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The novel Ba0.15Sr0.85M0.15Fe0.85O3-δ (M = Fe, Co, Al, Ti) perovskite-type oxides were synthesized by the solid-state reaction method. Structural, sintering, and oxygen sorption/desorption properties of the as-synthesized Ba0.15Sr0.85M0.15Fe0.85O3-δ (M = Fe, Co, Al, Ti) perovskite-type oxides were studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry (TG). The electrical conductivities of the perovskite-type Ba0.15Sr0.85M0.15Fe0.85O3-δ (M = Fe, Co, Al, Ti) oxide ceramics were also measured at 300–925 °C in air, showing that the electrical conductivities were increased as the order M = Co > Fe > Al > Ti for the perovskite-type Ba0.15Sr0.85M0.15Fe0.85O3-δ oxides. The oxygen sorption/desorption properties of the perovskite-type Ba0.15Sr0.85M0.15Fe0.85O3-δ (M = Fe, Co, Al, Ti) oxides were investigated at 300–925 °C in air, and the oxygen sorption capacities of 18.9, 19.6, 18.2, 17.1 mL O2 (STP)/g oxide were obtained, respectively.

The present study reports a novel method for hydrogen generation and simultaneous removal of Cr(VI) from synthetic wastewater using NaBH

BACKGROUND SC79 has been reported to protect against experimental ischemia-elicited neuronal death and brain injury and to protect myocardiocytes from hypoxia/reoxygenation (H/R) injury. Here, we investigated the effects of SC79 in primary hepatocytes in vitro and in rat liver in vivo following hypoxia-reoxygenation (H/R) and hepatic I/R injury. MATERIAL AND METHODS The livers of Sprague-Dawley rats were subjected to 45 min of ischemia followed by 2-24 h of reperfusion. The primary hepatocytes were subjected to hypoxia for 6 h and for 2-24 h. The hepatocytes cells or the hepatic I/R injury model livers were treated with SC79 or/and LY294002 at different times and concentrations. The serum ALT, AST, histologic examination, cellular viability, and cell apoptosis were assessed. The levels of phospho-Akt, Bad, Bim, Bax, Bcl-2, and Bcl-XL were determined by Western blot analysis. RESULTS SC79 improved viability and inhibited apoptosis in hepatocytes following H/R. SC79 decreased serum AST and ALT, markedly improved pathology, and decreased cell apoptosis in livers following I/R. In addition, SC79 promoted the expression of phospho-Akt, Bcl-2, and Bcl-XL, and decreased the expression of Bid, Bax, and Bim. PI3K inhibitor (LY294002) pre-treatment completely abolished the above-mentioned effects of SC79. CONCLUSIONS The protective role of SC79 against H/R of hepatocytes or hepatic I/R injury is related to activation of phosphorylation of Akt, resulting in the decrease of pro-apoptotic protein of Bim, Bax, and Bad, and increase of the anti-apoptotic protein Bcl-2 and Bcl-xL induced by cell H/R and hepatic I/R injury.

Remediation of high concentrations of Cr(VI) in wastewater involves its chemical reduction to Cr(III), a product with low toxicity that can be easily removed. To date, NaBH4 has rarely been used to reduce Cr(VI). This article reports a comparative study of Cr(VI) removal by NaBH4 and five sulfur-based reducing agents (FeSO4, Na2S2O5, NaHSO3, Na2S2O3, and Na2SO3). The potential mechanisms of Cr(VI) removal by these six reducing agents with and without fly ash leachate (FAL) are also discussed. The results revealed that the reduction and subsequent removal of Cr(VI) are influenced by the hydrolysis and ionization of the reducing agents in solution. Thus, the reduction reaction was significantly enhanced when Na2S2O5 and NaHSO3 were added in excess of 600 mg L−1. Combined with FAL, smaller amounts of NaBH4 were required to reduce Cr(VI) to Cr(III) at pH 3.0 compared to those with the other reducing agents. NaBH4 combined with FAL at a dose of 100 mg L−1 afforded a total Cr (CrT) removal of 96.32% within 20 min, a value much higher than that obtained with the other reducing agents. The catalytic mechanism of NaBH4 for such a FAL-catalyzed Cr(VI) reduction system is similar to that of acid catalysis via the hydrolysis of the Fe(III) and Al(III) species in FAL. Improvement of the CrT removal was also observed via Cr(VI) entrapment in the structure of Fe(III) and Al(III) metal hydroxides. These results indicate that relatively low loadings of NaBH4 combined with FAL show great promise for Cr(VI) pollution remediation.

