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Non-road vehicles equipped with diesel engine could emit air pollutants. This study measured particulate matters (PM) and gaseous pollutants of the exhaust of the non-road vehicles (excavator, bulldozers) during idling and operating. The concentrations of TPM, PM10 and PM2.5 were 14-251, 12-181 and 10-163 mg/Nm3, respectively, for three on-road vehicles. The PM10 occupy 60-70％ of TPM, while PM2.5 occupy 80-90％ of PM10. The calculated emission factors were 0.64 - 0.94, 0.53 - 0.79 and 0.32 -0.49 g/bhp-hr for TPM, PM10 and PM2.5, respectively. Metallic elements of PM were analyzed in order to evaluate the carcinogenic and non-carcinogenic risk. The results showed that the emission of total metallic elements from the excavator and two bulldozers are 2.711 and 7.922-22.618 mg/m3, respectively, and the dominant components are Zn, Fe and Al. Total carcinogenic risk of Cd and Pb decreased from 0.094´10-6 to 0.013´10-6 by increasing the distances from three non-road vehicles and the non-carcinogenic risk of both Cd and Pb are lower than the limits (HQ=1), which is considered an acceptable risk.

A Fidas Frog sampler is used to collect ambient air pollutants with various particle sizes at the Taichung Science Park in Taichung, Taiwan. The relationship between particle size and total number ...

Rice husk is a bulky byproduct with a high silica content from rice milling. In this study, the application of an acid-catalyzed ionic liquid (IL) pretreatment was studied for processing rice husks with a rugged structure. The pretreatment conditions were 130°C for 30 min with 1.2 wt% HCl. The results of enzymatic hydrolysis demonstrated that cellulose conversion of HCl-BMIMCl-treated at 48 h was increased by 660.05%, 538.81%, and 376.55% compared with the untreated, HCl-treated, and BMIMCl-treated rice husks, respectively. Composition analysis demonstrated that most of the hemicellulose was removed in the acid-IL combined treatment. Moreover, scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared analyses indicated that the crystalline structure and outer silica layer of the rice husks were efficiently broken up. The results revealed that the HCl-catalyzed dissolution is highly favorable for the industrial application of rick husks in the production of fermentable sugar and high-purity silica.

The exploitation of lignocellulosic biomass (LB) such as sugar bagasse waste in biorefineries is the most cost-effective and favourable sustainable approach to producing essential platform chemicals, materials, and energy environmentally benignly. Herein, a microwave-mediated deep eutectic solvents (DESs)/dimethyl sulfoxide (DMSO) system for efficiently processing LB waste into platform chemicals was proposed thereof. Under optimized appropriate diverse parameters such as solvent varieties, catalyst dosage, DMSO addition, reaction time and temperature, the proposed catalytic system (i.e., microwave mediated DESs/DMSO system) has demonstrated significant yields of 5-hydroxymethylfurfural (5-HMF), furfural (FF) and levulinic acid (LevA) of 31.29 %, 28.38 % and 35.65 %, respectively. These favourable results were obtained at the reaction temperature of 140 °C for 40 min. The anticipated catalytic system's activation energy (Ea) was found to be 29.11 kJ/mol. Hence, a practical, inexpensive and sustainable process with the potential of high-value platform chemicals, explicitly for a sustainable strategy in a circular bioeconomy was proposed.

In this study, iron was deposited to titanium dioxide nanotube arrays (TNAs) by impregnation method to enhance its photocatalytic ability. The as-synthesized iron-modified TNAs (Fe-TNAs) was employed in a photoelectrochemical (PEC) system to degrade trichloroethylene (TCE). Results of AFE-SEM analysis showed that the iron nanoparticles (NPs) were successfully attached evenly to the nozzle of Fe-TNAs. Results of XRD analysis confirmed the findings of EDS and XPS, indicating the success of iron modification. The absorption wavelength of Fe-TNAs-27 mL red-shifts to 543 nm which corresponds to the band gap of 2.54 eV after iron modification. Mott-Schottky analysis yielded a donor density of 7.21 × 10

Cu2O is a promising material for photocatalysis because of its absorption ability in the ultraviolet (UV)-visible light range. Cu2O deposited on conductive Ti and fluorine-doped tin oxide (FTO) substrates behaves as a photocathode. Cu2O deposited on an n-type semiconductor such as TiO2 nanotube arrays (TNA)/Ti behaves as a photoanode and has demonstrated better photocatalytic activity than that of TNA/Ti. The substrate-dependent photocatalytic properties of Cu2O heterojunctions are not well studied. In this work, the photocatalytic properties of a Cu2O/TNA/Ti junction as a photoanode and of Cu2O/Ti and Cu2O/FTO junctions as photocathodes without bias were systematically studied to understand their performance. The Cu2O/TNA/Ti photoanode exhibited higher photocurrent spectral responses than those of Cu2O/Ti and Cu2O/FTO photocathodes. The photoanodic/photocathodic properties of those junctions were depicted in their energy band diagrams. Time-resolved photoluminescence indicated that Cu2O/TNA/Ti, Cu2O/Ti, and Cu2O/FTO junctions did not enhance the separation of photogenerated charges. The improved photocatalytic properties of Cu2O/TNA/Ti compared with TNA/Ti were mainly attributed to the UV-visible light absorption of Cu2O.

