Systematic optimization of biochars derived from corn wastes, pineapple leaf, and sugarcane bagasse for Cu(II) adsorption through response surface methodology.

Many industrial wastewaters contain an appreciable amount of toxic copper (Cu(II)) that needs to be properly treated before discharging into receiving water body. Adsorption can effectively remove Cu(II) with optimized parameters. This study investigates the critical pyrolysis parameters of biochar derived from agricultural waste. Optimized biochar showed maximum Cu(II) adsorption capacity of 60.7, 36.8, and 35.5 mg g-1 by PLB, SBB, and CWB at pyrolysis temperatures of 555 ℃, 559 ℃, 507 ℃, respectively, compared with commercial activated carbon (CAC, 40.8 mg g-1). Surface characterization confirmed surface complexation, electrostatic interaction, and cation exchange capacity as Cu(II) removal mechanisms. The presence of humic acid reduced the Cu(II) removal of both CAC and optimized biochars. Optimized PLB displayed high reusability (87% Cu(II) removal efficiency) after five consecutive cycles using pressure cooker regeneration. With excellent Cu(II) adsorption capacity and reusability, the investigated biochars show high applicability potential to Cu(II)-laden wastewater treatment.

Fabrication of Ternary Nanoparticles for Catalytic Ozonation to Treat Parabens: Mechanisms, Efficiency, and Effects on Ceratophyllum demersum L. and Eker Leiomyoma Tumor-3 Cells.

The use of parabens in personal care products can result in their leakage into water bodies, especially in public swimming pools with insufficient water treatment. We found that ferrite-based nanomaterials could catalytically enhance ozone efficiency through the production of reactive oxygen species. Our objective was to develop a catalytic ozonation system using ternary nanocomposites that could minimize the ozone supply while ensuring the treated water was acceptable for disposal into the environment. A ternary CuFe2O4/CuO/Fe2O3 nanocomposite (CF) delivered excellent degradation performance in catalytic ozonation systems for butylparaben (BP). By calcining with melamine, we obtained the CF/g-C3N4 (CFM) nanocomposite, which had excellent magnetic separation properties with slightly lower degradation efficiency than CF, due to possible self-agglomeration that reduced its electron capture ability. The presence of other constituent ions in synthetic wastewater and actual discharge water resulted in varying degradation rates due to the formation of secondary active radicals. 1O2 and •O2− were the main dominant reactive species for BP degradation, which originated from the O3 adsorption that occurs on the CF≡Cu(I)−OH and CF≡Fe(III)−OH surface, and from the reaction with •OH from indirect ozonation. Up to 50% of O3-treated water resulted in >80% ELT3 cell viability, the presence of well-adhered cells, and no effect on the young tip of Ceratophyllum demersum L. Overall, our results demonstrated that both materials could be potential catalysts for ozonation because of their excellent degrading performance and, consequently, their non-toxic by-products.

Insights to the 3D internal morphology and metal oxidation states of single atmospheric aerosol particles by synchrotron-based methodology.

The morphology and metal oxidation states of atmospheric aerosols are pertinent to their formation processes and ensuing interactions with surrounding gases, vapors and other environments upon deposition, such as human respiratory tract, soil and water. Although much progress has been made in recent years through single-particle techniques, considerably less is known with respect to the three-dimensional (3D) internal morphology of single atmospheric aerosol particles due to the limited penetration depth of electron microscopy. In this study, for the first time, a novel synchrotron-based transmission X-ray microscopy (TXM) methodology has been developed to visualize the 3D internal chemical mixing state and structure of single particles. The results show that the TXM is more applicable to the imaging of solid particles containing high-density elements, e.g., iron (Fe), aluminum (Al), silicone (Si), carbon (C) and sulfur (S), and/or solid particles of sizes larger than about 100 nm. In addition, the TXM is capable to reveal the fine 3D topographic features of single particles. The derived 3D internal and external information would be difficult to discern in the 2D images from electron microscopy. The TXM 3D images illustrate that aerosol particles exhibit complex internal mixing state and structure, e.g., homogeneously-, heterogeneously-mixed, multiple inclusions, fibrous, porous, and core-shell configuration. When coupled with the synchrotron-based X-ray fluorescence spectrometry (XRF) and absorption near-edge spectroscopy (XANES) of an X-ray nanoprobe in the energy range of 4-15 keV, the 3D morphology of single particles is further supplemented with the spatial distribution and oxidation sates of selected elements, including Fe, vanadium (V), manganese (Mn), chromium (Cr) and arsenic (As). The presented cross-platform, synchrotron-based methodology shows promise in complementing existing single-particle techniques and providing new insights to the heterogeneity of single-particle micro-physicochemical states relevant to the aerosol chemistry, optical properties, and their environmental and health impacts.

