Search

In the last years, large attention has been devoted to the electrochemical treatment of wastewater polluted by recalcitrant organics and containing chlorides. However, the utilization on an applicative scale of this route is limited by the fact that usually it is not possible to achieve high removals of organics without the generation of significant amounts of chlorinated by-products. Here, the role of several operative parameters on the performances of the process was systematically evaluated using phenol as a model organic pollutant. It was shown that the removal of phenol and TOC and the generation of many by-products including chlorophenols, chloroacetic acids, chlorate and perchlorate dramatically depend on the adopted operative conditions (i.e., nature of anode and cathode, current density and concentration of chlorides). The use of boron doped diamond (BDD) anode gave the highest removal of TOC but also the highest final concentrations of chlorate and perchlorate and the lowest concentrations of chloroacetic acids. Conversely, the use of Ti/IrO2-Ta2O5 gave the lowest generation of chlorate and no perchlorate. The use of lower current densities allowed as well to reduce the concentrations of these compounds. It is worth to mention that lower amounts of chlorinated by-products were achieved using suitable cathodes. Carbon felt cathodes, as previously reported for the water disinfection, allowed to reduce the generation of chlorate. Moreover, it was shown, for the first time, that the use of silver cathodes minimized the concentrations of chloroacetic acids. In addition, it was found that the use of a system equipped with both silver and carbon felt cathodes and proper current densities allowed to increase remarkably the removals of TOC and the current efficiency and to achieve very low concentrations of chlorinated by-products.

In this work, a new activated carbon fiber (ACF) cathode modified with graphitic carbon nitride (g-C3N4) was developed, which enables the substantially improved production of H2O2 (up to 32.8 mg L−1) with relatively low energy consumption (10.9 kWh kg−1) compared to generation without g-C3N4 (4.09 mg L−1). The cathode was analyzed and characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction, and it was proved that the synthesized g-C3N4 is a thin layer sheet with a large number of carbon particles and low defect porosity. The cathode manufacturing parameters were optimized, and the influences of H2O2 production including the cathode potential, pH value, aeration rate and performance stability were studied. These features improved the production of H2O2 by about more than 7 folds when optimized ratio of g-C3N4 was used, and the modified cathode kept stable performance of H2O2 generation in 5 cycles. Further discussed by linear sweep voltammetry, rotating disk electrode and contact angle analysis, the existence of g-C3N4 were found to accelerate the electron transfer rate, is advantageous to the surface of the oxygen reaction, but will not change the two electronic number of oxygen reduction reaction activities, and this leads to enhanced performance of hydrogen peroxide production and the possible mechanism was suggested. Finally, the cathode improve by g-C3N4 proved the degradation effect of phenol by photoelectric-Fenton process. Phenol was degraded completely, and 93.8% of the organic carbon was removed, which is more than 1.5 and 5 times the amount achieved using electro-Fenton and photo-Fenton degradation only. In the degradation process of phenol, electrocatalysis and photocatalysis, they were optimized to produce substantial synergistic effect, proving the great potential practical application of organic wastewater treatment.

The aim of this study is to evaluate the removal potential of polyacrylate in aqueous solution by activated sludge. Batch experiments investigated the effects of contact time, pH value, temperature, and concentration of adsorbate on polyacrylate removal by activated sludge to evaluate the isotherms, kinetics, thermodynamics, and mechanisms. The materials were characterized by N2 adsorption-desorption isotherms, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR). The experimental results indicate that more than 90% of polyacrylate was removed by activated sludge in a short time. The adsorption capacity increase with the increase in initial polyacrylate concentration and temperature. Increasing pH value resulted in a decrease in adsorption capacity. The adsorption process fitted well to Langmuir isotherm and pseudo-second-order kinetic models. Thermodynamic parameters indicate that the adsorption of polyacrylate onto activated sludge was feasible, spontaneous, and endothermic. The results of kinetics, thermodynamics, SEM-EDS, and FT-IR showed that surface binding, hydrophobic interaction, and hydrogen bond force may play a major role in the removal process. Microbial community structure analysis by 16S rRNA gene revealed that short-term exposure with polyacrylate had a little negative impact on the activated sludge microorganisms. A better understanding of polyacrylate adsorption onto activated sludge is essential for improving predictions of the fate and transport of polyacrylate in waste water treatment process.

In this work, a new gas diffusion electrode (GDE) of carbon nanotube/graphitic carbon nitride (CNT/g-C3N4) was prepared, which enables the substantially improved production of H2O2 (up to 1083.54 mg L−1) compared to generation without g-C3N4 (400 mg L−1). Characterized by TEM, XRD and XPS, the synthesized g-C3N4 was proved to be a thin layer sheet with low defects. Important cathode manufacturing parameters including the mass ratio of CNTs to g-C3N4 were optimized, and the dependence of H2O2 generation on pH, current density, aeration rate and performance stability were investigated. Further explored by linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) analysis, the presence of g-C3N4 was found to accelerate the electron transfer rate, benefit the oxygen surface reaction, which contributed to the enhanced performance for H2O2 production. Finally, such a CNT/g-C3N4 cathode demonstrated effectiveness for the degradation of alizarin yellow R (AYR) by electro-Fenton (EF), photo-Fenton (PF) and photoelectron-Fenton (PEF) processes. AYR was degraded completely, and 94.8% of the organic carbon was removed, which is more than 5 times the amount removed using PF degradation only. And during the PEF degradation process of AYR, electro- and photocatalysis support and optimize each other, which produces a substantial synergistic effect, proving great potential for practical application in organic wastewater treatment.

This work utilizes nitrogen-doped porous carbon (NPC) and carbon black (CB) to fabricate a novel rolled carbonaceous gas-diffusion cathode by polytetrafluoroethylene (PTFE) as adhesive, which greatly improves the production of H2O2 to 7.27 mg h−1 cm−2 by optimization in near neutral pH condition. Further application of NPC/CB cathode in heterogeneous electro-Fenton (EF) experiments with synthetic pyrite (FeS2) as catalyst, metal sulfides (MoS2, WS2) as co-catalysts, the removal efficiency of the tetracycline (50 mg L−1) could reach 100% and the total organic carbon (TOC) removal efficiency of counterpart could reach 81.3%, respectively. Because of the FeS2 produces H+ and Fe2+ in the presence of H2O2, which provides pH value and catalytic ion that suitable for EF. Meanwhile, the metal sulfides can accelerate the conversion of Fe3+ to Fe2+ by exposing reducible metal active sites on the surface of the catalysts, thus drastically increased the efficiency of H2O2 decomposition and pollutant degradation, also optimized the disadvantage of little Fe2+ leaching from FeS2 in heterogeneous EF. Further tests of this system indicated its potential for the treatment of tannery effluents. It provided an effective and feasible scheme for promoting the improvement of the heterogeneous EF system and the development of practical application.

