Hydrogen Production Ability Research Articles

Homogeneous precipitation and urea-nitrate combustion preparation of nanostructured CuO/CeO2/ZrO2/Al2O3 oxides used in hydrogen production from methanol for fuel cells

The urea-nitrate combustion and homogeneous precipitation methods have been comparatively examined for the preparation of CuO/CeO2/ZrO2/Al2O3 catalysts. Their physicochemical properties, as well as their hydrogen production ability via the steam reforming of methanol, have been studied. Prepared catalysts were characterized using XRD, FESEM, EDX, BET, and FTIR analyses. Characterization analyses and catalytic performance studies showed that the preparation method plays an important role in the synthesis of catalysts. XRD analysis showed that the homogeneous precipitation method can prepare catalyst with smaller copper crystallites and better surface dispersion compared with the combustion synthesis method. EDX results illustrated homogenous dispersion of elements. BET and FESEM showed the surface area improvement and lower size distribution, respectively, during synthesis of catalysts by the homogeneous precipitation method. Catalytic performance study also proved that catalyst prepared by the homogeneous precipitation method had better methanol conversion at all temperatures, whereas the sample fabricated by the urea-nitrate combustion synthesis method produces less CO. The stability test showed that the catalyst synthesized by the combustion synthesis method was quite stable for the steam reforming of methanol.

Self-assembly of zinc cadmium sulfide nanorods into nanoflowers with enhanced photocatalytic hydrogen production activity

ZnCdS solid solutions have been extensively studied due to their excellent photocatalytic hydrogen evolution performance. The change of the molar ratio of precursors affects the morphology and structure of ZnCdS, with the subsequent influence on the separation of photogenerated electron–hole pairs and the hydrogen production ability. The effect of the amount of nonmetallic elements on the photocatalytic activity has been scarcely explored. In this work, the morphology of ZnCdS is regulated by varying the amount of thioacetamide as S precursor. The structure of the samples is thoroughly analyzed by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis. Their optical properties, photocatalytic hydrogen evolution ability, and photoelectrochemical performance are evaluated. Upon increasing the amount of thioacetamide, the crystallinity improves, the ZnCdS nanorods self-assemble into nanoflowers, and the number of defects decreases. The highest photocatalytic activity is achieved for a (Zn + Cd):S molar ratio of 1:3.5. Moreover, the photocatalyst exhibits excellent stability after six cycles. The one-dimensional nanorod structure contributes to the formation of a space charge region that drives the charge carriers along the nanorods. The self-assembled ZnCdS nanoflowers provide extra channels for the charge transfer, improving the separation of electron–hole pairs.

The use of ferrites as highly active oxygen storage materials for chemical looping hydrogen production under intermediate temperature

Shifting chemical looping from high temperatures to intermediate temperatures could mitigate the materials from sintering and benefit for longer durability as well as process economy. However, oxygen carriers cannot perform sufficiently due to the degrading effect at lower temperatures, resulting in the decrease of hydrogen production ability. Although doping precious metals can improve the poor performance at intermediate temperatures, the high cost impeded their large-scale application. In this paper, a range of oxygen carrier materials consisted of earth abundant elements were prepared for chemical looping hydrogen production. The results indicated that CoFe2O4 exhibited the highest hydrogen yield of 11.9 mmol·g−1 and hydrogen production rate of 0.051 mmol g−1·s−1 at 650 °C, which was 1.7 times higher than that of Fe2O3. A combined experimental and DFT calculation method was used to understand the mechanism behind the performance. The results indicated that the synergistic effect between Co and Fe increased the reactivity of the ferrite materials. The enhanced hydrogen production performance was attributed to the high reduction degree and reversible phase change. This study can be also extended to develop more active oxygen carrier for chemical looping processes at intermediate temperatures.

Catalytic Steam Reforming of Biomass-Derived Acetic Acid over Two Supported Ni Catalysts for Hydrogen-Rich Syngas Production.