In this study, a farmland contaminated by heavy metals (Cu, Zn, Ni, and Cr) was selected to evaluate the performance of poly-γ-glutamic acid (γ-PGA) on the removal of heavy metals in soil washing. The highest heavy metal concentrations at the contaminated site were Cu: 1180 mg/kg, Zn: 1450 mg/kg, Ni: 287 mg/kg, and Cr: 316 mg/kg. Batch experiments designed by Taguchi Method were conducted first to assess the effect of different washing conditions on the removal of heavy metals in laboratory. The results of batch experiments show that factors that affected the removal efficiency of heavy metals was of the order γ-PGA concentration > washing time > liquid/soil ratio > rotational speed. The optimal operating parameters for heavy metal removal were γ-PGA 3.5%, liquid/soil ratio 15/1, washing time 60 min, and rotational speed 100 rpm. Under the optimal conditions, up to 50.7% of the major target metal, Cu, was removed. Heavy metals in the soil were mainly Fe-Mn oxide bound and organically bound. On-site treatment using the optimal operating parameters caused 54.3% of Cu removal. When the soil was washed 3 times by γ-PGA, the removal efficiency of Cu was improved to 74.3%. After the treatment, the change in soil bacterial number was insignificant, indicating that γ-PGA is an environmentally friendly washing reagent.

Atmospheric particulate matters (PMs) were measured in an industry-intensive region in central Taiwan in order to investigate the characteristics and possible sources of PMs. The samplings were simultaneously conducted using a 10- and 3-stage Micro Orifice Uniform Deposit Impactor (MOUDI) from 2017 to 2018. In this study, the characteristics of PMs in this region were evaluated by measuring the mass concentration of PMs and analyzing water-soluble ions and metallic elements, as well as dioxins. Additionally, principal component analysis (PCA) was used to identify the potential sources of PMs. The results showed that the mean concentration of coarse (&gt, 1.8 μm), fine (0.1–1.8 μm), and ultrafine (&lt, 0.1 μm) particles were 13.60, 14.38, and 3.44 μg/m3, respectively. In the industry-intensive region, the size distribution of ambient particles showed a bi-modal distribution with a high concentration of coarse particles in the spring and summer, while fine particles were dominant in the autumn and winter. The most abundant water-soluble ions of PMs were NO3−, Cl−, and SO42−, while the majority of metallic elements were Na, Fe, Ca, Al, and Mg in different particle sizes. The results of Pearson’s correlation analysis for metals indicated that the particles in the collected air samples were related to the iron and steelmaking industries, coal burning, vehicle exhausts, and high-tech industries. The dioxin concentration ranged from 0.0006 to 0.0017 pg I-TEQ/Nm3. Principal component analysis (PCA) revealed that the contribution to PMs was associated with sea salt, secondary pollutants, and industrial process.

Photo-bioelectrochemical fuel cell (PBFC) represents a promising technology for enhancing removal of antibiotic pollutants while simultaneously sustainable transformation of organic wastes and solar energy into electricity. In this study, simultaneous antibiotic removal and bioelectricity generation were investigated in a PBFC with daily light/dark cycle using oxytetracycline (OTC) as a model compound of antibiotic. The specific OTC removal rate increased by 61% at an external resistance of 50 Ω compared to that in the open-circuit control, which was attributed to bioelectrochemically enhanced co-metabolic degradation in the presence of the bioanode. The OTC removal was obviously accelerated during illumination of cathode in contrast with a dark cathode due to the higher driving force for anodic bioelectrochemical reaction by using photosynthetic oxygen as cathodic electron acceptor during illumination than that using nitrate in dark. The bioelectrocatalytic activity of anodic biofilm was continuously enhanced even at an initial OTC concentration of up to 50 mg L−1. The degradation products of OTC can function as mediators to facilitate the electron transfer from bacteria to the anode, resulting in 1.2, 1.76 and 1.8 fold increase in maximum power output when 10, 30 and 50 mg L−1 OTC was fed to the bioanode, compared to the OTC-free bioanode, respectively. The OTC feeding selective enriched OTC-tolerant bacterial community capable of degrading complex organic compounds and producing electricity. The occurrence of ARGs during bioelectrochemical degradation of OTC was affected more greatly by the succession of the anodic bacterial community than the initial OTC concentration.

Photo-bioelectrochemical fuel cell (PBFC) holds a great potential to harvest sustainable electrical energy from wastewater, but low power output limits its applications due to poor electrochemical performance of photo-biocathode. Additionally, antibiotics are ubiquitous in wastewater streams, but little is known regarding their effects on photo-biocathode performance of the PBFC. This study attempted to increase power output of PBFC through improvement of the photo-biocathode performance by modifying the biocathode with graphene oxide/cobalt/polypyrrole (GO/Co/PPy) composite in the presence of oxytetracycline. The GO/Co/PPy composite modified electrode fabricated by one-step electropolymerization method exhibited more excellent catalytic activity toward oxygen reduction compared to Co-alone and Co/PPy modified electrode. The PBFC with GO/Co/PPy composite modified biocathode produced a maximum power density of 19 mW/m2, which was almost 4-fold higher than that produced with the bare biocathode (4.9 mW/m2) due to improved bio-electrocatalytic performance of the bicathode by the GO/Co/PPy composite. The maximum power density of the PBFC was further increased 4.6 (105.5 mW/m2), 3.7 (88.7 mW/m2), 2.9 (74.6 mW/m2) and 1.9 (56 mW/m2) fold by exposure to 5, 10, 20, and 50 mg/L OTC, respectively. The further increases in power was due to reduced cathode's charge transfer resistance using degradation products of OTC as mediators and OTC-stimulated growth of species with extracellular electron transfer ability. However, the photosynthesis and growth of alga was negatively affected by OTC concentration higher than 10 mg/L, resulting performance deterioration of bicathode.