This study examined the correlation between non-metallic organic tanning agents (NOTAs) and wastewater containing double-triazine (bistriazine). Specifically, high-throughput sequencing was used to analyze how the physical and chemical properties of the bistriazine-containing wastewater affected the microbial community. In total, 9995 operating taxonomy units (OTUs) were detected at a similarity level of 97%. According to the taxonomy results and relative bacterial richness, the non-metallic organic tanning agent (NOTA) wastewater communities showed significant differences. Clostridium sensu stricto and Turicibacter bacteria were dominant in NOTA T2, T3, and the blank control (KB) wastewater, Trichococcus and Aeromonas were dominant in NOTA T4, and Pseudomonas was dominant in T2, T4, and the blank control (KB). Thus, the addition of bistriazine ring derivatives altered the composition of the bacterial community. Furthermore, Spearman’s correlation analysis revealed a substantial correlation in the composition of the communities and the physicochemical properties of the wastewater. Acidocella and norank c Cyanobacteria correlated positively with Total Phosphorus (TP) (p ≤ 0.001) and Mycobacterium showed a positively held correlation with pH (p ≤ 0.05). Conversely, norank_f__Elev-16S-1332 indicated a negative correlation with TP, Total Nitrogen (TN), and Total Organic Carbon (TOC) (p ≤ 0.05), whereas Zoogloea correlated negatively with NH3–N, TOC, and TN (p ≤ 0.05). Regarding water quality, a significant correlation between microbial communities and the physicochemical properties of bistriazine wastewater was also observed (p ≤ 0.05). We concluded that Trichococcus, Clostridium sensu stricto, Turicibacter, Pseudomonas, Intestinibacter, Acidocella, Bacillus, and Tolumonas showed a high tolerance for bistriazine wastewater, which could offer insight into its bioremediation.

Sustainable recycling of valuable metals from spent lithium-ion batteries (LIBs) may be necessary to alleviate the depletion of strategic metal resources and potential risk of environmental pollution. Herein a hydrometallurgical process was proposed to explore the possibility for the recovery of valuable metals from the cathode materials (LiCoO 2 ) of spent LIBs using phosphoric acid as both leaching and precipitating agent under mild leaching conditions. According to the leaching results, over 99% Co can be separated and recovered as Co 3 (PO 4 ) 2 in a short-cut process involved merely with leaching and filtrating, under the optimized leaching conditions of 40 °C (T), 60 min (t), 4 vol.% H 2 O 2 , 20 mL g −1 (L/S) and 0.7 mol/L H 3 PO 4 . Then leaching kinetics was investigated based on the logarithmic rate kinetics model and the obtained results indicate that the leaching of Co and Li fits well with this model and the activation energies (Ea) for Co and Li are 7.3 and 10.2 kJ/mol, respectively. Finally, it can be discovered from characterization results that the obtained product is 97.1% pure cobalt phosphate (Co 3 (PO4) 2 ).

Bioleaching has been demonstrated as a feasible and effective technology for removing Cr(III) from tannery sludge, but the recovery of bioleachate derived from tannery sludge by bioleaching is rarely reported. The purpose of this study was therefore to figure out the components of bioleachate and develop a chromium-iron tanning agent using the bioleachate and reuse it in tanning process. Component analysis indicated that the bioleachate contained high concentrations of Cr and Fe, as well as small quantities of other elements. The dissolved organic matter in the bioleachate was detected to be less than 1000 mg/L, which was mainly composed of polysaccharide, aliphatic or aromatic carboxylic acid compounds. A chromium-iron tanning agent was then prepared using the bioleachate, iron and chromium salts in a suitable ligand environment, and reused for tanning. In the tanning experiments, the pickled pigskins were tanned with this prepared tanning agent and the results indicated that chromium-iron tanned crust leather presented comparable physical and mechanical properties as well as air permeability when compared with conventional chromium tanned crust leather, but the thermal shrinkage temperature was about 4 °C lower than that of the chromium tanned crust leather. Therefore, this study provides not only a reuse route for tannery sludge bioleachate but also a clean tanning agent for leather processing.

Supercapacitors fill the gap between batteries and conventional solid state and electrolytic capacitors. Polypyrrole (PPy) is a very important electrode material for supercapacitors. However, the repeated volume changes usually damage PPy structure and result in PPy poor stability during a long-term charging/discharging process. PPy/carbon material composites were prepared to overcome the defects of pure PPy electrodes, and significant enhancement for the specific capacitance, charging/discharging rate and electrodes stability was demonstrated thereafter. The development of composite electrodes based on PPy and carbon materials is reviewed in this paper.

In this study, in-situ Fenton oxidation was used for the de-complexation and degradation of tannin-Cr(III) complexes. Cr(III) can be oxidized into free Cr(VI) under the effect of ·OH and oxidation products of tannin can be used as reductant for Cr(VI) to establish a redox cycle of Cr(III)-Cr(VI)-Cr(III). Thus, it is crucial to investigate the interactions of Cr(III) with tannin derived oxidation products due to negligible accumulation of Cr(VI) during Fenton oxidation treatment. Here, sequential filtration/ultrafiltration was applied to reveal the distribution characteristics of TOC and Cr fractions during the oxidation of tannin-Cr(III). As the increase of colloidal size of tannic acid products, residual TOC and Cr mainly distribute in larger size range after the oxidation of tannin-Cr(III) which can be ascribed to re-complexation between oxidation products and Cr(III). Besides, analytical results indicate that carboxyl group and hydroxyl group in oxidation products may cause the re-complexation of Cr(III), resulting in the formation of highly conjugated materials containing Cr(III). It can be concluded that due attention should be paid to the efficient removal technology and mechanism for polymer-Cr complexes, as well as the oxidation intermediates in the role of conversion and removal of Cr species.