The catalytic steam reforming (CSR) of biomass-derived acetic acid over the commercial Ni-based catalyst (CNC) and the maize stalk ash-supported Ni catalyst (Ni/MSA) for hydrogen-rich syngas production was studied by means of a bench-scale fixed-bed unit combined with NDIR/TCD techniques. A maize stalk ash-supported Ni catalyst was developed for steam reforming of HOAc. The chemical composition and structural characteristics of CNC and Ni/MSA catalysts were compared. Evolution characteristics of H2 and CO during CSR of HOAc were explored. Between 600 and 900 °C, the yields of H2 and CO showed a similar trend over time, which first increased rapidly to the peak value, then began to decrease and finally tended to stabilize. The optimal reaction conditions were as follows: temperature = 800 °C, water to carbon molar ratio (WCMR) = 3, and weight hourly space velocity (WHSV) = 5 h–1. Elevating the reforming temperature up to 900 °C gave rise to the continuously increased H2 yield and enhanced catalyst ability for selective hydrogen production. The percentage of coke deposited on the catalyst decreased by 49.8% with the rise of temperature from 600 to 900 °C. The CO yield continued to decrease with increasing WCMR from 1 to 7. Ni/MSA gave similar CO yield to the CNC. The Ni/MSA exhibited better ability to selectively generate hydrogen than the CNC, resulting in significantly higher hydrogen yield.

Acceleration of acid red 1 dye decolorization efficiency by adding methanol with simultaneous hydrogen production

A promising and efficient pathway for simultaneous photocatalytic decolorization of acid red 1 (AR1) dye and hydrogen production was developed in this study. The results demonstrated that the AR1 decolorization efficiency was accelerated by adding only 15 v/v% methanol, which was attributable to the decreased charge recombination rate caused by methanol molecules. The decreased charge recombination rate led to increased ·OH and ·O2− group formation, resulting in better AR1 decolorization efficiency. The optimal AR1 decolorization efficiency and hydrogen production ability, respectively, reached 99.4% and 1127 μmol/h/g when the AR1 concentration and methanol concentration were, respectively, controlled to 6 mg/L and 15 v/v%. The enhanced AR1 decolorization efficiency was ascribed to the lower rate of electron–hole recombination. Due to the lower electron–hole recombination rate, more electron–hole pairs effectively produced superoxide radicals and hydroxyl radicals, which resulted in substantially enhanced AR1 decolorization efficiency.

Hydrogen promotion by Co/SiO2@HZSM-5 core-shell catalyst for syngas from plastic waste gasification: The combination of functional materials

In the present work, a core-shell structured Co/SiO2@HZSM-5 catalyst was prepared for hydrogen production from syngas of plastic waste gasification. The cobalt catalyst was coated with HZSM-5 shell through a hydrothermal process, and the Co/SiO2@HZSM-5, with different loadings of HZSM-5 (e.g., 10–30 wt %) exhibited excellent activity and durability for dehydrogenation reactions. The amount of HZSM-5 was found to be an important factor for hydrogen production. Temperature-programmed reduction with H2 and temperature-programmed desorption of ammonia was applied to determine the active site and the acidity of prepared catalyst, respectively. The prepared Co/SiO2@HZSM-5 was tested through reforming of plastic gasification syngas and shown superior hydrogen production ability (∼90%) and stability (over 15 h). The effects of reduction-oxidation behavior on the catalytic performance were also discussed.