Background/Aims: Anaplastic thyroid cancer (ATC), with 25% BRAFV600E mutation, is one of the most lethal human malignancies that currently has no effective therapy. Vemurafenib, a BRAFV600E inhibitor, has shown promise in clinical trials, including ATC patients, but is being hampered by the acquisition of drug resistance. Therefore, combination therapy that includes BRAFV600E inhibition and avoids resistance is a clinical need. Methods: ATC cell lines 8505C (BRAFV600E/mt), SW1736 (BRAFV600E/mt), KAT18 (BRAFV600E/wt) and Cal-62(BRAFV600E/wt) cells were used in the study. The ability of S100A knockout or /and in combination with the BRAF inhibitor vemurafenib on growth, apoptosis, invasion and apoptosis in ATC cells in vitro was demonstrated by MTT and BrdUrd incorporation assay, Annexin-V-FITC staining analyzed by flow cytometry, Transwell migration and Matrigel invasion assay. S100A4,pERK1/2, pAKT and pROCK1/2 protein was detected by western blot assay; Small molecule inhibitors of Y27632, U0126, MK-2206 and constitutively active forms of pCDNA-Myc-pERK, pCMV6-HA-Akt, pCMV-RhoA were employed, and the mechanistic studies were performed. We assessed the efficiency of in vivo combination treatment with S100A4 knockout and Vemurafenib on tumors. Results: S100A4 knockout induced apoptosis and reduced proliferation by inactivation of pAKT and pERK signals, and inhibited invasion and migration by inactivation of pAKT and RhoA/ROCK1/2 signals in 8505C or Cal-62 cells in vitro, and vice versa in SW1736 and KAT18 cells. Vemurafenib did not affect apoptosis of both 8505C and SW1736 cells, but reduced proliferation via arresting cell cycle, and promoted cell migration and invasion in vitro. Combination treatment with S100A4 knockdown and vemurafenib reduced cell proliferation, migration and invasion in vitro compared to the S100A4 knockdown or Vemurafenib alone. Vemurafenib treatment resulted in a transient inhibition of pERK expression and gradually activation of pAKT expression, but quickly recovery from ERK1/2 activation inhibition by vemurafenib treatment in 4 h for SW1736 and 8505C cells. Combined treatment completely inhibited ERK1/2 and AKT activation during 48 h. In an in vivo mouse model of SW1736 and 8505C, vemurafenib treatment alone did not significantly inhibit tumor growth in both of the tumors, but inhibited tumor growth in combined groups. Conclusion: Our results show S100A4 knockout alone inhibits ATC cells (rich endogenous S100A4) survival and invasion, regardless of the BRAFV600E status, and potentiates the effect of vemurafenib on tumor regression in vitro and in vivo. In addition, S100A4 knockout potently inhibits the recovery from ERK1/2 activation inhibition and the AKT activation following vemurafenib treatment and reversed the vemurafenib resistance. This therapeutic combination may be of benefit in patients with ATC.