BACKGROUND AND PURPOSE: Acute ischemic stroke (AIS) patients with history of prior ischemic stroke plus concomitant diabetes mellitus (DM) were excluded from the ECASS III trial due to safety concerns. However, there are few data on use of intravenous tissue plasminogen activator (tPA) and symptomatic intracranial hemorrhage (sICH) or outcomes in this population. METHODS: Using data from the Get With The Guidelines-Stroke Registry (GWTG-Stroke) between February 2009 and September 2017 (n=1619 hospitals), we examined characteristics and outcomes among AIS patients treated with tPA within the 3–4.5 hour window who had a history of prior stroke and DM (HxS+DM, n=2129) versus those without either history (n=16,690). RESULTS: Compared with patients without either history, those with both prior stroke and DM treated with tPA after an acute ischemic stroke had a higher prevalence of cardiovascular risk factors in addition to history of prior stroke, diabetes, and more severe stroke (NIHSS median 8 [IQR 5–15] vs. 7 [4–13]). The unadjusted rates of sICH and in-hospital mortality were 4.3% (HxS+DM) vs 3.8% (without either history) (p=0.31) and 6.2% vs 5.5% (p=0.20), respectively. These differences were not statistically significant after risk adjustment (sICH, adjusted odds ratio [OR] 0.79[95% CI, 0.51–1.21], p=0.28; in-hospital mortality OR 0.77 [95% CI, 0.52–1.14], p=0.19). Unadjusted rate of functional independence (Modified Rankin Scale score [mRS] 0–2) at discharge was lower in those with history of prior stroke and DM (30.9% HxS+DM vs 44.8% without either history, p=

In the last years, the electrochemical conversion of oxygen to hydrogen peroxide at carbon felt has been largely studied in order to define a new route for the production of H2O2 and to optimize the electro-Fenton process, which is based on the cathodic generation of H2O2. In particular, many studies regarding electro-Fenton process were carried out in undivided cells in order to avoid the costs of the separator and to reduce the cell potentials. Hence, in order to optimize the cathodic conversion of oxygen to H2O2 in undivided cells, the effect of many parameters linked to the anodic process were here evaluated. In particular, it was demonstrated that the performances of the process strongly depends on the ratio between the cathode and the anode surfaces, the nature of the anode, the mixing rate and the current density.

The contribution of heat input in traditional photocatalytic processes is rarely studied. Herein, a series of the Ag nanoparticles deposited g-C3N4 (Ag-CN) was prepared by photochemical method and used for photocatalytic CO2 reduction with the assistance of thermal energy. The photocatalytic properties were investigated under light-emitting diode light (420 nm, on the order of solar intensity) irradiation at temperatures up to 200 oC, confirming that the CO evolution rate was strongly dependent on the reaction temperature. The CO production reached to a maximum value of 179.6 μmol•g−1•h−1 (about 4.2 times higher than that of CN) on the 20%Ag loaded CN at 190 °C although negligible photocatalytic activity was observed under light illumination at ambient temperature. The enhancement of the temperature could not only improve the transfer rate and energy of the excited electrons, but also increase the population of the activated molecules, which might contribute to the enhancement on the CO production. Our finding provides an alternative way for integrating infrared light (accounting for ~50% of the solar light) in photocatalysis considering the thermal effect of the infrared light.

The performances of advanced oxidation processes (AOPs) for the removal of refractory dissolved organic matter (DOM) are significantly different due to the various degradation mechanisms and competitive interactions between DOM and AOPs. This research traced the variation and removal of DOM components in tannery wastewater (TW) during conventional treatment, which includes coagulation, hydrolytic acidification/anoxic (H/A), and anaerobic/aerobic (A/O) stages. Electrochemical oxidation (EO) and ozone oxidation (OO) AOPs were conducted to treat a conventional treatment effluent based on selective oxidation and performance. The results demonstrated that the refractory DOM of the secondary effluent of the TW was mainly the hydrophilic neutrals (HIN) fraction (44.1%), which consisted of fatty acids and aliphatic compounds, and the hydrophobic acids (HOA) fraction (28.5%), which included the carboxylic-rich alicyclic molecules (CRAMs) and complex polycyclic aromatic structures. During the conventional treatment, lower molecular weight (MW) aliphatic and protein substances were preferentially removed by the H/A stage, while the A/O stage more completely eliminated hydrophobic aromatic substances of a lower MW. However, humus-like substances increased in both scenarios. With respect to the two AOPs, OO preferentially removed substances with a lower MW, and the HOA fraction converting to hydrophilic humus-like substances followed with more derived by-products. Comparing to OO, EO performed better on the removal of aromatic compounds, especially the humus-like substances (polycyclic aromatic and CRAM-like substances) in HOA fraction, therefore significantly improved the biodegradability of the effluent. The results indicate that EO has a better selectivity for humus-like substances and is suitable for the treatment of refractory DOM containing chloride.

In this study, we demonstrated that hydrothermal synthesized FeS2 was highly efficient to catalyze the H2O2 decomposition for diclofenac sodium (DCF) degradation in a wide range of initial pH (3–9) by heterogeneous electro-Fenton (EF) process, and this “Pyrite-EF” showed a better performance for the mineralization of DCF in comparison with the classic EF process. Effect of pyrite content on the hydroxyl radicals generation and iron dissolution produced by the decomposition of hydrogen peroxide (H2O2), and applied current density on the degradation kinetics and mineralization efficiency were studied. Moreover, toxicity assessment by means of microtox method showed the solution toxicity was removed after treatment. Experimental results revealed that the enhancement of DCF degradation rate in the Pyrite-EF process was attributed to the molecular oxygen activation induced by more surface bound ferrous ions on FeS2, generating superoxide anions to accelerate the Fe(II)/Fe(III) cycle on the FeS2 surface, which favored the H2O2 decomposition to generate more hydroxyl radicals for the DCF degradation via a heterogeneous EF-like process. These findings could provide some new insights into the molecular oxygen activation induced by FeS2 and the subsequent heterogeneous Pyrite-EF degradation of organic pollutants from wastewater.

Efficient and sustainable treatment of real chromium-containing tannery sludge is attracting an increasing concern due to its potentially severe impacts on eco-system and human-beings. In this study, a greener alternative was studied for the removal and recovery of chromium from tannery sludge by ultrasound-assisted supercritical water oxidation approach. Supercritical water oxidation or ultrasonic treatment was respectively conducted to explore the detailed experiment parameters on organic destruction and chromium liberation. Ultrasound-assisted supercritical water oxidation treatment was then investigated to further explore the mechanism for Cr liberation. Experimental results indicate that supercritical water oxidation or ultrasonic treatment cannot effectively remove Cr from tannery sludge, while almost all Cr (99.6%) will be liberated to supernatant at optimized experimental conditions by ultrasound-assisted supercritical water oxidation treatment, with TOC removal efficiency over 99.9%. This indicates that toxic substances in sludge will be completely removed after ultrasound-assisted supercritical water oxidation treatment, and liberated Cr in the supernatant can be re-utilized after purification. This process is an efficient alternative for toxicity removal and chromium recovery from real tannery sludge contaminated by high concentration of Cr and refractory organics.