Novel biomass-derived porous-graphitic carbon coated iron oxide nanocomposite as an efficient electrocatalyst for the sensitive detection of rutin (vitamin P) in food and environmental samples.

Design and development of inexpensive, portable, and eco-friendly electrochemical non-enzymatic sensors with high selectivity and sensitivity is pivotal in analytical chemistry. In this regard, we have developed a highly porous graphitic-activated carbon (GAC, derived from tamarind fruit shell biomass) coated iron oxide (Fe2O3) nanocomposite (Fe2O3/GAC) for the efficient detection of rutin (vitamin p). Fe2O3/GAC nanocomposite was prepared using a facile green synthesis method and thoroughly characterized using SEM, XRD, and XPS techniques. As-prepared Fe2O3/GAC nanocomposite was deposited over a screen printed electrode (SPE) to fabricate Fe2O3/GAC/SPE and utilized as a non-enzymatic sensor for the electrochemical determination of rutin in food and environmental samples. The modified electrode was characterized using cyclic voltammetry and electrochemical impedance spectroscopy techniques, which witnessed the excellent conductivity of the developed sensor. The fabricated Fe2O3/GAC/SPE nanocomposite exhibited a set of redox peaks in the presence of rutin, corresponding to the electrochemical redox feature of rutin (rutin to 3',4'-diquinone). Further, the modified electrode displayed excellent electrocatalytic characteristics towards the oxidation of rutin, based on which a differential pulse voltammetry-based sensor was developed for rutin determination. The developed non-enzymatic sensor has shown prominent performance towards rutin detection in a wide linear range from 0.1 to 130 µM with an excellent detection limit of 0.027 µM. The enhanced electrocatalytic response could be ascribed to the synergistic effect of Fe2O3 and GAC on the developed probe. Moreover, the developed sensor was successfully utilized for real-time detection of rutin in various samples.

Adsorption of metal on pineapple leaf biochar: Key affecting factors, mechanism identification, and regeneration evaluation.

Although tremendous works have been done on metal adsorption via biochar, mechanisms responsible for metal adsorption remain uncertain. This is the first work that provides direct evidence on the identification of Ni(II), Zn(II), and Cu(II) adsorption mechanisms on pineapple leaf biochar (PLB) using surface characteristics analyses, including X-ray photoelectron spectroscope (XPS), Fourier transform infrared spectroscope (FTIR), and scanning electron microscope with energy-dispersive X-ray spectroscope (SEM-EDS). From Langmuir isotherm fitting, the maximum adsorption capacity of PLB for Ni(II), Zn(II), and Cu(II) are 44.88, 46.00, and 53.14 mg g-1, respectively, surpassing all biochars reported in the literature. Findings of surface characterization techniques coupled with cation released during adsorption, cation exchange, and surface complexation mechanisms were proposed. PLB is reusable and remains sufficient adsorption capacity even six consecutive cycles via pressure cooker regeneration. With high regenerability and ultrahigh adsorption capacity, PLB defines itself as a promising adsorbent for future applications in metal-laden wastewater.

Doping TiO2 with CuSO4 enhances visible light photocatalytic activity for organic pollutant degradation.