BACKGROUND [i]BRAF[/i]V600E mutation occurs in approximately 45% of papillary thyroid cancer (PTC) cases, and 25% of anaplastic thyroid cancer (ATC) cases. Vemurafenib/PLX4032, a selective BRAF inhibitor, suppresses extracellular signal-regulated kinase kinase/extracellular signal-regulated kinase 1/2 (MEK/ERK1/2) signaling and shows beneficial effects in patients with metastatic melanoma harboring the [i]BRAFV600E[/i] mutation. However, the response to vemurafenib is limited in BRAF-mutant thyroid cancer. The present study evaluated the effect of vemurafenib in combination with the selective MEK1/2 inhibitor AZD6244 on cell survival and explored the mechanism underlying the combined effect of vemurafenib and AZD6244 on thyroid cancer cells harboring BRAFV600E. MATERIAL AND METHODS Thyroid cancer 8505C and BCPAP cells harboring the [i]BRAFV600E[/i] mutation were exposed to vemurafenib (0.01, 0.1, and 1 µM) and AZD6244 (0.01, 0.1, and 1 µM) alone or in the indicated combinations for the indicated times. Cell viability was detected by the MTT assay. Cell cycle distribution and induction of apoptosis were detected by flow cytometry. The expression of cyclin D1, P27, (P)-ERK1/2 was evaluated by Western blotting. The effect of vemurafenib or AZD6244 or their combination on the growth of 8505C cells was examined in orthotopic xenograft mouse models [i]in vivo[/i]. RESULTS Vemurafenib alone did not increase cell apoptosis, whereas it decreased cell viability by promoting cell cycle arrest in BCPAP and 8505C cells. AZD6244 alone increased cell apoptosis by inducing cell cycle arrest in BCPAP and 8505C cells. Combination treatment with AZD6244 and vemurafenib significantly decreased cell viability and increased apoptosis in both BCPAP and 8505C cells compared with the effects of each drug alone. AZD6244 alone abolished phospho-ERK1/2 (pERK1/2) expression at 48 h, whereas vemurafenib alone downregulated pERK1/2 at 4-6 h, with rapid recovery of expression, reaching the highest level at 24-48 h. Combined treatment for 48 h completely inhibited pERK1/2 expression. Combination treatment with vemurafenib and AZD6244 inhibited cell growth and induced apoptosis by causing cell-cycle arrest, with the corresponding changes in the expression of the cell cycle regulators p27Kip1 and cyclin D1. Co-administration of vemurafenib and AZD6244 [i]in vivo[/i] had a significant synergistic antitumor effect in a nude mouse model. CONCLUSIONS Vemurafenib activated pERK1/2 and induced vemurafenib resistance in thyroid cancer cells. Combination treatment with vemurafenib and AZD6244 inhibited ERK signaling and caused cell cycle arrest, resulting in cell growth inhibition. Combination treatment in patients with thyroid cancer harboring the [i]BRAFV600E[/i] mutation may overcome vemurafenib resistance and enhance the therapeutic effect.

We in our previous study reported the wireless electrocoagulation (WEC) based on bipolar electrochemistry for water purification. One of the most important advantages of WEC is the omission of ohmic connection between bipolar electrode (BPE) and power supply, and thus the electrochemical reactions on BPE are driven by electric field in solution induced by driving electrodes. In this study, the impact of placement angle of bipolar aluminum electrode on WEC was investigated to provide a detailed analysis on the correlations between the bipolar electrode placement angle and bipolar electrocoagulation reactions. The results showed that the WEC cell with a horizontal BPE placed at 0° produced the maximum dissolved aluminum coagulant, accounting for 71.6 % higher than that with a vertical one placed at 90°. Moreover, the finite element simulations of current and potential distribution were carried out along the surface of BPE at different placement angles, revealing the mechanism of different BPE placement angles on aluminum dissolution rates in WEC system.

Melanoma treatment with the BRAF V600E inhibitor vemurafenib provides therapeutic benefits, but the common emergence of drug resistance remains a challenge. To define molecular mechanisms of vemurafenib resistance, we generated A375-R, WM35-R cell lines resistant to vemurafenib and found that the p-STAT3 was upregulated in these cells in vitro and in vivo. In particular, activation of the STAT3 pathway was associated with vemurafenib resistance. Inhibition of this pathway with STAT3-specific siRNA (shRNA) sensitized A375-R, WM35-R cells to vemurafenib and induced apoptosis in vitro and in vivo. Moreover, targeting STAT3 induced expression of miR-579-3p and elicited resistance to vemurafenib. However, targeting miR-579-3p with anti- miR-579-3p reversed the resistance to vemurafenib. Together, these results indicate that STAT3-mediated downexpression of miR-579-3p caused resistance to vemurafenib. Our findings suggest novel approaches to overcome resistance to vemurafenib by combining vemurafenib with STAT3 silencing or miR-579-3p overexpression.

