattering (DLLS) that shows high rejection percentage with increased Rhvalues.

The oxidative degradation of CV dye in aqueous media has been evaluated using Fenton (Fe2+/H2O2) and photo-Fenton (Fe2+/H2O2/UV) processes. Various operational parameters like H2O2dosages, Fe2+dosages and [CV]0were optimized of both Fenton and photo-Fenton processes for the removal of CV dye from aqueous media. Kinetic results indicated that photo-Fenton process (kobs=0.0097 min−1, t1/2=71.45 min) is more effective than Fenton process (kobs=0.0074 min−1, t1/2=93.66 min). Second order rate constant of ˙OH radical with CV dye was calculated to be 3.96×109M−1s−1. De-methylated organic intermediates of CV dye detected by LC-MS and some other intermediates like CH3COO−, HCOO−, NH4+and Cl−were identified by ion-chromatography.

For the first time, chloroform and 2-butanol were used as solvent systems for the preparation of ZrO2–PANI and CeO2–PANI composites. Solubility of the synthesized composites was studied in chloroform, N-methyl-2-pyrrolidinone (NMP), and in mixture of toluene + 2-propanol (2:1). XRD and cyclic voltammetry data showed that the ZrO2–PANI and CeO2–PANI composites possess both crystalline and amorphous domains indicating some sort of conductivity. TGA results showed that ZrO2–PANI composite have a better thermal stability than pure PANI; however, CeO2–PANI composite has lower thermal stability than pure PANI. The conjugated unsaturated structure of PANI is responsible for the enhanced photocatalytic properties of ZrO2–PANI and CeO2–PANI. Photocatalytic results showed that, at photolysis time of 60 min, rhodamine B (RhB) dye was degraded up to 34 and 35% by ZrO2–PANI and CeO2–PANI, respectively. The degradation products of RhB were quantified by LC–MS and GC–MS, and accordingly, a detailed pathway was proposed.

Bronchobiliary fistula (BBF) is an abnormal connection between the bronchial system and biliary tree. It is a rare condition that often manifests as bilioptysis. BBF has several causes; however infectious disease of the liver and lungs, mostly hydatid cysts, is the leading cause of BBF. For a conclusive diagnosis, imaging studies are useful and able to show the fistula tract, as we did by CT scan. The treatment of BBF is still a challenge for surgeons. In children, in the acute fulminating phase, an aggressive and rapid approach is essential to prevent respiratory tract damage.

In the present research work the degradation of acid yellow 17 (AY 17) by H2O2/Fe2+was investigated. The effect of various conditions such as pH value, temperature, conc. of H2O2, Fe2+, conc. of AY 17 were studied. Additionally the scavenging effects of various anions such as Cl−, SO42−, CO32−and HCO3−, on percent degradation of AY 17 were examined. It was found that these anions decrease percent degradation as well as rate of degradation reaction. The optimum conditions were determined as [AY 17]=[Fe2+]=0.06 mM [H2O2]=0.9 mM, and pH 3.0 for 60 min of reaction time. It was found that at optimum conditions 89% degradation of AY17 was achieved. The degradation kinetics of AY17 followed pseudo-first-order reaction kinetics. Thermodynamic studies under natural conditions showed positive value of ∆H (enthalpy) which indicates the degradation process is endothermic.

Protonation plays an important role in the redox reactions. We observed this leading role during the reduction of [FeIII(phen)2(CN)2]+by FcCOMe and FcCHOHMe. The kinetic data showed that the reaction(s) followed a complex kinetics due to the formation of protonated acetylferrocene (FcC+OHMe), and or, protonated α-methylferrocenemethanol (FcCHO+H2Me) in aqueous dioxane (80% v/v). Our results helped us to conclude that the reactions were completed in three phases. An overall zeroth order was observed in the first phase of the reactions. In the second phase, the kinetic data showed an overall second order reaction. The third phase was a complex phase where the rate of redox reactions and the insolubility of the neutral product ([FeII(phen)2(CN)2]) competed with each other. We studied the effect of different factors to identify the reacting entities, which take part in the rate-determining step of each reaction in the second phase. Consequently, we determined the effects of selected factors upon the observed pseudo-first order rate constant(s) (k′obs) of each reaction. The value of k′obsincreased upon addition of protons in the reaction mixture in case of FcCOMe, and it decreased during the oxidation of FcCHOHMe. Meanwhile, upon enhancing the ionic strength, we observed an increase in k′obsfor FcCOMe, and no change in the value of k′obsduring the reaction of FcCHOHMe. However, a decrease in k′obswas noticed upon increasing the dielectric constant of the reaction mixture when the reductant was FcCOMe, and no effect was observed in case of FcCHOHMe. Together, these results suggested oxidation of FcC+OHMe and FcCHOHMe in the slow-step, and FcCOMe and FcCHO+H2Me during the fast-step. We refined our results by estimating the thermodynamic parameters of activation. The low values of activation energy and enthalpy of activation confirmed that the reduction of [FeIII(phen)2(CN)2]+hardly depends upon temperature when the reducing agent is FcCOMe. The outcomes justified that the rate of reaction depends upon the unsaturated FcC+OHMe. This intermediate species contain a ‘carbonium ion’, which is very reactive and energetic. We obtained comparatively high values of the activation energy and enthalpy of activation for the reaction between [FeIII(phen)2(CN)2]+and FcCHOHMe. The results show that FcCHOHMe is a saturated and stable compound that leads the slow-step and controls the rate of reaction.