In this study, cuprous oxide modified titanate nanotube arrays photocatalyst (Cu2O/TNAs), a p-n type hetero-structure, was successfully synthesized by square wave voltammetry electrodeposition method (SWVE) with copper (II) acetate monohydrate as precursor. Cu2O/TNAs photocatalysts were characterized by SEM, XRD, XPS, and UV–vis DRS to investigate the physical and chemical properties such as surface structure, light absorption, and element composition. Results of characterization indicated that the Cu2O nanoparticles (Cu2O NPs) were firmly deposited on the surface of TNAs without significant morphological change. The enhanced photocatalytic (PC) performance of as-synthesized materials was exemplified by the test of photocurrent, which revealing that the average photocurrent density of Cu2O/TNAs (0.95 μA cm−2) was 1.38 times higher than TNAs (0.69 μA cm−2) under 24.2 mW cm−2 LED irradiation. Three VOCs (volatile organic compounds), namely, Toluene, Formaldehyde and Trichloroethylene can be completely removed in the Cu2O/TNAs PC process with rate constants (kobs) of 2.08 × 10−2, 3.11 × 10−2, and 6.58 × 10−2 min−1, respectively, with the effort of the synergism of the photo-generated holes and hydroxyl radicals. Detail mechanism of hetero-junction Cu2O/TNAs composite PC system was proposed to clarify the redox reaction.

Cu

This study aimed to produce a clean energy, hydrogen, and to remove pollutants simultaneously in water by photoelectrochemical (PEC) method. The photo-anode of cuprous oxide modified titanate nanotube arrays (Cu

Silver deposited titanate nanotube array composite (Ag/TNA-c) was successfully synthesized using tea leaves and ground coffee as reducing agent for the first time. The synthesis method was effective, eco-friendly, and reproducible in producing quality nano-composite. The Ag/TNA composite was characterized via XPS, SEM, UV-vis, XRD, and electrochemical analyses for chemical and physical properties. Additionally, chlorogenic acid, caffeine, and catechin were selected as reducing agents for purpose of comparison. Results indicated that catechin and chlorogenic acid were the main reducing agents responsible for Ag+ reduction in tea leaves and ground coffee, respectively. The synthesized Ag/TNA-c exhibited the best photocatalytic (PC) performance in terms of photo-current response, EIS, Ibuprofen degradation, and hydrogen generation in a PEC system. Pairing with a Pt cathode, the photoelectrochemical (PEC) system using the synthesized Ag/TNA composite photo-anode, was capable of concurrent anodic oxidation of Ibuprofen and cathodic generation of hydrogen. Deposition of nano-Ag particles on TNA enhanced the concurrent oxidation and reduction reaction in the PEC system. Results of ESR analysis confirmed the role of hydroxyl radical on Ibuprofen degradation over Ag/TNA-c in the PEC system. Mechanism of Ag/TNA PEC system was proposed to illustrate the oxidation and reduction reaction.

Rice husk is a bulky byproduct with a high silica content from rice milling. In this study, the application of an acid-catalyzed ionic liquid (IL) pretreatment was studied for processing rice husks with a rugged structure. The pretreatment conditions were 130°C for 30 min with 1.2 wt% HCl. The results of enzymatic hydrolysis demonstrated that cellulose conversion of HCl-BMIMCl-treated at 48 h was increased by 660.05%, 538.81%, and 376.55% compared with the untreated, HCl-treated, and BMIMCl-treated rice husks, respectively. Composition analysis demonstrated that most of the hemicellulose was removed in the acid-IL combined treatment. Moreover, scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared analyses indicated that the crystalline structure and outer silica layer of the rice husks were efficiently broken up. The results revealed that the HCl-catalyzed dissolution is highly favorable for the industrial application of rick husks in the production of fermentable sugar and high-purity silica.

Chlorine-containing organic compounds were discharged informally as a result of untreated industrial wastewater, which caused groundwater pollution. In this study, titanium dioxide nanotube arrays (TNAs) were modified with copper oxide to photoelectrochemical (PEC) active persulfate to degrade trichloroethylene (TCE). The SEM results show copper nano-particles with a cubic shape were successfully deposited on the surface of TNAs. The results of UV–vis analysis indicate the absorption wavelengths red-shift to 550–600 nm for better light utilization. CuO/TNAs were dominated by the anatase phase after sintering at 450 °C with significant visible light response. The chemical contents for the surface of CuO/TNAs are 23.7, 53.4, 18.4 and 4.4% for C, O, Ti and Cu, respectively. The photocurrent of CuO/TNAs is 1.89 times higher than that of TNAs-93 cm^2–1hr under 100 W Hg-lamp illuminations. This demonstrates the efficiency of light utilization of TNAs was improved by the modification with copper nanoparticles. The degradation rate of TCE in the anodic chamber is more effective than that in the cathodic chamber because of the synergistic effect of hydroxyl and sulfate radicals. The mechanism of TCE degradation via persulfate in the PEC system was proposed and discussed in detail.