Background/Aims: Cisplatin-based treatment is first-line chemotherapy for several cancers including ovarian cancer. The development of cisplatin resistance results in treatment failure, but the underlying mechanisms are not fully understood. Histone deacetylases (HDACs) are a large family of enzymes that deacetylate lysine residues on histones and non-histone proteins. High expression of HDAC1 is associated with poor outcomes in ovarian cancer. Furthermore, resistance to chemotherapeutic agents is associated with HDAC1 overexpression in ovarian cancer cells. The goals of this study were to determine whether targeting HDAC1 can sensitize ovarian cancer cells to cisplatin and to explore the underlying mechanisms. Methods: Small interfering RNA (siRNA)-targeting HDAC1 was designed to silence HDAC1 in the cisplatin-resistant ovarian cancer cell line A2780CDDP and its cisplatin-sensitive cell line A2780. The effects of targeting HDAC1 on cell viability assay, colony formation, and apoptosis were detected. c-Myc re-expression or miR-34a inhibitors were used to examine the relationship among HDAC1, c-Myc, and miR-34a expression, which was assessed by western blot analysis and quantitative reverse transcription PCR. We established stable transfectants of A2780CDDP/HDAC1 short hairpin RNA (shRNA) and A2780/HDAC1 shRNA. The therapeutic effectiveness of cisplatin in murine xenograft models was assessed following shRNA-mediated HDAC1 silencing in A2780CDDP and A2780 cells. The mechanism of cell death was studied in tumor sections obtained from different mouse tumors. Results: In cisplatin-resistant A2780CDDP cells, HDAC1 knockdown by siRNA suppressed cell proliferation, and increased apoptosis and chemosensitivity by downregulating c-Myc and upregulating miR-34a. In cisplatin-sensitive A2780 cells, HDAC1 knockdown did not affect cell proliferation and apoptosis. Cisplatin treatment activated HDAC1 and c-Myc and inactivated miR-34a. Inhibition of HDAC1 with siRNA reduced c-Myc expression, increased miR-34a expression, and sensitized A2780 cells to cisplatin-induced apoptosis. c-Myc re-expression or miR-34a targeting by miR-34a inhibitors protected cells from apoptosis or reversed cisplatin resistance following HDAC1 knockdown or/and cisplatin exposure. Finally, in vivo studies showed that targeting HDAC1 inhibited A2780CDDP-induced xenograft tumor growth but not A2780-induced xenograft tumor growth. Targeting HDAC1 sensitized both A2780- and A2780CDDP-induced xenograft tumors to cisplatin treatment. Conclusions: Upregulation of HDAC1 is a crucial event in the development of drug resistance to current treatments in ovarian cancer. Thus, targeting HDAC1 by enhancing c-Myc-dependent miR-34a expression might be an effective strategy for increasing the efficacy of cisplatin treatment.

Interface properties are crucial to anodic extracellular electron transfer (EET) and power production of microbial fuel cells (MFCs), because they determine the local density of electroactive biofilms and the efficiency of electron transfer. To enhance MFC performance by improving EET, a 3D-structured pseudocapacitive interface is created by in situ deposition of MnO2 on a carbon electrode through the redox reaction between permanganate and carbon. The electrochemical performance of the MnO2-modified carbon paper electrode is increased considerably compared with an unmodified electrode, due to the increased local density of the exoelectrogenic biofilm and effective interfacial shuttling of electrons facilitated by the pseudocapacitive MnO2. The process for constructing 3D MnO2-based interfaces is technologically simple, environmentally friendly, and cost-effective. This study provides a new and promising strategy for improving power production in MFCs for scaled-up applications.