Influence of temperature on production of pyrolysates from used tire rubber

In this work, we report the synthesis of composite system pNAC, composed of silver nanoparticles embedded in pure thermo-sensitive crosslinked polymer network of poly(N-isopropylacrylamide-co-acrylamide) (pNA), using as a catalyst for the reduction of methylene blue (MB) dye by sodium borohydride (NaBH4). The pNA was prepared by conventional free radical polymerization technique using sodium dodecyl sulfate as stabilizing agent, followed by in situ reduction of AgNO3inside the polymer network by NaBH4for the synthesis of composite systems pNACs. The synthesized pNA and pNACs were characterized by FTIR, dynamic light scattering, thermo-gravimetric analysis, scanning electron microscopy and UV–visible spectroscopy techniques. The materials were found sensitive toward temperature change of the medium. The entrapment ability of pNA toward different amounts of AgNO3solution was studied, and effect of metal content on particle size of pNACs was analyzed. The pNACs were applied as a catalyst for the reduction of MB in which they exhibit high catalytic activity and reusability toward the reaction.

Three dimensional cross-linked polymer microgels with temperature responsive N-isopropyl acrylamide (NIPAM) and pH sensitive methacrylic acid (MAA) were successfully synthesized by free radical emulsion polymerization with different amounts of MAA. Silver and gold nanoparticles with the size of 6.5 nm and 3.5 nm (±0.5 nm), respectively were homogeneously reduced inside these materials by chemical reduction method at pH 2.78 and 8.36 for the preparation of hybrid materials. The samples were characterized by FT-IR, DLS and TEM techniques. The catalytic activity of the hybrid materials was investigated for the reduction of 4-nitrophenol (4-NP) using NaBH4 as reducing agent by UV-Vis spectroscopy. The hybrid polymer network synthesized at pH 8.36 showed enhanced catalytic efficiency compared to the catalysts synthesized at pH 2.78. In this study, it has been stated that the catalyst activity strongly depends on the amount of MAA, pH value during synthesis and the type of entrapped metal nanoparticles.

Multiresponsive tercopolymer microgel poly(N-isopropyl acrylamide-co-methacrylic acid-co-2-hydroxyethyl methacrylate) was synthesized by free radical emulsion polymerization. The silver and gold nanoparticles were homogeneously dispersed in polymer network by in-situ chemical reduction method at 10 and 40°C using sodium borohydride as reducing agent. FT-IR spectroscopy confirms the microgel synthesis and existing of metal nanoparticles inside the polymer network. Temperature and pH sensitivity on particle size of the microgel particles was investigated by dynamic light scattering. Transmission electron microscopy analysis showed that the size of Ag and Au nanoparticles is 13 and 7nm, respectively. The catalytic activity of hybrid microgels was studied for the reduction of aqueous solutions of 4-nitrophenol, congo red and methylene blue as model reactions.

This study demonstrates the synthesis of highly hydrophilic poly(vinylidene fluoride) composite membranes incorporated with Titania (TiO2) nanotubes (PVDF/TNT) and then its photocatalytic applications were explored for effective degradation of brilliant green (BG) dye. The membranes were fabricated through phase inversion method using poly(vinylidene fluoride) (PVDF) as matrix, Titania nanotubes (TNT) with different concentrations (0–2 wt%) as filler and poly(vinylpyrrolidone) as pore former. Successful fabrication of composite membranes (PVDF/TNT) was confirmed by using X-ray diffraction analysis, Fourier transform infra-red spectroscopy, differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Membrane properties were studied using contact angle, tensile strength, solvent content, pure water flux, bovine serum albumin (BSA) rejection, antifouling properties, porosity and shrinkage ratio. The degradation results suggested that the fabricated membrane can effectively be applied as a heterogenous photocatalyst for the degradation of BG. The results confirm that the dispersion of TNTs increases the antifouling properties of membranes to a maximum value. A minimum pore volume 0.34 cc g−1, pore size 28.4 nm and maximum surface area 142 m2 g−1were obtained with loading 1.5 wt% TNTs in PVDF membranes, which can degrade BG up to 42% compared to 13% in the absence of fabricated membrane after 90 min of reaction time. The photocatalytic degradation mechanism of BG by PVDF/TNT ultrafiltration membranes showed that OH is mainly involved in the degradation process. The degradation byproducts of BG were determined using LC–MS/MS and accordingly degradation pathways were proposed.

The original article can be found online at https://doi.org/10.1007/s11696-017-0334-1.