Graphene Oxide (GO) has wide applications in many fields which has caused a large expected quantity of the graphene-based wastes. It is necessary to understand the toxic effects of the GO on the activated sludge (AS) considering its inevitable discharge to the wastewater treatment plants as the ultimate repositories for these wastes. In this study, the acute exposures of the multilayer Nano-graphene oxide (MNGO) at different dosages were conducted in order to investigate its integrated effects on the formation of the biofilm, mature biofilm and the microbial activity of the activated sludge. Raman spectroscopy and laser scanning confocal microscopy (LSCM) were adopted for the in-situ characterization of the biofilm with the exposure of the MNGO. The results showed that the activated sludge was tolerable to the acute exposure of the less than 100 mg/L of the MNGO, especially for the mature biofilm, and only a subtle decrease was found in the size and thickness during the formation of the biofilm, while the amount of 300 mg/L of the MNGO caused the sever deterioration on the activated sludge system. The microbial metabolic activity, viability, and the biological removal of the nutrients were significantly affected with the more than 100 mg/L of the MNGO. It was also demonstrated by the microbial cytotoxicity tests that the increase in the exposure of the MNGO was related to the increase in the reactive oxygen species (ROS) and the damaging degree of the cell membrane.

Wastewater treatment has become a major global issue due of undegradable pollutants. As toxic water pollutants, namely o-toluidine and p-toluidine are difficult to treat, this study uses the silicon rubber technology to treat them. A pair of modules having single tabular nonporous silicon rubber tube and HCl stripping solution were set up to extract o-toluidine and p-toluidine from high-saline wastewater. Reaction quotient ( Q C ) was calculated after every 12 h intervals to evaluate the equilibrium reaction. The effect of concentration, pH, temperature, ionic strength, and flow rate on the permeability (P) and removal efficiency ( η ) were investigated to illustrate the process parameters and mechanisms of recovery of both elements from wastewater. The results showed that the recovery efficiency was more than 96% with concentration of 2–10g/L. When pH of the extraction solution was 2 or less, the pollutant permeability efficiency was nearly 95%. Moreover, when the salting strength was over 10%, the recovery efficiency increased quickly to some extent. Permeability, which mainly influenced by membrane resistance and desorption rate, initially increased and then decreased when the water flow increased from 2 and 20 mL/min. Aging of silicon rubber tube was also studied with respect to salinity, temperature, and acidity. Acidity and temperature was found to have a significant effect on the tube, permeability increased with an increase in aging, and aging had a minor effect on the elastic properties of the silicon rubber tube. Absorption and diffusion of water in silicon rubber tubes decreased when salinity increased more than 10%, which increased separation of p-toluidine and water. Due to this, there is no need of desalination before membrane extraction in treatment of p-toluidine wastewater with high saline. Thus, this study demonstrates that membrane extraction is a highly energy-efficient process for the effective recovery of o-toluidine and p-toluidine from wastewater with high salinity.

Efficient recycling of valuable components, especially high value-added parts, from spent lithium ion batteries (LIBs) is of great importance to alleviate or avert current environment-related issues and growing resources depletion. Current study established a novel process for in-situ separation and recycling of both coating materials and Al foils from spent LIBs using ultrasonic-assisted acid scrubbing method. Waste cathodes obtained after pretreatment were cut into smaller pieces, put into a self-designed ultrasonic reactor and immersed in different aqueous solutions for scrubbing experiments. Experimental data proves that acidic solutions (i.e. sulfuric and oxalic acidic media), even quite dilute solutions, can significantly improve peeling off efficiency and Al purity, instead of pure water ultrasonic scrubbing. About 99%, 100% and 46% coating materials can be detached in sulfuric acidic, oxalic acidic and pure water medium, respectively, leaving these Al foils with a corresponding purity of 98%, 99% and 15%. The possible cause for the prompt peeling off coating materials may be rapid degradation of binders by the strong oxidation of HO· radicals formed and strengthened in acidic ultrasonic solutions. Net profits of $2.587 or $2.043 per kg spent batteries can be achieved in sulfuric or oxalic acidic ultrasonic scrubbing system. This recycling process may suggest an alternative for in-situ recycling of cathode materials and Al foils from spent LIBs, with simplified separation procedure and enhanced recycling efficiency and product purity.

This study has investigated a novel jet-type reactor (vertical flow reactor) in order to improve the oxygen utilization for enhanced production of hydrogen peroxide (H2O2). In vertical flow electro-Fenton (EF) system, the effects of current density, water flow rate, Fe2+ concentration and initial pH were investigated for the removal of tetracycline hydrochloride. The efficient removal of tetracycline hydrochloride could reach 100% within 60 min under the current density of 24 mA cm−2, water flow rate of 10 L h−1 and pH of 3. The vertical flow reactor was relatively stable and reusable for the removal of pollutants. The removal rates of tetracycline hydrochloride and total organic carbon (TOC) were maintained at about 95% and 80%, respectively in a 5-time continuous runs. Moreover, the vertical flow reactor could efficiently remove a wide type of organic pollutants, and the TOC removals of acid magenta, rhodamine B, alizarin yellow R, orange Ⅳ and diclofenacdium were 75.96, 77.90, 61.27, 72.11 and 82.89%, respectively after 3 h of reaction time. Cathodic adsorption, anodization, and H2O2 oxidation played minor roles in the removal of tetracycline hydrochloride, while the OH radicals are the most pivotal oxidizing substance in the system. As compared with the traditional aeration, the vertical flow reactor has a high-speed jet flow state, which makes the liquid-gas mixture homogeneous, and renders it high oxygen absorption rate, cost effectiveness and high power efficiency for the degradation of pollutants.

In this work, the active carbon fibers (ACFs) was modified by zeolitic imidazolate framework-8 (ZIF-8) to prepare a novel modified electrode as cathode. The effect of different amount of ZIF-8 modified ACFs (0–0.30 g) on H2O2 production and electric energy consumption (EEC) were investigated and the optimal ZIF-8 amount was 0.15 g. Characterized by linear sweeping voltammetry (LSV), electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), contact angle, and X-ray photoelectron spectroscopy (XPS) after modification were observed considerably changed. Some nanoparticles and oxygen-contained functional groups appeared on the ZIF-8/ACF cathode surface, which significantly enhanced the hydrophilic property and the electrochemical performance. It was observed that H2O2 production with 0.15 g-ZIF-8/ACF as cathode (1545.1 mg L−1) was much larger than with raw ACF as cathode (64.1 mg L−1). Meanwhile, H2O2 production could also achieve a balance in a high state of H2O2 production (around 1500 mg L−1) with low EEC ( OH radicals could be generated in the EF system with 0.15 g-ZIF-8/ACF. Therefore, EF system with ZIF-8/ACF cathode is a good alternative process for pollutant removal.