This study employed BiOI-deposited TiO2 nanotube arrays (BiOI-TNTAs) electrode in a photoelectrochemical (PEC) system to oxidize Ibuprofen and generate hydrogen in the anodic and cathodic chamber, respectively. FESEM results revealed the diameter of TiO2 nanotubes was 90-110nm. According to the XRD analysis, the BiOI-TNTAs were dominated by the anatase phase and tetragonal structure of BiOI. XPS results confirmed the coexistence of BiOI in the BiOI-TNTAs associated with Bi (33.76%) and I (8.81%). UV-vis absorption spectra illustrated BiOI-TNTAs exhibit strong absorptions in the visible light region. The PEC method showed the best degradation efficiency for Ibuprofen is a rate constant of 3.21×10-2min-1. The results of the Nyquist plot revealed the recombination of photogenerated electron-hole pairs was inhibited as the bias potential was applied. Furthermore, the Bode plot demonstrated the lifetime (τel) of photoexcited electrons of BiOI-TNTAs was 1.8 and 4.1 times longer than that of BiOI-Ti and TNTAs, respectively. In the cathodic chamber, the amount of hydrogen generation reached 219.94μM/cm2 after 3h of reaction time.

The study investigated the exposure of spray painters to organic solvents, toxic metals, and hexavalent chromium over 21 working days in 2017. The results found these concentrations of 12 VOCs to be below the short-term exposure limit (STEL) established by the US Occupational Safety and Health Administration (OSHA). The mass concentration of total particulate matter (PM) exposure to workers was 20.01 ± 10.78 mg/m3, which exceeds OSHA’s permissible exposure level of 15 mg/m3. The mean concentration of the total metals for all particle sizes was 109.1 ± 12.0 μg/m3, and those for lead (496,017.0 ng/m3) and iron (252,123.8 ng/m3) were the highest of metal elements. Significantly, the mean concentrations of Pb and As exceeded OSHA’s permissible exposure limits (PELs) of 0.05 and 0.01 mg/m3, respectively. The total hexavalent chromium concentration was 1163.01 ng/m3, and the individual particle sizes (PM1−2.5, PM1, and PM0.25) were strongly and positively correlated with the Cr(VI) concentrations for PM2.5. The study determined that approximately 56.14% of the hexavalent chromium inhaled during the spray-painting process was deposited in the upper respiratory system of the head airway region, followed by the alveolar and tracheobronchial regions, with fractions of 11.93 and 0.05%, respectively. Although the mean ratio of hexavalent chromium to total chromium was only 3.6% for all particle sizes, the cancer risk of the total particles in Cr(VI) (1.6 × 10−3) exceeded the acceptable risk value (10−6). The cancer risks of As and Cr(VI) associated with quasi-ultrafine particles, PM0.5–1, PM1–2.5, and PM> 2.5, also exceeded 10−6. Comparison of the carcinogenicity risk of VOCs and metals suggests that the adverse health effect of inhaled particles on spray-painting workers is more serious than that from VOC exposure.

This study applied catalytic (AC/Ag) ozonation combined with hydrogen peroxide (H2O2) to investigate the feasibility of tetramethyl ammonium hydroxide (TMAH) decomposition. The synthesized catalysts were characterized using X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The pH of the isoelectric point of AC/Ag was 10.8. Subsequently, the removal efficiency of the system was examined using operational parameters such as pH condition (3, 5, 7, 9, 11, and 12), AC/Ag dosage (0.5, 1, 1.5, and 2 g/L), and H2O2 (4.4, 8.8, 17.6, and 26.4 mM). The results revealed that the optimal mineralization rate of TMAH was 72% when using the 1.5 g/L AC/Ag catalyst combined with 8.8 mM H2O2 at pH 11. The removal rate of 500 mg/L-TMAH was 81%, and the end products in nitrate and ammonium were 167 mg/L and 102 mg/L, respectively, for a 60 min reaction time. Tert‑butyl alcohol (TBA) was used as an •OH scavenger to assess the contributions of direct and indirect ozonation. The results indicated that indirect ozonation dominated in TMAH mineralization. The calculated krad value of the AC/Ag/H2O2 ozonation method was 1.91 × 10−2 min−1, which was higher than that in the AC/Ag ozonation (1.21 × 10−2 min−1) and sole ozonation (1.70 × 10−3 min−1) methods.

The health and environmental effects of metal-containing carbon black (CB) particles emitted from a CB feeding area near a tire manufacturing plant were investigated. The mass ratios of PM1 and PM0.1 (UFPs) relative to TSP were 13.84% ± 4.88% and 50.84% ± 4.29%, respectively. The most abundant elements in all fractions were Fe, Al, and Zn. The mean percentage contributions of Al, Fe, Zn, Cu, and Co to the coarse particles ranged from 49.1% to 69.1%, thus indicating that the Al, Fe, and Zn contents in the CB particles were affected by workplace emissions. The ratios of the total mean deposition fluxes of atmospheric particle-bound heavy metals in the human respiratory tracts of workers/adults, workers/children, and adults/children were approximately 5.5, 11.0, and 2.0, respectively. The integrated risks of five elements via two exposure pathways to adults and children were 1.1 × 10−4 and 1.7 × 10−5, respectively; these numbers reflect the high cumulative carcinogenic risk posed by these toxic metals to local residents (both adults and children; limit, 10−6). These results demonstrate the potential health risk presented by particle-bound heavy metals to humans residing near tire manufacturing plants via inhalation and dermal contact exposure.