Facile synthesis of thin black TiO2 − x nanosheets with enhanced lithium-storage capacity and visible light photocatalytic hydrogen production

In combination of a facile and scalable solvothermal method and solid-phase reduction reactions, a novel two-dimensional black TiO2 − x nanosheet (TiO2 − x NS) with high specific surface area of 108 m2 g−1 and nearly total solar spectral absorption capability have been successfully prepared. With careful characterizations, the novel TiO2 − x NS showed enhanced electrochemical performance and visible-light photocatalytic activity than those of their white TiO2 nanosheet (TiO2 NS) precursors. The black TiO2 − x NS electrode delivered a reversible specific capacity of 160 mA h g−1 even after cycling at 0.5 C (1 C = 190 mA h g−1) for 300 times, which was significantly higher than the corresponding white TiO2 NS electrode (104 mA h g−1). Meanwhile, the TiO2 − x NS also exhibited enhanced ability of visible-light photocatalytic hydrogen production than that of the white TiO2 NS. It is expected that making white TiO2 NS into black ones is an effective way to design the photocatalysts with visible light response and the anodes with long lifetime and high rate performance in lithium ion batteries. The novel black TiO2 − x NS could find potential applications in the field of environmental management and energy storage and conversion.

MoS2 nanosheet incorporated α-Fe2O3/ZnO nanocomposite with enhanced photocatalytic dye degradation and hydrogen production ability.

We have synthesized MoS2 incorporated α-Fe2O3/ZnO nanocomposites by adapting a facile hydrothermal synthesis process. The effect of incorporating ultrasonically exfoliated few-layer MoS2 nanosheets on the solar-light driven photocatalytic performance of α-Fe2O3/ZnO photocatalyst nanocomposites has been demonstrated. Structural, morphological and optical characteristics of the as-synthesized nanomaterials are comprehensively investigated and analyzed by performing Rietveld refinement of powder X-ray diffraction patterns, field emission scanning electron microscopy and UV-visible spectroscopy, respectively. The photoluminescence spectra of the as-prepared nanocomposites elucidate that the recombination of photogenerated electron–hole pairs is highly suppressed due to incorporation of MoS2 nanosheets. Notably, the ultrasonicated MoS2 incorporated α-Fe2O3/ZnO nanocomposite manifests 91% and 83% efficiency in degradation of rhodamine B dye and antibiotic ciprofloxacin respectively under solar illumination. Active species trapping experiments reveal that the hydroxyl (˙OH) radicals play a significant role in RhB degradation. Likewise the dye degradation efficiency, the amount of hydrogen produced by this nanocomposite via photocatalytic water splitting is also considerably higher as compared to both non-ultrasonicated MoS2 incorporated α-Fe2O3/ZnO and α-Fe2O3/ZnO nanocomposites as well as Degussa P25 titania nanoparticles. This indicates the promising potential of the incorporation of ultrasonicated MoS2 with α-Fe2O3/ZnO nanocomposites for the generation of carbon-free hydrogen by water splitting. The substantial increase in the photocatalytic efficiency of α-Fe2O3/ZnO after incorporation of ultrasonicated MoS2 can be attributed to its favorable band structure, large surface to volume ratio, effective segregation and migration of photogenerated electron–hole pairs at the interface of heterojunctions and the plethora of exposed active edge sites provided by the few-layer MoS2 nanosheets.

Study on the hydrogen production ability of high-efficiency bacteria and synergistic fermentation of maize straw by a combination of strains.

Based on the principle of reciprocal symbiosis and co-metabolism of mixed culture microorganisms, a group of high-efficiency maize straw-degrading hydrogen-producing complex bacteria X9 + B2 was developed by a strain matching optimization experiment. Systematic research and optimization experiments were carried out on the mechanism of the main controlling factors affecting the hydrogen production of the complex bacteria. The results showed that the optimum conditions for the acid blasting pre-treatment of maize straw as a substrate were as follows: when the inoculation amount was 6% and the inoculum ratio was 1 : 1, at which point, we needed to simultaneously inoculate, the initial pH was 6, the substrate concentration was 12 g L−1, and the culture time was 40 h. The complex bacteria adopted the variable temperature and speed regulation hydrogen production operational mode; after the initial temperature of 37 °C for 8 hours, the temperature was gradually increased to 40 °C for 3 hours. The initial shaker speed was 90 rpm for 20 hours, and the speed was gradually increased to 130 rpm. The maximum hydrogen production rate obtained by the complex bacteria under these conditions was 12.6 mmol g−1, which was 1.6 times that of the single strain X9 with a maximum hydrogen production rate of 5.7 mmol g−1. Through continuous subculturing and the 10th, 20th, 40th, 60th, 80th, 100th and 120th generation fermentation hydrogen production stability test analysis, no significant difference was observed between generations; the maximum difference was not more than 5%, indicating better functional properties and stability.