As a hazardous waste, the disposal of chromium enriched tannery sludge has attracted increasing public concern due to its potential adverse risks towards the environment. And incineration is considered to be an effective method to stabilize heavy metals, like Cr, in solid phase during tannery sludge treatment. In this study, real chromium enriched tannery sludge without pre-treatment was incinerated at 300°C–1200 °C under air atmosphere to investigate the transformation of chromium speciation. Here detailed thermal behavior, phase transformation and chromium speciation were characterized by TG-DSC, XRD and XPS, respectively. Experimental results show that content of Cr(VI) increases gradually with the increase of temperature from 300 °C to 500 °C and reaches a maximal level of 46% total Cr at 500 °C, with different Cr(VI) species of CaCrO4, MgCrO4 and Cr5O12. However, the content of Cr(VI) decreases gradually with the further increase of temperature, with only about 5% Cr(VI) at high temperature of 1200 °C, due to formation of Cr(III) species of Cr2O3 crystallite and MgCr2O4 spinel. Besides, a growing number of hexagonally shaped flake-like crystallite Cr2O3 can be discovered from characterization results of XRD and SEM. Finally, the reduction of CaCrO4 to Cr2O3 in the presence of SiO2 is thermodynamically feasible over 700 °C, indicating possible transformation of Cr(VI) to Cr(III) through controlled incineration temperature.

In this paper, a process combining biodegradation and Fenton oxidation was proposed for the removal of polydiallyldimethylammonium chloride-acrylic-acrylamide-hydroxyethyl acrylate (PDM) in aqueous phase. Biodegradation of PDM was investigated in activated sludge systems, and the effects of the solution pH, mixed liquid suspended solids (MLSS), salinity, co-substrate, and initial substrate concentration, were studied. The biodegradation process was well-described with the Monod model and the values of the kinetics parameters vmax, ks were 0.05 h−1 and 333 mg/L. The optimal biodegradation conditions in the experimental range were determined to be: pH = 7.0, 0%–0.01% (w/v) NaCl, 4000 mg/L of MLSS, and 500 mg/L of glucose as co-substrate. FT-IR analysis indicated that PDM molecules biodegradation partly. The microbial community structures and dehydrogenase activity analysis revealed that PDM showed some toxicity to microorganisms in activated sludge. The effects of several parameters, including the pH and chemical doses, were investigated for removing PDM in Fenton oxidation process. The optimal Fenton oxidation process conditions in the experimental range were pH = 2.0, Fe2+ concentration of 40 mg/L, and H2O2 dosage of 23 mL/L. PDM was treated by biodegradation and subsequent Fenton oxidation under the optimal operating conditions. The removal efficiency was 44.5% after the biodegradation process and further increased to 85.5% after Fenton oxidation. The combined process was revealed to be a promising solution for achieving effective and economical removal of PDM.

Extensive usage of different kinds of lithium ion batteries (LIBs) may result in a huge amount of complicated waste batteries stream, while insufficient attention has been paid on the selective recovery of lithium from these already complicated wastes. Herein, a novel approach was developed for the selective extraction of Li from mixed types of LIBs (LiCoO2, LiMn2O4, LiFePO4 and LiCo1/3Mn1/3Ni1/3O2) using mild phosphoric acid as efficient leaching agent. It can be concluded from leaching results that 100%, 92.86%, 97.57% and 98.94% Li can be selectively extracted from waste cathode materials of LiCoO2, LiMn2O4, LiFePO4 and LiCo1/3Mn1/3Ni1/3O2, respectively, while transition metals (Co, Mn, Fe and Ni) can be hardly leached in mild acidic media under optimized leaching conditions. In addition, high selectivity coefficients (βLi/Me) can be obtained during the extraction of Li from other metals. It can be also discovered from characterization results (SEM, XRD, FT-IR and Raman spectra) that leaching residues are phosphate precipitates, which might be used for the recycling of other metals and preparation of cathode materials. Results from leaching kinetics indicate that the leaching of Li is chemical and internal diffusion controlled reaction, with apparent activation energy (Ea) of 37.74, 21.16, 27.47 and 21.86 kJ/mol for LiCoO2, LiMn2O4, LiFePO4 and LiCo1/3Mn1/3Ni1/3O2, respectively. Finally, lithium phosphate with a purity of 98.4% can be obtained and the whole process can be efficient candidate for Li recovery with minor environmental impact and little waste produced.

The treatment of a real wastewater characterized by low conductivity was performed by anodic oxidation at boron doped diamond (BDD) in both conventional and microfluidic cells. The electrolyses carried out in conventional cells without supporting electrolyte were characterized by very high TOC removals but excessively high energetic consumptions and operating costs. The addition of sodium sulphate, as supporting electrolyte, allowed to strongly reduce the cell potentials and consequently the energetic consumptions and the operating costs. However, under various operating conditions, the addition of Na2SO4 caused a lower removal of the TOC. The best results in terms of both TOC removal, energetic consumptions and operating costs (about 1 €/m3) were obtained using a cell with a very low inter-electrode distance (50 µm) with no addition of a supporting electrolyte.

Adsorptive studies were carried out on four synthetic vinyl polymer tanning agents removal from aqueous phase onto wastewater activated sludge (AS). Batch experiments investigated the effects of contact time, dosage of adsorbate, extracellular polymeric substances (EPS), coexisted cations, and physical property of sludge flocs on the four vinyl polymers removal by AS to evaluate the kinetics, isotherms, and mechanisms. Almost 96% of polydiallyldimethylammonium chloride-acrylic-acrylamide (PDM-AA-AM), 90% of polydiallyldimethylammonium chloride-acrylic (PDM-AA), 82% of polydiallyldimethylammonium chloride-acrylic-acrylamide-hydroxyethyl acrylate (PDM-AA-AM-HEA), and 56% of polydiallyldimethylammonium chloride (PDM) were removed from aqueous solutions. The kinetics process of adsorption can be described by the pseudo-second-order kinetic equation and the adsorption isotherms fitted to the Langmuir model very well. The adsorption capacity increases with the increase in initial vinyl polymers concentr...

Polyaniline/multiwalled carbon nanotube (PANI-MWCNT) was prepared by bounding polyaniline on the surface of oxidized multiwalled carbon nanotube. The structure and surface properties of synthesized composites were characterized by Fourier transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscope (TEM), and its adsorption capability for aqueous Cr(VI) was also studied. Characterized results showed that polyaniline was successfully anchored on the surface of MWCNT. From adsorption experiments the maximum adsorption amount of Cr(VI) onto PANI-MWCNTs was 28.25, 31.75 and 36.76 mg·g‒1 at 15, 25 and 35 °C. Thermodynamic parameters showed that the Cr(VI) adsorption process was endothermic, spontaneous and feasible. Cr(VI) adsorption followed pseudo-second-order kinetics. Cr(VI) adsorption on the adsorbent decreases with increasing solution pH. The presence of anions in solution almost has no effect on Cr(VI) adsorption, indicating good selectivity. XPS analysis confirms that electrostatic interaction, reduction and chelation contribute to enhanced Cr(VI) removal. Cr(VI) loaded absorbent can be readily desorbed in 0.1 mol·L‒1 of NaOH solution, and the desorption rate was 84.12%.