This study aimed to produce a clean energy, hydrogen, and to remove pollutants simultaneously in water by photoelectrochemical (PEC) method. The photo-anode of cuprous oxide modified titanate nanotube arrays (Cu2O/TNTAs) was synthesized by using lactic acid, green tea, and coffee as reductants individually. The characterizations of Cu2O/TNTAs were performed by ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS), field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) to investigate the physical and chemical properties such as structure, crystallization, element contents, and optical performance. The electrochemical analyses of Cu2O/TNTAs showed the photo-current of Cu2O/TNTAs-t (using green tea as reductant) was 2.4 times higher than pure TNTAs, illustrating the effective separation of electron-hole pairs after Cu2O modification. The photoelectrochemical performances of Cu2O/TNTAs-t and Cu2O/TNTAs-c (using coffee as the reductant) were better than Cu2O/TNTAs-L (using lactic acid as the reductant) in terms of photo-current density, Ibuprofen degradation, and hydrogen generation, implying that depositing Cu2O on TNTAs can significantly improve the electron mobility by reducing the recombination rate of electron-hole pairs, which is beneficial to simultaneously ibuprofen degradation and hydrogen production.

This study investigated the possibility of enhancing the disruption of water hyacinth (WH) in an ultrasound-ionic liquid (US-IL) pretreatment assisted by sodium dodecyl sulfate (SDS). 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was used to dissolve the WH. The optimum concentration of SDS for the highest production of reducing sugar was also determined. Compared to the US-IL pretreatment, the production of reducing sugars, cellulose conversion and delignification were increased by 72.23%, 58.74% and 21.01%, respectively, upon addition of 0.5% SDS. Moreover, the enhancement of SDS in the US-IL pretreatment was confirmed by the analysis of structural features, which demonstrated that the SDS increased the removal of lignin and decreased the cellulose crystallinity.

A novel anthraquinone-2,6-disulfonate/MnOx-doped polypyrrole film (AQDS/Mn/PPy) electrode was prepared by one-step electropolymerization method and was used to improve performance of a reversible photo-bioelectrochemical cell (RPBEC). The RPBEC was operated in polarity reversion depended on dark/light reaction of alga Chlorella vulgaris by which sequential decolorization of azo dye and mineralization of decolorization products coupled with bioelectricity generation can be achieved. The results showed that formation of uniform AQDS/Mn/PPy film significantly enhanced electroactive surface area and electrocatalytic activity of carbon electrode. The RPBEC with AQDS/Mn/PPy electrodes demonstrated 77% increases in maximum power and 73% increases in Congo red decolorization rate before polarity reversion, and 198% increases in maximum power and 138% increases in decolorization products mineralization rate after polarity reversion, respectively, compared to the RPBEC with bare electrode. This was resulted from simultaneous dynamics improvement in half-reaction rate of anode and photo-biocathode due to enhanced electron transfer and algal-bacterial biofilm formation.

In this study, electrodes of titanium dioxide nanotube arrays (TNAs) were successfully synthesized by applying the anodic oxidation etching method, as well as the use of green synthetic technology to add reducing agents of tea or coffee to reduce metal palladium from palladium chloride. Synthesis of palladium modified TNAs (Pd/TNAs) was conducted by the microwave hydrothermal method after the metal palladium was reduced. In order to identify the surface structure, light absorption and elemental composition, TNAs and Pd/TNAs were characterized by X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Furthermore, to test the photocurrent density, electron resistance, and hydroxyl radicals by I-t plot, electrochemistry impedance spectroscopy (EIS), and electron paramagnetic resonance (EPR) were investigated. The photocurrent (4.0 mA/cm2) of Pd/TNAs-C (using coffee as the reducing agent) at +1.0 V (vs. Ag/AgCl) was higher than that of the pure TNAs (1.5 mA/cm2), illustrating that Pd/TNAs-C can effectively separate photogenerated electrons and holes. Pd/TNAs is a favorable material as a photoanode for the photoelectrochemical (PEC) removal of organic pollutants in wastewater.

The aim of this work was to study an environmentally friendly method for pretreating rice straw by using 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) as an ionic liquid (IL) assisted by surfactants. Different temperatures, reaction times, and surfactant concentrations were studied. Compared with [BMIM]Cl only pretreatment, the addition of 1% sodium dodecyl sulfate (SDS) and 1% cetyl trimethyl ammonium bromide (CTAB) increased lignin removal to 49.48% and 34.76%, respectively. Untreated and pretreated rice straw was thoroughly characterized through FTIR, XRD, and FE-SEM. Cellulose crystallinity and surface morphology of the rice straw were substantially altered after surfactant-assisted IL pretreatment. In conclusion, surfactant-assisted IL pretreatment is an effective method for producing fermentable sugars from lignocellulosic substrates.