4-Chloronitrobenzene (4-CNB) is one of the highly toxic contaminants that may lead to acute, chronic or persistent physiological toxicity to ecology and environment. Conventional methods for removing 4-CNB from aquatic environment may be problematic due to inefficiency, high cost and low sustainability. This study develops a pilot-scale bioelectrochemical system (BES, effective volume of 18 L) and examines its performance of bioelectrochemical transformation of 4-CNB to 4-chloroaniline (4-CAN) under continuous operation. The results demonstrate that the initial 4-CNB concentration in the influent and hydraulic retention time (HRT) has a significant impact on 4-CNB reduction and 4-CAN formation. Compared with the conventional anaerobic process in the absence of external power supplied, the 4-CNB conversion efficiency can be enhanced with power supplied due to microbial-mediated electron transfer at the negative cathode potential. At a voltage of 0.4 V and HRT of 48 h, the 4-CNB reduction and 4-CAN formation efficiency reached 99% and 94.1%, respectively. Based on a small external voltage applied, the pilot-scale BES is effective in the conversion of 4-CNB to 4-CAN, an intermediate that is of less toxicity and higher bioavailability for subsequent treatment. This study provides a new strategy and methods for eliminating 4-CNB, making wastewater treatment more economical and more sustainable.

The advanced oxidation process (AOP) based on SO

In this study, ethylenediamine tetraacetic acid (EDTA) was investigated as a new kind of non-polymeric catalyst binder to improve interfacial oxygen reduction reaction (ORR) for the cathode of microbial fuel cell (MFC). The electrochemical analysis and MFC tests show negative correlation between ORR activity and molar concentration of EDTA applied during electrode preparation. In particular, the 0.02mol/L-EDTA yields higher ORR activity than other binder materials like Nafion, water, 0.1mol/L-EDTA and 0.2mol/L-EDTA, as indicated by the strongest response of ORR current and the smallest charge-transfer resistance. Accordingly, the MFC with cathode of 0.02mol/L-EDTA produced a maximum power density of 722mW/m(2), accounting for a value approximately 42% higher than that of commercial Nafion binder (5wt%, 507mW/m(2)). The improved ORR activity should be attributed to the enhanced proton transfer from phosphate ions to EDTA-involved three-phase boundary as a result of dipole ion bonds on nitrogen atoms having unshared pair of electrons in EDTA molecule.

A surface modification strategy was applied by using 3-aminopropyltriethoxysilane (APTES) covalent linkage between the Schiff-base networks (SNW) polymer layers and porous α-Al2O3 ceramic support. The SNW-1 polymer membrane and powders resulting from the polycondensation reaction between melamine and terephthalaldehyde without the polycondensation catalysts were investigated by SEM and FT-IR. The results show that the discrete and few covered polymer layers were formed on the unmodified porous α-Al2O3 support. In contrast, the uniform and compact SNW-1 polymer membrane was fabricated successfully on the APTES modified α-Al2O3 support by in-situ catalyst-free polycondensation method, indicating that the APTES surface modification facilitates the growth of the novel SNW-1 polymer membrane on the porous α-Al2O3 support.

Dense relaxor ferroelectric 0.88Pb(Mg1/3Nb2/3)O3–0.12PbTiO3 (0.88PMN–0.12PT) ceramics with different La-doping contents (0, 1, 2 and 4 at.%) were sintered by using powders synthesized via a solid-state reaction route. The effects of La doping on the microstructures and electric properties of the 0.88PMN–0.12PT ceramics were investigated. It was found that the average grain size, remanent polarization Pr, coercive field Ec, Curie temperature Tc and leakage-current density J of the ferroelectric ceramics decrease significantly with increasing La doping content. The decrease in Pr, Ec and Tc can be understood in term of the fact that the substitution of Pb2+ ions by La3+ ions suppresses the long-range coupling of BO6 octahedrons, while the abatement in J can be explained according to the reduction of oxygen vacancies caused by La doping. By fitting the J–E curves, the conduction mechanism of the 0.88PMN–0.12PT ceramics is confirmed to be Ohmic conduction generated from oxygen vacancies. The dielectric and ferroelectric properties of 0.88PMN–0.12PT ceramics are tunable with manipulating the La doping content.