Photocatalytic performance of Ag2S/ZnO/ZnS nanocomposites with high visible light response prepared via microwave-assisted hydrothermal two-step method.

A series of different ratios of Ag2S/ZnO/ZnS nanocomposites with visible light response were prepared by a microwave-assisted hydrothermal two-step method, whose composition, crystalline structure, morphology and surface physicochemical properties were well-characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis/DRS), photoluminescence spectrum (PL), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N2 adsorption-desorption measurements. Results showed that as-composites mainly consisted of ZnS crystal phase, whose grain size increased obviously compared with non Ag2S samples. At the same time, due to the introduction of narrow band gap Ag2S, the synthesized composite can effectively increase the visible optical absorption of ZnO/ZnS composites. Among them, 1% Ag2S/ZnO/ZnS showed a mixed structure of nano-line and nano-particle, of which BET value increased significantly, and the morphology was more excellent. Photocatalytic activities of a series of Ag2S/ZnO/ZnS composites under different light sources were studied using methyl orange as a model molecule, and 1% Ag2S/ZnO/ZnS was taken as the best one. Meanwhile, 1% Ag2S/ZnO/ZnS also showed a good degradation effect on other dyes with different structures, and its degradation efficiency did not change significantly after three cycles, showing certain stability. In addition, composites with Ag2S loading of 1% possessed the highest hydrogen production ability of photolysis water, indicating that the introduction of Ag2S had significantly enhanced the catalytic performance.

Effects of supercritical fluids in catalytic upgrading of biomass pyrolysis oil

The catalytic upgrading of biomass pyrolysis oil (bio-oil) was performed under supercritical conditions. The behaviors of solvents with MgNiMo/AC were investigated for use of methanol, ethanol, butanol, hexanol, and formic acid as supercritical fluids. The production of gases including hydrogen, carbon monoxide, carbon dioxide, and methane was analyzed, and changes in the compositions of esters, alcohols, and phenols were examined. When the catalyst dosage and temperature were increased, the production of hydrogen increased. Among the alcohols, methanol produced the highest amount of hydrogen, and butanol produced the lowest amount of hydrogen. Formic acid showed good hydrogen-production ability. After catalytic upgrading of bio-oil, there was a decrease in oxygen and moisture content and an increase in the higher heating value (HHV). With an extended reaction time, the oxygen content was lowered further. During the supercritical ethanol reaction at 340 °C under an initial 30 bar of N2 gas for 2 h the oxygen content decreased from 33.9 to 14.6 wt% and the HHV increased from 25.2 to 35.3 MJ/kg.

High carriers transmission efficiency ZnS/SnS2 heterojunction channel toward excellent photoelectrochemical activity