Biocathode microbial fuel cell performances with respect to azo dye decolorization and electricity generation were examined using two anodic inoculums, textile dyeing sludge (MFC-I) and municipal sludge (MFC-M), to determine the potential performance regulation of the MFC via the selection of anodic inoculum. The results showed that the MFC-I exhibited excellent performance in Congo red decolorization, whereas the MFC-M performed well in electricity generation. The MFC-I achieved fast Congo red decolorization with a first-order rate constant k = 0.0501, which was 34% higher than that obtained by MFC-M (k = 0.0375). The MFC-M exhibited 3.22 times higher power output (29 mW/m2 vs. 9 mW/m2) and 38.0% lower anode impedance (749 Ω vs. 1208 Ω) compared to MFC-I. The functional stains isolated from the anodic biofilm of MFC-I were identified as Pseudomonas sp. and Aquamicrobium sp., while isolates from MFC-M belonged to Pseudomonas sp. and Bacillus sp. Four selected isolates were proved to be exoelectrogens and bacterial decolorizer simultaneously but exhibited different bioelectrocatalytic activities and dye decolorizing capabilities, which could partly explain the performance difference between the two MFCs with different anodic inocula.

High-concentration nitrogen removal coupled with bioelectric power generation in an algal-bacterial biocathode photo-bioelectrochemical system (PBES) was investigated. The PBES can self-sustaining operation with continuous power output under day/night cycle by alternately using photosynthetic dissolved oxygen and nitrate/nitrite as cathodic electron acceptors. The PBES generated a high maximum power of 110mw/m2 under illumination and relatively lower power of 40mw/m2 under dark. The bioelectricity generation was accompanied by high-concentration nitrogen removal in the algal-bacterial biocathode. The NH4 N was removed completely within 120 h while maximum NO3 N removal efficiency of 86% and maximum total nitrogen removal efficiency of 83% can be reached after 192 h at initial NH4 N concentration of 314 mg/L and NO3 N concentration of 330 mg/L. Combined processes of bioelectrochemical reduction and algal-bacterial interactions provided multiple approaches for nitrogen removal in the biocathode, including nitrifying using photosynthetic oxygen, bioelectrochemical denitrification using the cathode as electron donor, heterotrophic denitrification using photosynthetically produced dissolved organic matters as carbon source and algal-bacterial uptake. Accelerated nitrogen removal with simultaneously improved cathode performance was observed at high concentration of nitrogen and phosphate buffer due to enhanced algal activities for photosynthetic oxygen release and enhanced algal-bacterial interactions for nitrogen transformation. Addition of external organic carbon negatively affected nitrification and decreased cathode potential due to oxygen consumption by aerobic carbon oxidation but enhanced denitrification due to continuous release of high concentration of photosynthetically produced dissolved organic matters by alga. The PBEC was demonstrated as an energy-saving approach for high-strengthen nitrogenous wastewater treatment.

Dispersants including Tween 20, Tween 40, Tween 60, and polyacrylic acid (PAA) were used to modify nanoscale zero-valent iron (nZVI). All dispersants dispersed nZVI effectively. PAA-modified nZVI was more stable than nZVI that was modified with Tween surfactant. Iron nanoparticles that were prepared using 0.5–5.0% (vol%) of PAA remained in suspension for more than 2 h. nZVI that was modified using Tween surfactant remained in suspension for 30–60 min, and there was complete sedimentation of bare iron in 10 min. When 2.0–5.0% (vol%) of Tween surfactant was used, the stability of the nZVI that was modified using Tween 20 was much better than that for nZVI that was modified using Tween 40 or Tween 60. The results for the transportation test show that nZVI that was prepared using 2% (vol%) of Tween 20 exhibited the best mobility in porous media. Approximately 83–90% of TCE was degraded by bare, PAA-modified, and Tween 20-modified nZVI, and about 63–67% of TCE was removed by nZVI that was modified using Tween 40 and Tween 60 during 20 days of reaction. The production of cis-dichloroethene (DCE) and 1,1-DCE demonstrates that TCE is removed via reductive dechlorination. The results of this study show that PAA- and Tween 20-modified nZVI are more practical for in situ remediation because they exhibit good mobility and degrade TCE effectively.