Photocatalysis is one of the most promising advanced oxidation processes due to the capability of solid catalyst to continuously produce oxidant species under light irradiation. The use of conventional UV lamps is high cost intensive, which undermines the possible implementation in developing countries. Visible light active photocatalysts can overcome these challenges and find a market opportunity for competitive technology implementation. This work proposes the synthesis of visible light active catalyst following a facile sol-gel synthesis that introduces CuSO4 as dopant in TiO2. Results present complete abatement of methylene blue in 120 min of treatment under 50 mW cm-2 of blue light (λ = 450 nm), while commercial P25 TiO2 presented null abatement under identical conditions. Synthesis parameters including dopant level and calcination temperature allowed defining optimum synthesis conditions based on material characteristics modification and catalytic activity enhancement. A doping level of 0.21 mol% CuSO4 was identified as optimum condition to enable visible light photocatalysis of doped TiO2 catalysts calcined at 300 °C. Finally, operational parameters were evaluated defining a wide range of pH operation under 3.0 g L-1 of catalyst dose to treat up to 20 g L-1 of highly recalcitrant phenothiazine dye. These optimum conditions allowed complete dye removal under visible light after 120 min of treatment.

Kinetic study and performance comparison of TiO2-mediated visible-light-responsive photocatalysts for the inactivation of Aspergillus niger.

Fungi are highly survived with exceptional resistance to environmental stress. Conventional fungicides are quite efficient, but the increase in use raises severe environmental problems. In this study, environmentally friendly TiO2-mediated visible-light-responsive photocatalysts, namely N-TiO2, N-T-TiO2, C-TiO2, and Pd-C-TiO2, were used to compare the performance of disinfecting a mold fungi Aspergillus niger. Key parameters, including photocatalyst dosage, the initial fungal concentration, and visible-light intensity, affecting the disinfecting process, was investigated. A new developed Light-responsive Modified Hom's (LMH) kinetic model incorporating visible-light intensity and photocatalyst light-absorption coefficient was firstly used to predict such photocatalytic process in fungal inactivation. Among the photocatalysts, Pd-C-TiO2 showed the highest inactivation performance against fungi, followed by C-TiO2, N-T-TiO2, and N-TiO2. In general, inactivation increased with increasing photocatalyst dosage and light intensity while decreased with increasing initial fungal concentration. For kinetic modeling, the LMH model supports the hypothesis that photocatalyst performance toward visible-light-driven fungal inactivation primarily depends on the light-absorption capacity of the photocatalyst. In conclusion, mold fungi Aspergillus niger are effectively disinfected by TiO2-mediated visible-light-responsive photocatalysts, and such fungal inactivation process could be predicted by LMH kinetic model.

Application of palladium-modified zeolite for prolonging post-harvest shelf life of banana.

BACKGROUND: The marketability of banana is limited by the rapid rate of ripening. However, the traditional post-harvest technologies may not be desirable. The aim of this study was to investigate the potential of a reusable material for the food preservation industry. RESULTS: The nanocomposite-based palladium (Pd)-modified zeolite (Pd/zeolite) was prepared by impregnating Pd into zeolite. Pd/zeolite had a Brunauer-Emmett-Teller dinitrogen specific surface area of 475 m2 g-1 with crystal structure similar to Y-zeolite. Transmission electron microscopy images showed the dispersion of Pd particles over the multi-pore zeolite support. Pd/zeolite uniquely acted as an adsorbent and a catalyst and was able to remove ethylene even after reaching breakthrough point. To prove Pd/zeolite is reusable, a 99 ± 0.8% ethylene removal efficiency still remained even after five consecutive cycles with repeated use of Pd/zeolite. The presence of Pd/zeolite significantly decreased the ethylene concentration during 18 days of storage at 20 ± 2 °C. CONCLUSIONS: Pd/zeolite could delay the ripening of banana and improve its firmness and the peel color significantly. Findings indicated that the as-prepared Pd/zeolite is an effective adsorbent/catalyst with high potential for practical application in ethylene removal, especially for the post-harvest period. © 2019 Society of Chemical Industry.

Effective degradation of primary color direct azo dyes using Fe0 aggregates-activated persulfate process.