Biodegradation studies of polydiallyldimethylammonium chloride-acrylic-acrylamide-hydroxyethyl acrylate/ZnO (P(DMDAAC-AA-AM-HEA)/ZnO) nanocomposite were performed in a simulated aerobic activated sludge system. Batch experiments were conducted with different initial substrate concentrations between 100 and 1000 mg L−1 at pH 7 and 25 °C. The biodegradability tests of the samples by activated sludge exhibited significant degradation after 30 days of inoculation. The removal ratios were 71.8%, 67.1% and 63.6% at initial P(DMDAAC-AA-AM-HEA)/ZnO concentrations of 100, 500, and 1000 mg L−1, respectively, indicating that the biodegradation efficiency decreased with increasing initial substrate concentration. Kinetic studies showed that the Monod model could accurately describe the biodegradation process. The estimated values of the maximum specific rate of substrate degradation (νmax) and saturation rate constant (ks) were 2.56 h−1 and 336 mg L−1, respectively. The biodegradability of the P(DMDAAC-AA-AM-HEA)/ZnO nanocomposite was further confirmed through dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC) analysis. The action of microorganisms in the activated sludge caused the partial disruption of nano ZnO-matrix bonding, and was followed by random chain scission in the P(DMDAAC-AA-AM-HEA) polymer chains. These changes were accompanied by significant losses in the concentration and molecular weight of the samples.

BACKGROUND Mac-2 binding protein (M2BP) is an inflammatory glycoprotein associated with carotid atherosclerosis and all-cause mortality in patients with suspected coronary artery diseases. We aimed to explore the potential association of plasma M2BP levels with unstable plaque morphology and cardiovascular outcomes in patients with acute coronary syndrome (ACS). PATIENTS AND METHODS We compared plasma M2BP levels among three groups: 216 patients with ACS, 82 patients with stable angina pectoris, and 50 controls. Angiographic analyses of complex lesions were carried out in patients with ACS and they were followed up prospectively for 12 months for the occurrence of major adverse cardiovascular outcomes (MACEs). RESULTS Patients with ACS showed significantly higher plasma levels of M2BP than patients with stable angina pectoris (P

Various organic compounds extensively used in the leather industry could influence the performance of alkaline precipitation with Cr(III). This study focused on two typical Cr(III)-bearing complexes (Cr(III)-collagen and Cr(III)-citrate) ubiquitous in tannery effluent yet with distinct treatment efficiencies, as Cr(III) was much more difficult to remove in the Cr(III)-citrate solution. Comprehensive analytical methods were employed to explore the intrinsic mechanism. It was found that a lower removal efficiency towards Cr(III) was significantly associated with higher oligomers. The molecular size of the Cr(III)-citrate complex continued to increase with rising pH, making it larger overall than Cr(III)-collagen species. The growing oligomer moiety of dissolved Cr(III)-complex species could persist in the stronger basic pH range, leading to the large amount of residual Cr(III) in the Cr(III)-citrate system. Combining this result with potentiometric titration and X-ray photoelectron spectroscopy data, it was believed that the polymeric species other than monomers facilitated resisting the attack from hydroxide ions, and the postulated Cr(III)-citrate species towards higher oligomers were discovered. Beyond that, both charge neutralization and sweeping effects were presented among the gradually emerging flocs in the Cr(III)-collagen system together with the electric double layer compression effect derived from salinity, thus resulting in a larger floc size and higher Cr(III) removal efficiency in saline solutions.

The application or disposal of char derived from tannery sludge is directly influenced by the mobility and bioavailability of Cr during pyrolysis process. This study focused on the changes of Cr speciation and organic matter in tannery sludge during low-temperature pyrolysis (100–400 °C) to evaluate the toxicity of char in terms of the leaching possibility of Cr. The results showed that (1) lower char yield and more porous structure were observed after pyrolysis. (2) Higher pyrolysis temperature increased Cr content in the char; however, Cr in this case was converted into the residual fraction which minimized its bioavailability therefore lowers its potential risk to the environment. (3) Organic matters in the acid and alkali leachates were mainly humic acid-like substance, and condensed organic matter might appear at 200 °C and then destruct. (4) Despite the comparatively high content of Cr in the char, the leaching toxicity of char was within the security range according to the national standard of China. The Cr content in the acid and alkali leachates decreased to the range of 16.5–35.3 and 0.2–6.8 mg/L, respectively. It was suggested that the potential toxicity of tannery sludge from Cr could be reduced before utilization or disposal by pyrolysis, especially under 400 °C.

The removal of polyacrylate/nano-ZnO (PA/ZnO) from water by simultaneous biosorption and biodegradation was investigated using an activated sludge (AS) unit. About 90.9%, 93.2% and 95.1% of the total PA/ZnO was removed when the AS biomasses were 2.5, 5.0 and 10.0 g, respectively. The removal efficiency increases with the increase of initial AS concentration. More than 74.5% of the total PA/ZnO was removed in the first day, implying that biosorption was the dominant removal route. The adsorption process fitted well to the Langmuir model rather than Freundlich model. Kinetics data showed better correlation with pseudo-second order than pseudo-first order models. PA/ZnO also exhibited certain biodegradability in the activated sludge reactor. Biodegradation mechanisms of PA/ZnO were studied by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and gel permeation chromatography (GPC). The results showed that the biodegradation process occurs in the AS microorganisms mainly though chain scission. Microbial community analysis by 16S rRNA based PCR-DGGE revealed little shift in the community structure and diversity, suggesting that PA/ZnO exhibits little toxicity to microorganisms.

Hexavalent chromium in aqueous environment may result in severe environmental and public health problems. In this study, short-chain polyaniline/palygorskite composites (PANI/PA) were prepared and developed to remove aqueous Cr(VI). Characterized results showed that short-chain polyaniline was successfully incorporated on the surface of PA. The maximum Cr(VI) adsorption amount was found to be 11.54, 14.34, and 16.22 mg/g at 15, 25, and 35°C, respectively, and polyaniline on the adsorbent surface may account for the enhanced Cr(VI) adsorption. Cr(VI) adsorption was highly dependent on both solution pH and ionic strength, which indicates that electrostatic force and anion exchange may account for the increased Cr(VI) adsorption onto PANI/PA. Cr(VI) saturated PANI/PA can be easily desorbed in alkaline solution and regenerated adsorbents still possess high adsorption amount for aqueous Cr(VI). The current study shows that PANI/PA can be used as an effective and recyclable adsorbent for the removal of ...