Forward osmosis (FO) represents a new promising membrane technology for liquid separation driven by the osmotic pressure of aqueous solution. Organic polymeric FO membranes are subject to severe internal concentration polarization due to asymmetric membrane structure, and low stability due to inherent chemical composition. To address these limitations, this study focuses on the development of a new kind of thin-film inorganic (TFI) membrane made of microporous silica xerogels immobilized onto a stainless steel mesh (SSM) substrate. The FO performances of the TFI membrane were evaluated upon a lab-scale cell-type FO reactor using deionized water as feed solution and sodium chloride (NaCl) as draw solution. The results demonstrated that the TFI membrane could achieve transmembrane water flux of 60.3 L m(-2) h(-1) driven by 2.0 mol L(-1) NaCl draw solution at ambient temperature. Meanwhile, its specific solute flux, i.e. the solute flux normalized by the water flux (0.19 g L(-1)), was 58.7% lower than that obained for a commercial cellulose triacetate (CTA) membrane (0.46 g L(-1)). The quasi-symmetry thin-film microporous structure of the silica membrane is responsible for low-level internal concentration polarization, and thus enhanced water flux during FO process. Moreover, the TFI membrne demonstrated a substantially improved stability in terms of mechanical strength, and resistance to thermal and chemical stimulation. This study not only provides a new method for fabricating quasi-symmetry thin-film inorganic silica membrane, but also suggests an effective strategy using this alternative membrane to achieve improved FO performances for scale-up applications.

BACKGROUND: Sustainable technologies need to be developed to treat saline seafood wastewater (SSW) efficiently. This study focused on the feasibility of a continuously operated microbial fuel cell (MFC) with modified anoxic/oxic (A/O) architecture (A/O–MFC) for power generation and treatment of SSW simultaneously. RESULTS: Hydraulic retention time (HRT) was shown to have an impact on polarization and power output of the A/O–MFC and the maximum power density of 16.2 W m−3 was obtained at a current density of 41.7 A m−3 and HRT of 4.2 h. High salinity together with advective flow mode enabled a low and constant internal resistance of approximately 100 Ω throughout the experiments. Besides, pH of waste stream in both compartments was found always near neutral level. Increasing HRT could improve eliminability of soluble chemical oxygen demand (sCOD) and biological nitrification. CONCLUSIONS: This study provides a proof-in-concept demonstration to utilize an MFC for effective and sustainable treatment of SSW along with recovery of electrical energy. Copyright © 2010 Society of Chemical Industry

A two-chambered microbial fuel cell (MFC) with potassium ferricyanide as its electron acceptor was utilized to degrade excess sewage sludge and to generate electricity. Stable electrical power was produced continuously during operation for 250 h. Total chemical oxygen demand (TCOD) of sludge was reduced by 46.4% when an initial TCOD was 10,850 mg/l. The MFC power output did not significantly depend on process parameters such as substrate concentration, cathode catholyte concentration, and anodic pH. However, the MFC produced power was in close correlation with the soluble chemical oxygen demand (SCOD) of sludge. Furthermore, ultrasonic pretreatment of sludge accelerated organic matter dissolution and, hence, TCOD removal rate in the MFC was increased, but power output was insignificantly enhanced. This study demonstrates that this MFC can generate electricity from sewage sludge over a wide range of process parameters.

Performance of biological phosphorus removal in the oxic-settling-anaerobic (OSA) process was investigated. Cell staining and fluorescent in situ hybridization (FISH) were used to analyze characteristics and microbial community of sludge. Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus (TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms (PAOs). FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria.

A microbial fuel cell using aerobic microorganisms as the cathodic catalysts is described. By using anaerobic sludge in the anode and aerobic sludge in the cathode as inocula, the microbial fuel cell could be started up after a short lag time of 9 days, generating a stable voltage of 0.324 V (R (ex) = 500 Omega). At an aeration rate of 300 ml min(-1) in the cathode, a maximum volumetric power density of up to 24.7 W m(-3) (117.2 A m(-3)) was reached. This research demonstrates an economic system for recovering electrical energy from organic compounds.

