HU-ACE News Letter Vol.42was published.  (Click)

The 87th Hiroshima University Biomass Evening Seminar was held

(The 71th Hiroshima University ACE Seminar)

Date & Time: Mon.28 Sep.,2020   16:20-17:50

Place: Engineering Medium conference room(A1-141), Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

Lecture: Yutaka NAKASHIMADA

Professor, Graduate School of Integrated Sciences for Life, Hiroshima University

“Carbon recycled chemical production by syngas fermentation “

Most of the chemicals in Japan are manufactured from petroleum-derived raw materials. As chemical raw materials use about 23% of petroleum consumption, they are in the situation of emitting a large amount of CO₂. For this reason, the Ministry of Economy, Trade and Industry presented a carbon recycling technology roadmap in June 2019 with the aim of reducing CO₂ emissions. Among these, the development of new chemical manufacturing technology that contributes to CO₂ emission reduction is required. In particular, the development of new manufacturing methods for C3 and C4 chemicals, which are the core of plastic raw materials, is required. As a method of using biomass and waste plastics as raw materials for polymers, the manufacturing technology using synthetic gas as an intermediate is called the synthetic gas platform. So far, we have been conducting research and development focusing on syngas fermentation. Syngas fermentation is a bulk chemical production technology that uses microorganisms that can produce C2-C4 compounds from synthetic gas without using expensive catalysts or toxic catalysts. In this talk, I would like to introduce some of the syngas fermentation technology we have developed and the possibility of carbon recycling by this technology.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

HU-ACE News Letter Vol.41was published.  (Click)

HU-ACE News Letter Vol.40was published.  (Click)

HU-ACE News Letter Vol.39was published.  (Click)

The 86th Hiroshima University Biomass Evening Seminar

(The70th Hiroshima University ACE Seminar)was held

Date & Time: Mon.13 Jul., 2020   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

Lecture: Shinnosuke MIYASAKO

M1 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“Behavior of organic phosphorus in hydrothermal treatment”

This experiment was conducted to confirm the mineralization characteristics of phosphatidylcholine under hydrothermal treatment condition. In this study, I conducted the experiment using phosphatidylcholine dissolved in water (concentration is 1.0 wt%). It is organic phosphorus mainly contained in sewage sludge belonging to waste biomass. The experimental equipment was continuous reactor consisting of SUS316 1/8 inch tube and 1/16 inch tube. In addition, the experiment was conducted by changing the conditions of residence time and reaction time.

Lecture: Hajime TAGAMI

M1 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“The reaction behavior of glyceraldehyde under hydrothermal conditions”

Hydrothermal treatment is drawing attention because it has various uses such as pretreatment of biomass and acquisition of useful substances, and it is an environmentally friendly method that uses only water. However, if the temperature or pressure changes, the reaction that occurs in the hydrothermal reaction field and the reaction that is accelerated also differ, so it is important to know how the temperature and pressure affect the reaction. In this study, the gas and liquid products obtained by reacting glyceraldehyde at a temperature of 300 ℃ and pressures of 15, 20 and 25 MPa for 1 to 40 s were analyzed to determine the reaction rate constant.

Lecture: Kanta OGAWA

M2 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“Detection of Formic Acid Using In-Situ Mass Spectrometry in Hydrothermal Reaction Field”

Hydrothermal reaction field is often employed for biomass conversion, but due to its high temperature and pressure, it is not easy to detect the chemical species in the reactor. Products are often analyzed after cooling down and depressurization, but the possibility of reaction during these steps cannot be denied. Thus, in-situ mass spectrometry has been proposed to directly analyze the chemical species in the reactor. However, so far this technology can be applied only to temperature lower than 250 . In this study, we improved the operation so that analysis from the reactor temperature or 400 is successfully conducted. Decomposition of formic acid was observed.

Lecture: Akira WAKI

M1 student, Graduate School of Integrated Sciences for Life, Hiroshima University

“Exploration of marine chitin-degrading flora from estuarine sediments and production of VFAs“

Chitin is a polysaccharide composed of n-acetylglucosamine. Since it is the second most abundant biomass in the natural after cellulose, it is a promising renewable resource with industrial potential. However, since it is an insoluble and hard-to-decompose polymer having a very hard structure, it cannot be decomposed by generally industrially used microorganisms such as Escherichia coli and yeast. Therefore, in this study, we exploration the marine chitin-degrading flora that efficiently decomposes chitin and produces volatile fatty acids (VFAs) and examined the properties of the flora.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