In this study, the removal potential of vinyl polymer/ZnO nanocomposite (PDM/ZnO) by activated sludge (AS) biomass was investigated. PDM/ZnO was effectively removed by AS adsorption (90.3% of total PDM/ZnO removed). The effects of contact time, temperature, pH of the solution, PDM/ZnO production method, initial adsorbate concentration, and properties of the adsorbent were studied. The experimental results are fitted with the Langmuir and Freundlich equations. The adsorption kinetics closely followed the pseudo-second-order model. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) indicate that the adsorption of PDM/ZnO onto AS was feasible, spontaneous, and endothermic. The effects of PDM/ZnO production method and pH value both indicate that electrostatic force may main mechanism in PDM/ZnO adsorption process. The decrease in the adsorption capacity of inactivated sludge suggests that the increase of adsorbent surface area also plays a significant role in the removal process.

Effective arsenic removal from highly laden industrial wastewater is an important but challenging task. Here, a combined coprecipitation/nano-adsorption process, with ferric chloride and calcium chloride as coprecipitation agents and polymer-based nanocomposite as selective adsorbent, has been validated for arsenic removal from tungsten-smelting wastewater. On the basis of operating optimization, a binary FeCl3 (520 mg/L)–CaCl2 (300 mg/L) coprecipitation agent could remove more than 93 % arsenic from the wastewater. The resulting precipitate has proved environmental safety based on leaching toxicity test. Fixed-bed column packed with zirconium or ferric-oxide-loaded nanocomposite was employed for further elimination of arsenic in coprecipitated effluent, resulting in a significant decrease of arsenic (from 0.96 to less than 0.5 mg/L). The working capacity of zirconium-loaded nanocomposite was 220 bed volumes per run, much higher than that of ferric-loaded nanocomposite (40 bed volumes per run). The exhausted zirconium-loaded nanocomposite could be efficiently in situ regenerated with a binary NaOH–NaCl solution for reuse without any significant capacity loss. The results validated the combinational coprecipitation/nano-adsorption process to be a potential alternative for effective arsenic removal from highly laden industrial effluent.

Polymer nanocomposites have been widely used in the preparation of coating agents in the leather industry. Considering the complex bio-effect and ecological risk of nanomaterial, research on the biodegradability and biocompatibility of polyacrylate/metal nanocomposites in activated sludge system is of specific significance. We investigated the change of the bacterial community and diversity of activated sludge fed with polyacrylate/ZnO nanocomposites in both low (500 mg COD /L) and high (1000 mg COD/L) doses. COD removal, dehydrogenase activity, and total protein of activated sludge system were monitored in all treatments over 30 days. The results demonstrated that the exposure to both polyacrylate/ ZnO nanocomposite and polyacrylate decreased the dehydrogenase activity at early stage comparing to the control, but had no significant influence on COD removal. Overall, the bacterial communities in activated sludge were resistant to polyacrylate/ZnO nanocomposites, and had higher levels of metabolic activity, protein accumulation and bioavailability when exposed to these chemicals comparing to the control especially at later stages of incubation (15-30 days), which indicated that these polyacrylate/ZnO nanocomposites of certain amount were biocompatible to activated sludge system.

The potential carbon sequestration ability of biochar was investigated. The results indicated the amendment of biochar to soil could reduce the CO2 emission and increase the organic matter of soil effectively. The influence extent enhanced as the increase of biochar and the influence extent on soil with lower organic matter content is much obvious than soil with higher organic matter content. After incubated 7 months, soil CO2 emission was suppressed significantly by the amendment of biochar. The CO2 release amount in soils with 8% biochar decreased 29%∼39% compared with control. Organic matter content in soils with 8% biochar increased 41%∼75%. In addition, biochar promoted the formation of soil aggregates. Mean weight diameter of micro-aggregates in soils with biochar increased obviously compared with the control, indicating that stability of soil aggregates improved as the increase of biochar. The research demonstrated that biochar had potential ability on soil carbon sequestration, which was realized by enhance organic matter content, suppressing CO2 release and improving micro-structure characteristic of soil. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 941–946, 2014

Tannic acid is generally considered as one of polyphenolic pollutants, which may cause severe threats to the environment. In this study, polyaniline adsorbent was synthesized by chemical oxidation to remove tannic acid in aqueous solutions. The adsorption amount of tannic acid varied greatly with pH of solution and strong adsorption was at pH 5.8–6.7. Coexisting cations, such as Na+, K+, and Ca2+, can enhance the adsorption of tannic acid on polyaniline, which may be contributed to the electrostatic interaction between tannic acid and polyaniline. The adsorption process could be well described by Langmuir model and the maximum adsorption capacity was 117.65 mg·g−1 at 35 °C and pH 6.0. The thermodynamic parameters calculated from the adsorption isotherms indicate that the adsorption of tannic acid is spontaneous and endothermic process. The polyaniline saturated with tannic acid can be desorbed in alkaline solution and regenerated adsorbent can be used repeatedly with high adsorption capacity, which implies that polyaniline adsorbents have a great potential in water purification for the removal of tannic acid.

A novel 5,15-di-[4-carboxylatomethoxy]phenyl-10,20-diphenylporphyrin, its copper complex and the corresponding metalloporphyrin-TiO2 photocatalyst were synthesized and characterized by DRS, SEM, XRD, and FT–IR. The photocatalytic effects of anataseTiO2 impregnated with this copper(II) porphyrin was investigated by photodegradation of 4-nitrophenol(4-NP) in aqueous solution under Xenon lamp irradiation. The results indicated that the photoactivity of copper(II) porphyrin-TiO2 composite was evidently enhanced by the interaction between carboxyl of the porphyrin molecule and hydroxyls anchored on the TiO2. Futhermore, the copper(II) carboxylic porphyrin displayed good adsorption behavior and activity of the dye-sensized TiO2 system.

Three azo dyes (Methyl Orange, Direct Brown and Direct Green) were treated by catalytic wet air oxidation (CWAO) with the catalysts CuO/γ-Al(2)O(3) prepared by consecutive impregnation. The relationship of decolorization extent, chemical oxygen demand (COD) removal extent and total organic carbon (TOC) in dye solution were investigated. The results indicated that the CuO/γ-Al(2)O(3) catalyst had excellent catalytic activity in treating azo dyes. Almost 99% of color and 70% of TOC were removed in 2h. The high removal extent of color and TOC indicated that the CWAO obtained perfect decomposition for pollutants. The degradation pathway of azo dyes was analyzed by UV-Vis, FTIR and MS. According to the examined results, the hydroxyl ((·)OH) radicals induced strong oxidizing effects in the target solution and destroyed the chromophoric groups of azo-benzene conjugated of the molecular structure. Considering characteristics of the dye structure, the azo bond (-N=N-) would first be attacked by the hydroxyl radical and other free radicals. With the continuous oxidization and the long reaction time at high temperature, these intermediates could be oxidized to the final oxidation products, such as water and carbon dioxide.