Sustainable electricity was generated from glucose in up-flow air-cathode microbial fuel cells (MFCs) with carbon cloth cathode and carbon granular anode. Plastic sieves rather than membrane were used to separate the anode and cathode. Based on 1g/l glucose as substrate, a maximum volumetric power density of 25+/-4 W/m(3) (89 A/m(3)) was obtained for the MFC with a sieve area of 30 cm(2) and 49+/-3 W/m(3) (215 A/m(3)) for the MFC with a sieve area of 60 cm(2). The increased power density with larger sieve area was mainly due to the decrease of internal resistance according to the electrochemistry impedance spectroscopy analysis. Increasing the sieve area from 30 cm(2) to 60 cm(2) resulted in a decrease of overall internal resistance from 41 ohm to 27.5 ohm and a decrease of ohmic resistance from 24.3 ohm to 14 ohm. While increasing operational recirculation ratio (RR) decreased internal resistance and increased power output at low substrate concentration, the effect of RR on cell performance was negligible at higher substrate concentration.

An air-cathode microbial fuel cell (MFC) is an efficient and sustainable MFC configuration for recovering electrical energy from organic substances. In this paper, we developed a graphite-granule anode, tubular air-cathode MFC (GTMFC) capable of continuous electricity generation from glucose-based substrates. This GTMFC produced a maximum volumetric power of 50.2 W m −3 at current density of 216 A m −3 ( R EX = 22 Ω). Electrochemistry impedance spectroscopy (EIS) measurements demonstrated an overall internal resistance of 27 Ω, consisting of ohmic resistance of R ohm = 13.8 Ω (51.1%), a charge-transfer resistance of R c = 6.1 Ω (22.6%) and a diffusion resistance of R d = 7.2 Ω (26.3%). Power generation with respect to initial chemical oxygen demand (COD) concentration was described well by an exponential saturation model. Recirculation was to found to have a significant effect on electrochemical performance at low COD concentrations, while such effect was absent at high COD concentrations. This study suggests a feasible and simple method to reduce internal resistance and improve power generation of sustainable air-cathode MFCs.

Irrigation with tertiary effluent, secondary effluent, and raw wastewater (sewage) were studied with tap water irrigation as the control. The effects of the irrigations on the qualities of three testing crops: cucumber, celery cabbage and maize were investigated. The contents of residual chloride ion, phosphate, nitrate, nitrite, and residual heavy metals in these irrigated crops were also examined. The results showed that the secondary and tertiary effluent had no significant effects on the crop qualities. However, irrigation with the sewage could lead to increase parts of nutrient components in the crops. Irrigation with the sewage caused accumulation of nitrate and heavy metals in the crops, indicating that sewage was not suitable for irrigation. The risk assessment results suggested that the health risk of the irrigations using sewage and secondary effluent exceeded the maximum acceptable risk level. Comparatively, the risk in the tertiary effluent irrigation was much lower than the acceptable level.

The microbial fuel cell (MFC) was proved to be a novel bioprocess capable of recovering electrical energy from organic matter. In this study, we report that by using permanganate as the cathodic electron acceptor for a MFC we were actually able to recover much more electrical power than using other existing types of electron acceptors, e.g. using permanganate as the cathodic electron acceptor for a two-chamber MFC generated a maximum power density of 115.60 mW m−2 which was, respectively, 4.5- and 11.3-fold higher than that produced by using hexacynoferrate (25.62 mW m−2) and oxygen (10.2 mW m−2) as the cathodic electron acceptor. This could be attributed to the higher open circuit potential (OCP) provided by permanganate in the MFC. Besides, pH, unlike permanganate concentration, was further found to have a major impact on the OCP and the cathode potential. SEM and XPS analysis demonstrated that manganese dioxide (MnO2) was in fact the main reduced product of the permanganate at pH 3.6. Moreover, as compared to a two-chamber MFC, a bushing MFC using permanganate as the cathodic electron acceptor achieved an unprecedented maximum power-output of 3986.72 mW m−2. This study for the first time showed that permanganate could be used as an effective cathodic electron acceptor for a MFC.