AbstractZnS has been found superiority in photoelectrochemistry for the fast response of photo‐inducing and its high conductor band position (~0.8 eV) results in strong reduction ability for hydrogen production. However, the solar absorbance of ZnS is much low for the wide band gap (~3.2 eV) and the carriers’ migration efficiency also need to be improved. Here, nano‐ZnS were coupled with ultrathin SnS2 nanosheets as heterojunction composites. This heterojunction composite demonstrated largely increase in specific surface area (from 4 to 12‐25 m2/g), obvious improvement of UV‐vis absorbance and narrower band gap. Furthermore, the carriers’ migration efficiency of ZnS/SnS2 heterojunction has been confirmed to be much higher by photocurrent response and electrochemical impedance spectroscopy. Due to the improvement in structure, compared with pristine ZnS, this ZnS/SnS2 heterojunction exhibited vast enhancement in photoelectrochemical performance. The composite with best activity exhibited 12.8 times enhancement in photocurrent density. The conduction band and valence band of ZnS are both more negative than those of SnS2, the photo‐induced electrons at the conduction band of ZnS will transfer into the conduction band of SnS2 while the photo‐induced holes at the valence band of SnS2 will transfer into the valence band of ZnS. In this way, the photo‐produced carriers will flow into different semiconductors and the carriers’ migration efficiency is enhanced. The work improves a new structure to develop the heterojunction property for photoelectrochemical application.

Titanium Oxiynitride Catalyzed Activated Carbons As the Hydrogen Production in Sulfuric Acid Solution

Hydrogen production by water electrolysis is one of the techniques for establishment of the economy using hydrogen as an energy source. At the present, platinum group elements are used as the electrode catalyst for both anode and cathode in the acid medium, leading to be high initial cost of the water electrolysis system. We recently found that titanium oxiynitride catalyzed activated carbon (TiON/AC) has a low overpotential for hydrogen production in the acidic electrolyte. The overpotential is around 40 mV, which is very low among the catalyst based on the non-noble metals. In this presentation, we report the preparation of TiON/AC and its hydrogen production ability. TiON/AC is successfully obtained through two-steps as loading of titanium dioxide (TiO2) on activated carbon powder and then the nitridation. At first, deposition of TiO2 on the activated carbon was carried out by a modified liquid-phase deposition (LPD) method, in where H3BO3 and (NH4)2TiF6 aqueous solutions were used. A desired amount of activated carbon powder [specific surface area is 2343 m2/g purchased from Kuraray. Co., Ltd.] was added into H3BO3 aqueous solution. Then, (NH4)2TiF6 aqueous solution was added under stirring. The product was mounted in an alumina boat. Subsequent NH3 nitridation was carried out at 700, 750, 800 and 900°C. The characterization was performed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and X-ray photoelectron spectroscopy (XPS). To evaluate hydrogen production ability of TiON/AC, the water electrolysis experiment was demonstrated by using 0.5 mol dm-3 of sulfuric acid solution as the electrolyte. The working electrode (cathode) was prepared by TiON/AC carbon paper. A carbon paper and Ag|AgCl were used as the counter and the reference electrode, respectively. Hydrogen was quantified by a gas chromatography during chronoamperometry. Figure 1 shows the XRD patterns before and after NH3 nitridation at 700, 750, 800 and 900oC. Before the nitridation, the diffraction peaks assigned to both the anatase phase of TiO2 and carbon were recognized. After the nitridation at 700oC, the peaks assigned to TiO2, TiN and TiO were appeared. Furthermore, the peaks assigned to TiN and TiO was obvious and the broad peak of carbon was also recognized when the nitridation temperature was over 750oC. In addition, from the XPS results, the formation of Ti-O-N and O-Ti-N bonding were confirmed. Therefore, we considered that the nitridation of TiO2 to TiON was surely happened over 750oC. Figure 2 shows FE-SEM images of the product after the nitridation of 800oC. The tiny particles as 30 nm were found on AC substrate. These particles were considered the products composed of titanium, nitrogen and oxygen. The hydrogen production rate was estimated from the results of gas chromatography. And, its dependency on the overpotential was shown in Figure 3. Hydrogen production was confirmed at overpotential = 0.1 V for the products after the nitridation of 800 and 900oC. The products obtained at 900oC of the nitridation shows the highest hydrogen production rate. This work was partially supported by the Matching Planner Program from Japan Science and Technology Agency , JST and JSPS KAKENHI Grant Number 16K05940. Figure 1

Enhanced photocatalytic dye degradation and hydrogen production ability of Bi25FeO40-rGO nanocomposite and mechanism insight