This study employed BiOI-deposited TiO

Carbon and nitrogen were co-doped into TiO 2 nanotube arrays (C–N-TNTAs) to extend their light response region using the chemical bath deposition method. The as-synthesized C–N-TNTAs were employed as the working anode in photoelectrochemical (PEC) experiments. Using the applied bias potential, the recombination of photo-generated holes and electrons was reduced significantly. The crystalline, optical properties, surface morphology, and structure of the C–N-TNTAs were characterized by XRD, UV–vis absorbance edges, SEM, and XPS, respectively. The XRD results showed the C–N-TNTAs were dominated by the anatase phase after sintering at 450 °C with significant visible light response. XPS analyses indicated nitrogen doping was mainly responsible for reducing the band gap as evidence of 0.82% N doping into the structure via the linkage of the Ti O N and N Ti O bond. SEM images illustrated the diameter of the supported TiO 2 nanotubes was approximately 90–100 nm with a length of approximately 400 nm. After carbon and nitrogen co-doping, the nanotubular structure of TiO 2 nanotube kept its integrity with no significant morphological change, which was beneficial for PEC applications. The degradation efficiency of methyl orange (MO) was examined by photoelectrochemical, photocatalytic, electrochemical and photolysis methods for comparison in terms of pseudo-first-order reaction rate. The PEC method had the best MO degradation efficiency with a rate constant of 2.3 × 10 −3 s −1 at a bias potential of 1.0 V (vs. SCE) under illumination, that was consistent with results of IPCE (%) measurements (the maximum IPCE up to 30.02% at 325 nm wavelength). The synergetic effect was quantified at current/time curves at bias potentials of 0.03 mA/0 V and 3.0 mA/1.0 V, respectively. Electrochemical impedance spectroscopy (EIS) measurements revealed the electron lifetime τ el of photoexcited electrons in photoanodes was increased about 3.2 times after C N doping treatment. The bias potential could separate photo-generated holes and electrons effectively and enhance the electrochemical-oxidation of MO. Hydrogen generation was concurrently conducted in the cathodic chamber. After 180 min of reaction time, the amount of H 2 reached 3.2 mmol by employing C–N-TNTAs as the photoanode.

Microwave-induced nitrogen-doped titanate nanotubes (NTNTs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), Zeta potential analysis, specific surface area (SBET), and UV–Visible spectroscopy. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti–O–N linkage observed in the XPS N 1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. FT-IR results demonstrated the existence of H3O+, which could be excited by photo-generated holes to form hydroxyl radicals and degrade environmental pollutants. After sintering at 350°C, the UV–Vis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic degradation of Rhodamine B (RhB) via NTNTs show good efficiency, with pseudo first-order kinetic model rate constants of 3.7 × 10− 3, 2.4 × 10− 3 and 8.0 × 10− 4 sec− 1 at pH 3, 7, and 11, respectively.

This study employs a rapid, energy frugal and environmental friendly method to synthesize nitrogen doped titanate nanotubes (NTNTs), and uses TEM, XRD, Raman, Nitrogen adsorption-desorption isotherms analysis, and UV-vis spectroscopy to characterize the obtained NTNTs. TEM results indicate that NTNTs retain a tubular structure with a crystalline multiwall and have a length of several hundred nanometers after nitrogen doping. XRD findings demonstrate that the crystalline structure of NTNTs was dominated by anatase, which is favored for photocatalytic application. The Ti-O-N linkage observed in the XPS N1s spectrum is mainly responsible for narrowing the band gap and eventually enhancing the visible light photoactivity. After sintering at 350 °C, the UVvis absorbance edges of NTNTs significantly shift to the visible-light region, which indicates N atom doping into the nanotubes. Photocatalytic tests conclude that the NTNTs shows good efficiency with visible light response.

This study is the first one investigating the correlation between the concentration of polycyclic aromatic hydrocarbon (PAHs) in blood and semen qualities for residents in the Pearl River Delta (PRD) region in China. Blood samples from 53 infertile volunteers were studied for measures of semen quality and 16 PAHs. Information on the study subjects' living habits (such as smoking, drinking and preference of consumption for food) and general information (age, body-mass-index (BMI) and educational background) were also collected. Statistical results showed that age and BMI were significantly and negatively related to semen motilities. The total concentrations of PAHs (∑16 PAHs) in the blood were 12,010, 7493, 9105 and 8647ng/g for factory workers, office workers, technicians and salespersons, respectively. In addition, ∑16 PAHs in the blood of smokers, drinkers and heavy-taste food consumers were 11,950, 11,266 and 12,141 ng/g, which were higher than those observed in nonsmokers (10,457 ng/g), nondrinkers (10,920 ng/g) and light-taste food consumers (9202 ng/g), individually. Furthermore, the Pearson correlation analysis results showed significant positive correlations between BMI and ∑16 PAHs in the blood. Statistically significant correlations were observed between semen motilities and ∑16 PAHs in the blood as well. Logistic regression results showed that for each 1 ng/g increase in ∑16 PAHs in blood samples, the log odds of experiencing a pregnancy decrease by 0.039 on average. However, more evidences are needed to clarify the impact of PAHs in the blood to male infertility. Keywords: Polycyclic aromatic hydrocarbons, Whole blood, Semen quality, Male infertility, Pearl River Delta

We studied CO 2 reduction using a solar cell driven photoelectrochemical (PEC) reactor in dilute aqueous KHCO 3 (0.1 M) solution. Results show that CO 2 was reduced to four major hydrocarbon species, namely, formic acid (HOOH), formaldehyde (HCOH), methanol (CH 3 OH), and methane (CH 4 ). Over a reaction time of 5 h, the product yield was 1.55, 0.62, 2.02, and 2.16 μM with a current efficiency of 0.22%, 0.17%, 0.84% and 1.2%, for HCOOH, HCOH, CH 3 OH, and CH 4 , respectively, whereas hydrogen, produced from water electrolysis, exhibited the highest current efficiency of 54.23%. It is also noted that the production of organic carbons was enhanced by increasing the CO 2 concentration due to the presence of methanol. Results showed that methanol hindered hydrogen formation and increased the yield of organic carbons. Furthermore, the degradation of an azo dye, namely, methyl orange (MO) was observed using PEC process under different applied currents. The degradation rate was increased by two orders of magnitude when a bias potential was applied to the solar cell system. Our results demonstrated the potential of solar energy for CO 2 conversion to energy-rich organic carbons and the remediation/purification of impaired water.