Global temperature rise over the long term will be proportional to the total amount of CO2 emitted. Any given probability of exceeding a targeted maximum temperature rise implies a maximum limit on the cumulative total of CO2 that can be emitted: a CO2 “budget”. This paper describes an approach to modelling cumulative emissions from light and heavy duty road transport from the present to 2050, focussing on the USA and Europe, and comparing the potential impacts of a range of technological and behaviourally-based abatement measures with such cumulative emissions budgets. The model shows that abatement measures would have a lower effect on cumulative emissions from 2000 to 2050 than on annual emissions in 2050, so that focussing only on annual emissions could be misleading. It shows that technological developments would be insufficient on their own to enable Europe and the USA to meet CO2 budgets for road transport. Behavioural changes, which potentially can be implemented much sooner, would be essential too. There is potential to keep European light duty emissions very close to CO2 budgets, and US light duty emissions not far above the least restrictive budget, but the model predicts that heavy duty emissions in both regions are likely to exceed their CO2 budgets. Deeper emissions reductions in other regions and sectors will be needed to compensate for this. Timing would be critical: for the greatest impact, behaviour change policies and interventions would need to be applied early and deeply.

This paper first presents an exposition of the theory relevant to quantitative planar laser-induced fluorescence measurements in an engine, at a level commensurate with the expertise of a specialist engineer. It is intended to provide a grounding in the technique, its theoretical basis, and a source of references. Second, this paper presents the design of a multi-component fuel and fuel tracer set that may be used for quantitative planar laser-induced fluoroscence (PLIF) where time and crank-angle resolved knowledge of the vaporization of different fuel fractions is required. Such a fuel is presented and shown to exceed the specifications of accepted single-component fuel tracers. The fuel distillation characteristics, construction, and key features are discussed in the context of the theory.

It is difficult to completely remove Cr(III) from tannery effluent by alkaline precipitation due to the abundance of strong organic ligands. Thereby, the speciation of the residual Cr after alkaline precipitation is of crucial significance to guide the selection and design of further treatment process. For the first time, we revealed the speciation of the residual Cr with the aid of comprehensive analytical techniques. Results showed that the residual Cr(III) mostly located in two size ranges, i.e. the 13-100nm fraction and the4nm fraction. Combined spectral analyses demonstrated Cr(III) was coordinated by carboxyl groups or hydroxyl groups in both fractions, while the complexation by nitrogen-containing groups was excluded by the total nitrogen and UPLC-MS analysis in the two fractions, respectively. Based on the comprehensive analyses, the structures of Cr(III) complexes in both fractions were proposed. Cr(III) cross-linked the carboxyl groups from polyacrylic acid chains to form the network gel structure in the 13-100nm fraction, while the complex structure of Cr(III) in the4nm fraction was formed through hydroxyl-carboxyl chelation by masking agents such as tartrate and citrate. Although polyoxyethylene ether was abundantly present, it was responsible for the complexation of Cr(III) in neither fraction.

This paper investigates the well-to-wake energy consumption and greenhouse gas emissions of several key SO X abatement options in marine transportation, ranging from the manufacture of low sulfur fuels to equipping the vessel with suitable scrubber solutions. The findings suggest that a scrubber system, used with current heavy fuel oils, has the potential to reduce SO X emissions with lower well-to-wake energy consumption and greenhouse gas emissions than switching to production of low sulfur fuels at the refinery. A sensitivity analysis covering a series of system parameters shows that variations in the well-to-tank greenhouse gas emissions intensity and the energy efficiency of the main engine have the highest impacts in terms of well-to-wake emissions.

Electric vehicles have recently been gaining increasing worldwide interest as a promising potential long-term solution to sustainable personal mobility; in particular, battery electric vehicles (BEVs ) offer zero tailpipe emissions. However, their true ability to contribute to greenhouse gas (GHG) emissions reductions can only be properly assessed by comparing a life cycle assessment of their GHG emissions with a similar assessment for conventional internal combustion vehicles (ICVs). This paper presents an analysis for vehicles typically expected to be introduced in 2015 in two example markets (the UK and California), taking into account the impact of three important factors: • Like-for-like vehicle comparison and effect of real-world driving conditions. • Accounting for the GHG emissions associated with meeting the additional electricity demand for charging the batteries. • GHG emissions associated with vehicle manufacture, disposal, etc. This work demonstrates that all of these factors are important and emphasises that it is therefore crucial to clearly define the context when presenting conclusions about the relative GHG performance of BEVs and ICVs – such relative performance depends on a wide range of factors, including the marginal regional grid GHG intensity, vehicle size, driving pattern, loading, etc.

Polyaniline adsorbent prepared by chemical oxidation was developed to remove the humic acid (HA) in aqueous solution. The adsorbents showed the high adsorption capacity for aqueous HA with the maximum adsorption amount 126.58 mg g−1, and the adsorption isotherm obeyed the Langmuir model. The adsorption kinetics followed an initial diffusion-controlled and then an attachment-controlled adsorption process. The HA adsorption was not much impacted in the presence of Na+, K+, while Ca2+ ion in aqueous solution can evidently enhance the HA adsorption. The HA adsorption on polyaniline decreased with increasing solution pH owing to the electrostatic interaction between imine and amine of polyaniline and disassociated HA. The HA molecules adsorbed on the polyaniline can be effectively desorbed in 0.1 M NaOH solution, and regenerated adsorbent can be repeatedly used in the subsequently adsorption–regeneration cycles.

Polyaniline/attapulgite composite (ATP–PANI) was prepared by in situ chemical oxidation and characterized by FITR, XRD, and TEM. Characterized results showed that polyaniline (PANI) was successfully encapsulated on the surface of attapulgite (ATP). Humic acid (HA) adsorption onto ATP–PANI was investigated by batch experiments and adsorption kinetic tests. In contrast with the low HA adsorption amount on ATP, substantially enhanced HA adsorption onto ATP–PANI was observed. Adsorption isotherms of HA can be well described by Langmuir model and the maximum adsorption amounts were found to be 43.01, 52.91, 61.35 mg/g at 15, 25, and 35 °C, respectively. HA adsorption increased with rise in temperature indicating of an endothermic process of HA adsorption onto ATP–PANI. Pseudo-second order kinetic equation can fit HA adsorption very well and the adsorption rate decreased with increasing initial HA concentration. HA adsorption decreased monotonously with increasing solution pH. Co-existed cations (Na + , K + , Ca 2+ ) in aqueous solution improved HA adsorption amount on ATP–PANI, and the augment of HA adsorption amount was order as Ca 2+ > K + > Na + . Results of HA adsorption onto ATP–PANI showed that the electrostatic interaction between amine and imine groups of the adsorbents and HA molecules in solution may account for the enhanced HA adsorption. The HA molecules adsorbed on ATP–PANI can be effectively desorbed in 2 M NaOH solution, and regenerated adsorbent can be repeatedly used in the subsequently four adsorption-regeneration cycles with little loss of HA adsorption amount.