To develop efficient and cost-effective cathodic electrocatalyst for microbial fuel cell (MFC), this study investigates the feasibility of Pt–Fe alloy immobilized on carbon material for electrochemical oxygen reduction reaction (ORR). By performing cyclic voltammogram tests, the carbon supported Pt–Fe alloy (C/Pt–Fe) exhibited an improved catalytic activity toward ORR compared to both C/Fe and C/Pt catalyst. Based on 0.5 mg/cm2 Pt utilization, the maximum power density of 1097.6±51.2 mW/m2 produced from the MFC with C/Pt–Fe catalyst was 6.5% higher than that of 1030.4±47.8 mW/m2 obtained from the MFC using C/Pt catalyst. The Pt-based alloy proposed herein suggests a promising approach to efficient ORR of MFC, which makes it more technically and economically viable to recover electrical energy from biomass materials. Keywords: Pt–Fe alloy, Oxygen reduction reaction, Microbial fuel cell, Power density

A novel surface modification strategy was developed using 3-aminopropytriethoxysilane and 4-formylphenylboronic acid successively as covalent linkers between COF-5 and the porous α-Al2O3 ceramic support, and then the COF-5 membrane was further grown successfully on the modified α-Al2O3 support by using a microwave irradiation method.

To explore efficient and cost-effective cathode material for microbial fuel cells (MFCs), the present study fabricates a new type of binder-free gas diffusion electrode made of cobalt oxide (Co3O4) micro-particles directly grown on stainless steel mesh (SSM) by using an ammonia-evaporation-induced method. In various electrochemical analyses and evaluations in batch-fed dual-chamber MFCs, the SSM/Co3O4 hybrid electrode demonstrates improved performances in terms of electrocatalytic activity, selectivity, durability and economics toward oxygen reduction reaction (ORR) in pH-neutral solution, in comparison with conventional carbon supported platinum catalyst. This study suggests a new strategy to fabricate a more effective electrode for ORR in MFCs, making it more technically and economically viable to produce electrical energy from organic materials for practical applications.

This study reports the fabrication of a new membrane electrode assembly by using stainless steel mesh (SSM) as raw material and its effectiveness as gas diffusion electrode (GDE) for electrochemical oxygen reduction in microbial fuel cell (MFC). Based on feeding glucose (0.5 g L(-1)) substrate to a single-chambered MFC, power generation using SSM-based GDE was increased with the decrease of polytetrafluoroethylene (PTFE) content applied during fabrication, reaching the optimum power density of 951.6 mW m(-2) at 20% PTFE. Repeatable cell voltage of 0.51 V (external resistance of 400 Ω) and maximum power density of 951.6 mW m(-2) produced for the MFC with SSM-based GDE are comparable to that of 0.52 V and 972.6 mW m(-2), respectively obtained for the MFC containing typical carbon cloth (CC)-made GDE. Besides, Coulombic efficiency (CE) is found higher for GDE (SSM or CC) with membrane assembly than without, which results preliminarily from the mitigation of Coulombic loss being associated with oxygen diffusion and substrate crossover. This study demonstrates that with its good electrical conductivity and much lower cost, the SSM-made GDE suggests a promising alternative as efficient and more economically viable material to conventional typical carbon for power production from biomass in MFC.

Both ultrasonic and alkaline pretreatment of excess sewage sludge were investigated to enhance organic degradation and electricity generation from sludge by the subsequent microbial fuel cell (MFC). The ultrasonic pretreatment showed that the degree of sludge disintegration was directly related to the energy input, ultrasonic density and duration. Alkaline pretreatment demonstrated that more soluble organic matters were released from the sludge with more NaOH dose and longer reaction time, and the degree of sludge disintegration within 30 min accounted for 45–76% of that for 24 h. When ultrasonic and alkaline pretreatment were combined, the released chemical oxygen demand (COD) was higher than those with ultrasonic or alkaline pretreatment alone. Ultrasonic and alkaline (pH=11) pretreatment could enhance electricity generation from sludge by the subsequent MFC, resulting in more degradation of total COD (TCOD) and volatile solids (VS). Slight change in power output from the MFC was observed due to the higher soluble chemical oxygen demand (SCOD) in the pretreated sludge. By using the combined ultrasonic and alkaline pretreatment of sludge, the removal efficiencies of TCOD and VS were increased from 27.1% to 61.0% and 35.2% to 62.9% in comparison with raw sludge, respectively, and the power output in MFC was slightly increased from 10.3 W/m3 to 12.5 W/m3.