The present study examined the oxidation power of a Fe0 aggregates/persulfate (PS/Fe0) system for the degradation of the wastewater containing mixed primary direct dyes (i.e., Sirius® Gelb S-2G, Sirius® Red F3B, and Sirius® Turkis GL01). Results indicated that decolorization efficiency was determined by operating parameters of the PS/Fe0 system and the structural complexity of dye molecules. System efficiency increased with increasing persulfate and Fe0 dosages. Faster decolorization was observed in experiments conducted at pH < 10. The process obeyed a first-order kinetics. Slow heterogeneous reactions were observed at high initial pH (>10.5) and low PS concentration (<2 × 10-3 M). Inhibitory effect occurred in systems containing salts Na2SO4, NaCl, Na2CO3, and Na2HPO4 at 1 × 10-2 M. The effect was suppressed when reaction temperature was raised to 55 °C. Heat enhanced not only decolorization efficiency, but also COD removal. Complete decolorization of a mixed dye containing ADMI (the American Dye Manufacture Institute) 15105 was achieved within10 min in the PS/Fe0/55 °C system with an initial pH of 6.0 and dosages of 5 × 10-3 M Na2S2O8 and 0.5 g/L Fe0. Low molecular weight intermediates including organic acids were identified. Due to a relatively low activation energy (4.68 kcaL/mol), the PS/Fe0 system exhibited higher efficiency at higher temperature. This study demonstrated that Fe0-activated PS is a promising process for the treatment of textile wastewaters containing mixed azo direct dyes.

Hyperspectral sensing for turbid water quality monitoring in freshwater rivers: Empirical relationship between reflectance and turbidity and total solids.

Total suspended solid (TSS) is an important water quality parameter. This study was conducted to test the feasibility of the band combination of hyperspectral sensing for inland turbid water monitoring in Taiwan. The field spectral reflectance in the Wu river basin of Taiwan was measured with a spectroradiometer; the water samples were collected from the different sites of the Wu river basin and some water quality parameters were analyzed on the sites (in situ) as well as brought to the laboratory for further analysis. To obtain the data set for this study, 160 in situ sample observations were carried out during campaigns from August to December, 2005. The water quality results were correlated with the reflectivity to determine the spectral characteristics and their relationship with turbidity and TSS. Furthermore, multiple-regression (MR) and artificial neural network (ANN) were used to model the transformation function between TSS concentration and turbidity levels of stream water, and the radiance measured by the spectroradiometer. The value of the turbidity and TSS correlation coefficient was 0.766, which implies that turbidity is significantly related to TSS in the Wu river basin. The results indicated that TSS and turbidity are positively correlated in a significant way across the entire spectrum, when TSS concentration and turbidity levels were under 800 mg·L(-1) and 600 NTU, respectively. Optimal wavelengths for the measurements of TSS and turbidity are found in the 700 and 900 nm range, respectively. Based on the results, better accuracy was obtained only when the ranges of turbidity and TSS concentration were less than 800 mg·L(-1) and less than 600 NTU, respectively and used rather than using whole dataset (R(2) = 0.93 versus 0.88 for turbidity and R(2) = 0.83 versus 0.58 for TSS). On the other hand, the ANN approach can improve the TSS retrieval using MR. The accuracy of TSS estimation applying ANN (R(2) = 0.66) was better than with the MR approach (R(2) = 0.58), as expected due to the nonlinear nature of the transformation model.

Functional annotation of proteomic data from chicken heterophils and macrophages induced by carbon nanotube exposure.

With the expanding applications of carbon nanotubes (CNT) in biomedicine and agriculture, questions about the toxicity and biocompatibility of CNT in humans and domestic animals are becoming matters of serious concern. This study used proteomic methods to profile gene expression in chicken macrophages and heterophils in response to CNT exposure. Two-dimensional gel electrophoresis identified 12 proteins in macrophages and 15 in heterophils, with differential expression patterns in response to CNT co-incubation (0, 1, 10, and 100 µg/mL of CNT for 6 h) (p < 0.05). Gene ontology analysis showed that most of the differentially expressed proteins are associated with protein interactions, cellular metabolic processes, and cell mobility, suggesting activation of innate immune functions. Western blot analysis with heat shock protein 70, high mobility group protein, and peptidylprolyl isomerase A confirmed the alterations of the profiled proteins. The functional annotations were further confirmed by effective cell migration, promoted interleukin-1ß secretion, and more cell death in both macrophages and heterophils exposed to CNT (p < 0.05). In conclusion, results of this study suggest that CNT exposure affects protein expression, leading to activation of macrophages and heterophils, resulting in altered cytoskeleton remodeling, cell migration, and cytokine production, and thereby mediates tissue immune responses.