A comprehensive comparison between BiFeO3-reduced graphene oxide (rGO) nanocomposite and Bi25FeO40-rGO nanocomposite has been performed to investigate their photocatalytic abilities in degradation of Rhodamine B dye and generation of hydrogen by water-splitting. The hydrothermal technique adapted for synthesis of the nanocomposites provides a versatile temperature-controlled phase selection between perovskite BiFeO3 and sillenite Bi25FeO40. Both perovskite and sillenite structured nanocomposites are stable and exhibit considerably higher photocatalytic ability over pure BiFeO3 nanoparticles and commercially available Degussa P25 titania. Notably, Bi25FeO40-rGO nanocomposite has demonstrated superior photocatalytic ability and stability under visible light irradiation than that of BiFeO3-rGO nanocomposite. The possible mechanism behind the superior photocatalytic performance of Bi25FeO40-rGO nanocomposite has been critically discussed.

Sol-gel synthesis of DyCrO3 and 10% Fe-doped DyCrO3 nanoparticles with enhanced photocatalytic hydrogen production abilities.

DyCrO3 and 10% Fe-doped DyCrO3 nanoparticles have been synthesized using a sol–gel method to investigate their performance in photocatalytic hydrogen production from water. The synthesized nanoparticles have been characterized by performing X-ray diffraction, energy dispersive X-ray spectroscopy and UV-visible spectrophotometric measurements. In addition, field emission scanning electron microscopy has been performed to observe their size and shape. The Fe-doped DyCrO3 nanoparticles show a significantly smaller band gap of 2.45 eV compared to the band gap of 2.82 eV shown by the DyCrO3 nanoparticles. The Fe-doped DyCrO3 nanoparticles show better photocatalytic activity in the degradation of rhodamine B (RhB) compared to the photocatalytic activity shown by both the DyCrO3 and Degussa P25 titania nanoparticles. The recycling and reuse of Fe-doped DyCrO3 four times for the photo-degradation of RhB shows that Fe-doped DyCrO3 is a stable and reusable photocatalyst. To evaluate the extent of the photocatalytic hydrogen production ability of the synthesized nanoparticles, a theoretical model has been developed to determine their “absorptance”, a measure of the ability to absorb photons. Finally, 10% Fe-doped DyCrO3 proves itself to be an efficient photocatalyst as it demonstrated three times greater hydrogen production than Degussa P25.

Feasibility of a Wind-Hydrogen Energy System Based on Wind Characteristics for Chabahar, Iran

Abstract The knowledge of wind speed characteristics of a region is among the most important aspect of wind turbines utilization for electricity production and assessing the cost of power generation. The wind spectrum and the wind power density for the city of Chabahar located in the southeastern part of Iran were modeled using Weibull distribution and power law estimation. An empirical approach was used to determine the shape parameter, k, and the scale parameter, c, of Weibull distribution function at different heights from 2014 to 2016 during two years period. Wind characteristics in Chabahar were extensively analyzed along with assessing the effects of parameters such as air humidity and temperature, surface roughness, turbulence, and wind velocity durations. The amount of wind power that can be produced by installation of eight wind turbines with different powers ranging from 2.5 kW to 8 MW at Chabahar were investigated. Additionally, the annual capacity factor for each turbine was determined. A wind-hydrogen system was considered in the analysis for evaluating the hydrogen production ability from wind energy in the station at Chabahar. The highest amount of hydrogen production was related to Vestas V164 with the yearly value of 194.36 ton-H2.

R&D status in thermochemical water-splitting hydrogen production iodine-sulfur process at JAEA

The IS process is the most deeply investigated thermochemical water-splitting hydrogen production cycle. It is in a process engineering stage in JAEA to use industrial materials for components. Important engineering tasks are verification of integrity of the total process and stability of hydrogen production in harsh environment. A test facility using corrosion-resistant materials was constructed. The hydrogen production ability was 100 L/h. Operation tests of each section were conducted to confirm basic functions of reactors and separators, etc. Then, a trial operation for integration of the sections was successfully conducted to produce hydrogen of about 10 L/h for 8 hours.