We investigated the synergetic effect of electrochemical and photocatalytic oxidation in photoelectrochemical (PEC) process for the degradation of hazardous organic compounds exemplified by methyl orange, an azo dye. Nitrogen doped TiO 2 thin film (NTTF) synthesized by the pulsed laser deposition (PLD) method, was used as the working anode. The crystalline, optical properties, surface morphology, and structure of the NTTF were characterized by XRD, UV–vis absorbance edges, SEM, and XPS. Results showed that the NTTF was dominated by anatase phase after sintered at 600 °C with significant visible light response at 595 nm. XPS analyses indicated nitrogen doping was mainly responsible for reducing the band gap as evidence of 3% N doping into the structure via the linkage of Ti O N and N Ti O bond. SEM images illustrated the nitrogen-doped TiO 2 nanoparticles being attached firmly and spread evenly over the ITO glass surface, which is beneficial for PEC applications. The degradation efficiency of MO by photoelectrochemical, photocatalytic, electrochemical and photolysis methods were compared in terms of pseudo-first-order reaction rate. PEC was the most efficient in degrading MO at a bias potential of 2.0 V (vs. SCE) under light at a wavelength of 325 nm, which was consistent with results of IPCE (%) measurements. The synergetic effect was quantified at current/bias potential of 0.07 mA/0.3 V and 0.6 mA/2.0 V, respectively. Results demonstrated that the bias potential could separate photogenerated holes and electrons effectively and enhance the electrochemical-oxidation of MO. The mechanistic aspects of MO degradation by the PEC process were discussed.

This study employed a novel material, nitrogen-doped TiO2 thin film (NTTF), as a photoanode for the concurrent photoeletrochemical (PEC) reduction of CO2 and oxidation of methyl Orange (MO). Under illumination, the onset potential of the total current was approximately 1.5 V (vs. SCE) and the maximum total current was around 0.65 mA at 2 V (vs. SCE). The photocurrent can be effectively driven to the counter electrode at this positive potential, which will decrease the recombination of photo-generated holes and electrons, leading to more electrons available for CO2 reduction in the cathodic chamber and more holes for the oxidation of hazardous chemicals in the anodic chamber simultaneously. Formic acid, formaldehyde, methanol and methane were detected as the CO2 reduction products at a Cu electrode in the KHCO3 electrolyte. The first-order kinetic model was successfully applied to simulate the NTTF PEC reduction of CO2. The reaction rate constant were 6.68 × 10−7, 2.18 × 10−4, 8.62 × 10−4 and 2.27 × 10−4 s−1, for the formation of formic acid, formaldehyde, methanol, and methane, respectively. The maximum Faradaic efficiency was 5.01, 1.04, 5.41 and 7.83% for the generation of formic acid, formaldehyde, methanol, and methane, individually. In addition, the effect of initial CO2 concentration on CO2 reduction was also conducted in the presence of methanol (0, 20 and 40%). Results showed that methanol-containing electrolyte enhanced CO2 solubility thereby suppressing hydrogen generation and favoring CO2 reduction. Finally, the degradation of methyl orange was compared using PEC, photocatalytic (PC), electrochemical (EC) and direct photolysis (P) processes. The PEC process was able to achieve a 10-log versus less than 1-log of methyl orange degradation by all other methods studied within 60 min under otherwise similar conditions of pH, temperature, intensity and wavelength of light source. Results clearly demonstrated the potential of a sustainable technology for the concurrent reduction of CO2 and oxidation of hazardous chemicals by the PEC process using solar energy.

A p-n junction Cu2O doped TiO2 nanotube arrays (Cu2O/TNAs) were synthesized by square wave voltammetry electrochemical (SWVE) deposition method and employed as the working anode. The crystalline, optical properties, surface morphology, and structure of the Cu2O/TNAs were characterized by XRD, UV-vis absorbance edges, SEM, and XPS. Results showed that the Cu2O/TNAs were dominated by anatase phase after sintering at 450 °C with significant visible light response. XPS finding confirmed XRD results that the copper element in Cu2O/TNAs was Cu (I) instead of Cu (II). SEM images illustrated the diameter and the length of supported TiO2 nanotubes was approximately 100 nm and 2.75-4.34 μm, respectively. After Cu2O doping, the nano-tubular structure of TiO2 nanotube kept its integrity with no significant morphological change, which was beneficial for PEC applications. The photocurrent of Cu2O/TNAs was 1.45 times larger than that of TNAs, implying that Cu2O doping significantly enhanced electron mobility by reducing the recombination of electron-hole pairs. In addition, electrochemical impedance spectroscopy (EIS) measurements revealed that the recombination of photogenerated electron-hole pairs was inhibited as the bias potential was applied. Results of Bode plot further demonstrated that the electron lifetime τel of Cu2O/TNAs-20 (30.79 ms), under 0.5 V bias potential, was about 2.23 times higher than that of pure TNAs (13.82 ms). Results of electron spin resonance (ESR) analyses demonstrate that the hydroxyl radicals (OH) are responsible for the PEC decomposition of Ibuprofen.