Decolourization of direct blue 15 by Fenton/ultrasonic process using a zero-valent iron aggregate catalyst.

Decolourization of direct azo dye, direct blue 15 (DB15), by an advanced Fenton process coupled with ultrasonic irradiation (Fenton/US) was investigated. Zero-valent iron (ZVI) aggregates were used as the catalyst. A positive synergistic effect occurred when Fenton's reagent was combined with ultrasonic irradiation. Experimental results showed that the optimum conditions for decolourization were pH 3.0, Fe(0) 1g/L, H(2)O(2) 5.15×10(-3)mol/L with ultrasound density of 120W/L at 60kHz. These conditions yielded 99% decolouration of 4.7×10(-5) M DB15 (4130 ADMI) solution within 10min. DB15 decolouration follows the first-order decolouration kinetics. Although the solutions containing H(2)CO(3), Cl(-), ClO(4)(-), NO(3)(-) and SO(4)(2-) ions did not have a significant effect on the decolouration, the H(2)PO(4)(-) ion did decrease the decolouration rate. High ultrasonic input power accelerated the reaction and increased decolourization efficiency. The cost effectiveness of this process at high ultrasound density could be controlled despite the high electricity costs incurred by the process. ZVI aggregates were reusable; however, an increase in the number of times ZVI was recycled decreased the decolourization rate. This study demonstrates that a Fenton/US process can effectively decolour the direct azo dye DB15 in wastewater.

Magnetic Fe3O4 nanoparticles for adsorptive removal of acid dye (new coccine) from aqueous solutions.

The ability of magnetic Fe3O4 nanoparticles (MFN) to remove new coccine (NC), an acidic dye, from aqueous solutions was studied. Parameters including ionic strength, pH, and temperature were evaluated. MFN, prepared by precipitation method, exhibits an average particle size of 12.5 nm, specific surface area of 85.5 m²/g, and pH(zpc) of 5.9. Results of kinetic adsorption experiments indicated that the pseudo-second-order rate of adsorption increased with increasing initial NC concentration. Findings also revealed that the equilibrium data could be fitted into Langmuir adsorption isotherm. The adsorption is favored at low pH, high temperature, and low ionic strength, whereupon a maximum adsorption capacity of 1.11 x 10⁻4 mol/g was determined for NC. Thermodynamic functions indicated that the adsorption process is spontaneous and exothermic in nature. Tests of regeneration showed that after 5 regeneration cycles the adsorption capacity of NC decreased to 35% to its original capacity.

Removal of methylene blue from aqueous solution by adsorption onto pineapple leaf powder.

The ability of an unconventional bio-adsorbent, pineapple leaf powder (PLP) for the adsorption of methylene blue (MB) from aqueous solution was studied. It was observed that intra-particle diffusion was involved in the adsorption process and that the kinetic data fitted well with a pseudo-second-order equation. Fitting parameters revealed that the rate of adsorption increased with decrease in dye concentration and decrease in ionic strength while the mixing speed did not have a significant effect on adsorption. The adsorption was favorable at higher pH and lower temperature, and the equilibrium data were well fitted by the Langmuir isotherm. The maximum adsorption capacity varied from 4.68 x 10(-4) to 9.28 x 10(-4)mol/g when pH increases from 3.5 to 9.5. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. The results revealed that this agricultural waste has potential to be used as an economical adsorbent for the removal of methylene blue from aqueous solution.

Schizandrin protects primary cultures of rat cortical cells from glutamate-induced excitotoxicity.

The neuroprotective effect of schizandrin on the glutamate (Glu)-induced neuronal excitotoxicity and its potential mechanisms were investigated using primary cultures of rat cortical cells. After exposure of primary cultures of rat cortical cells to 10 microM Glu for 24 h, cortical cell cultures exhibited remarkable apoptotic death. Pretreatment of the cortical cell cultures with schizandrin (10, 100 microM) for 2 h significantly protected cortical neurons against Glu-induced excitotoxicity. The neuroprotective activity of schizandrin was the most potent at the concentration of 100 microM. Schizandrin reduced apoptotic characteristics by DAPI staining in Glu-injured cortical cell cultures. In addition, schizandrin diminished the intracellular Ca2+ influx, inhibited the subsequent overproduction of nitric oxide (NO), reactive oxygen species (ROS), and cytochrome c, and preserved the mitochondrial membrane potential. Furthermore, schizandrin also increased the cellular level of glutathione (GSH) and inhibited the membrane lipid peroxidation malondialdehyde (MDA). As indicated by Western blotting, schizandrin attenuated the protein level changes of procaspase-9, caspase-9, and caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Taken together, these results suggest that schizandrin protected primary cultures of rat cortical cells against Glu-induced apoptosis through a mitochondria-mediated pathway and oxidative stress.