The effect of methanogenesis inhibition, inoculum and substrate concentration on hydrogen and carboxylic acids production from cassava wastewater.

Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2.3-L flasks during two operational phases. In the first phase (P1), inhibition of methanogens in the sludge was evaluated using acetylene (1% v/v of headspace) and heat treatment (120°C, 1atm for 30min). In the second phase (P2), three inoculum types obtained from common anaerobic sludges (bovine rumen and sludges from municipal and textile industrial wastewater treatment plants) were individually assayed. P2 aimed to identify the best inoculum, based on hydrogen production ability, which was tested for three initial concentrations of manipueira in terms of chemical oxygen demand (COD) (10, 20 and 40g O2/L). Results of P1 indicated that either acetylene or heat treatment efficiently inhibited methanogenesis, with no methane production. However, the maximum H2 production potential by applying heat treatment (~563mL) was more than twice compared with that by acetylene treatment (~257mL); and butyrate was the main carboxylic acid by-product (~3g/L). In P2 experiments after sludge heat treatment, the highest hydrogen yield (1.66±0.07mol H2/mol glucose) and caproic acid production (~2g/L) were observed at 20g O2/L of manipueira COD, when bovine rumen was the inoculum. The primary metabolic degradation products in all P2 experiments were ethanol, acetic, butyric, propionic and caproic acids. The finding of caproic acid detection indicated that the applied conditions in manipueira anaerobic degradation favored carbon chain elongation over methanogenesis.

A new natural layered clay mineral applicable to photocatalytic hydrogen production and/or degradation of dye pollutant

In this work, preparation and characterization of Hangjin2# clay (HC) photocatalyst, a new type of low cost natural metal‐oxide based on clay mineral from Inner Mongolia of China, was presented. The photocatalytic activity of HC was evaluated through the photocatalytic water splitting and the photodegradation of wastewater pollutants in aqueous suspension. The effects of CH3OH, Na2S–Na2SO3, and triethanolamine (TEOA) on the effectiveness of photocatalytic water splitting were investigated, respectively, which indicated that HC in all sacrificial reagents system had better hydrogen production ability than P25‐TiO2. An enhanced photocatalytic degradation of methyl orange (MO) in the presence of HC was detected. Moreover, photocatalytic activity and catalyst stability were maintained after consecutive recycling cycles in water splitting and degradation of wastewater, respectively. The relationship between the photocatalytic properties, the structure, and the morphology of the HC was discussed. Results indicated that the light‐induced photocatalytic activity of HC was mainly attributed to the synergies between hierarchical structure and the distribution of foreign metal atoms in its crystal lattice. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1003–1010, 2018

Fermentative hydrogen production from indigenous mesophilic strain Bacillus anthracis PUNAJAN 1 newly isolated from palm oil mill effluent

In the present study, a new mesophilic bacterial strain, identified as Bacillus anthracis strain PUNAJAN 1 was isolated from palm oil mill effluent (POME) sludge, and tested for its hydrogen production ability. Effect of physico-chemical factors such as temperature, initial pH, nitrogen source and carbon sources were investigated in order to determine the optimal conditions for hydrogen production. The maximum hydrogen yield of 2.42 mol H2/mol mannose was obtained at 35 °C and initial pH of 6.5. Yeast and mannose were used as the main carbon and nitrogen sources respectively in the course of the hydrogen production. Apart from synthetic substrate, specific hydrogen production potentials of the strain using POME was calculated and found to be 236 ml H2/g chemical oxygen demand (COD). The findings of this study demonstrate that the indigenous strain PUNAJAN 1 could be a potential candidate for hydrogen using POME as substrate.