Ameliorating effect of emodin, a constitute of Polygonatum multiflorum, on cycloheximide-induced impairment of memory consolidation in rats.

The aim of the present study was intended to investigate the ameliorating effects of emodin on memory consolidation via cholinergic, serotonergic and GABAergic neuronal systems in rats. First, we evaluated the ameliorating effects of emodin on cycloheximide (CXM)-induced impairment of passive avoidance response in rats. Secondly, we clarified the role of cholinergic, serotonergic or GABAergic system on the ameliorating effect of emodin by using 5-HT1A receptor partial agonist, 5-HT2 receptor antagonist, GABAB agonist, GABAA antagonist and muscarinic receptor antagonist. Emodin protected the rat from CXM-induced memory consolidation impairment. The beneficial effect of emodin on CXM-induced memory consolidation impairment was amplified by 8-OH-DPAT (5-HT1A receptor partial agonist) and ritanserin (5-HT2 receptor antagonist), but reduced by scopolamine. These results suggested that the beneficial effect of emodin on CXM-induced memory consolidation impairment was amplified by serotonergic 5-HT1A-receptor partial agonist and 5-HT2 receptor antagonist but reduced by muscarinic receptor antagonist.

Enhancement of electrokinetic remediation of hyper-Cr(VI) contaminated clay by zero-valent iron.

This paper investigated the effectiveness of incorporating zero-valent iron (ZVI) into electrokinetic (EK) to remediate hyper-Cr(VI) contaminated clay (2497 mg/kg). A ZVI wall was installed in the center of the soil specimen and was filled with 1:1 (w/w) ratio of granular ZVI and sand. Results show that transport of H(+) is greatly retarded by the strong opposite migration of anionic chromate ions, whereupon a revered electroosmosis flow (EO) was resulted and alkaline zone across the specimen was developed promoting the release of Cr(VI) from the clay. Chromium removal was characterized by high Cr(VI) concentration occurred in the anolyte and the presence of Cr(III) precipitates in the catholyte. The Cr(VI) reduction efficiencies for the process without ZVI wall were 68.1 and 79.2% for 1 and 2V/cm, respectively. As ZVI wall was installed, the corresponding reduction efficiencies increased to 85.8 and 92.5%. The costs for energy and ZVI utilized in this process are US$ 41.0 and 57.5 per cubic meter for the system with electric gradient of 1 and 2V/cm, respectively. The role of ZVI wall effectively reducing Cr(VI) contamination and the operation simultaneous collection of Cr(VI) from the electrode reservoirs are two major advantages of this process.

Effects of luteolin on learning acquisition in rats: involvement of the central cholinergic system.

The study was conducted to investigate the ameliorating effects of luteolin on memory acquisition in rats. The effects of luteolin on scopolamine-induced impairment of passive avoidance response were evaluated primarily, as well as the role of the central nervous system through the use of central neurotoxins and central nervous antagonists. Luteolin was not reversed by scopolamine N-methylbromide (M-SCOP) but blocked the impairment of learning acquisition induced by cholinergic neurotoxin (ethylcholine aziridinium, AF64A) and muscarinic (scopolamine hydrobromide, SCOP) and nicotinic (mecamylamine, MECA) receptor antagonists. However, it did not block dopaminergic neurotoxin (6-hydroxydopamine, 6-OHDA)-induced and serotonergic neurotoxin (5,7-dihydroxytryptamine, 5,7-DHT)-induced impairments. From these results, we suggest that the attenuating effect of luteolin (10 mg/kg, i.p.) on the deficits of passive avoidance performance induced by SCOP may be related to the increases in the activities of central muscarinic and nicotinic receptors.