HU-ACE News Letter Vol.38was published.  (Click)

HU-ACE News Letter Vol.37was published.  (Click)

The 85th Hiroshima University Biomass Evening Seminar

(The 69th Hiroshima University ACE Seminar)was held

Date & Time: Mon.15 Jun., 2020   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

Lecture: Satoshi KATAYAMA

M1 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“Carboxylic Acid Production by Hydrothermal Treatment of Glucose”

It is essential to obtain oil alternative fuels from biomass for the realization of a sustainable society. It is expected that high quality oil can be obtained by using microorganisms. It is possible that carboxylic acid can be produced relatively easily by using biomass technology as one of the substrates that microorganisms are able to utilize. In this study, we conducted a hydrothermal treatment using glucose as a model compound of biomass and confirmed the production characteristics of carboxylic acid.

Lecture: Yoshiyasu ITO

M1 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“Trial on suppression of char generation in supercritical water gasification using high concentration biomass model compounds”

In the supercritical water gasification, there is a problem that substances such as char and tar are generated with gasification and block the reactor, and it is required to study the suppression of these generations. In this study, we conducted supercritical water gasification of model compounds of lignocellulosic biomass. A mixture of glucose, xylose and guaiacol having a concentration of 2.5 wt% to 7.5 wt% was used as a raw material, and each of solid, liquid and gas products obtained by gasification was analyzed.

Lecture: Hiroshi YOSHIOKA

M2 student, Graduate School of Advanced Science and Engineering, Hiroshima University

「Research on pretreatment of bamboo」

Today, global warming caused by fossil fuel is a problem all over the world. Therefore, biomass is attracting attention. Bamboo is attracting even in its biomass. Bamboo is abundant in Japan. And bamboo’s growth is so fast. So if it can be used as biomass, it has the potential to be a great energy source. However, there is a problem when bamboo is burned as biomass. That is generating clinker. Clinker is generated when potassium of bamboo is burned. This clinker stick boiler’s wall, and cause corrosion of boiler. So, we need to remove potassium of bamboo for using as biomass resources. I thought supercritical methanol is effectiveness for pretreatment of bamboo. Because, I thought bamboo’s potassium is eluted by supercritical methanol. The experiments are carried out using supercritical methanol in this pretreatment for the first time. For that reason, I investigated the behavior of bamboo’s potassium by using supercritical methanol. I treated bamboo with methanol and then studied the proportions of inorganic and organic material. Finally, I understood effect of methanol treatment.

Lecture: Yuta HIROSE

M2 student, Graduate School of Advanced Science and Engineering, Hiroshima University

“Cleaning of exhaust gas from pellet stove“

Pellet stove have some problems to use instead of them. For example, the exhaust gas from pellet stove contains much soot, CO2, CO and some gas which harmful for human health. So it is difficult to use in residential area. Therefore, it is important to remove these things from exhaust gas from pellet stove. In this research, we spray the water to the exhaust gas from pellet stove which contain soot to remove the soot. Heating power of pellet stove which is used in this research can be changed in 5 levels. This experiment was conducted in heating power 1, 3, 5 with spray or no spray. The results of this study, the soot from pellet stove was reduced 70 ％ in heating power 3. Furthermore, the soot from pellet stove was reduced 91 ％ in heating power 5.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Advanced Science and Engineering, Hiroshima University

HU-ACE News Letter Vol.36was published.  (Click)

HU-ACE News Letter Vol.35was published.  (Click)

The 84th Hiroshima University Biomass Evening Seminar (Tte 68st HU-ACE seminar), which was scheduled for April 20 (Mon), has been canceled due to the difficulty of securing the room.

Next seminar will be held on Monday, May 18, 2020. Please join.

Director Biomass Project Research Center, Hiroshima University

Yukihiko Matsumura

The 82th Hiroshima University Biomass Evening Seminar

(The 65th Hiroshima University ACE Seminar)was held.

Date & Time: Mon .10 Feb., 2020   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary : Yukihiko MATSUMURA

Professor, Graduate School of Engineering ,HiroshimaUniversity

Lecture: Ran HIROTANI

M2 student, Graduate School of Advanced Sciences of Matter, Hiroshima University

“Development of new Gas-tO-1ipids bioprocess with acetogen and Oleaginous　microorganism”

Fossil resources currently play dominant roles in energy production, but there are concerns　about depletion of fossil resources and negative impacts on the global environment of CO2　discharged by fossil fuel consumption. To solve these problems, we aim to establish　biorefinery technology using Labyrinthulean protist, genus Aurantiochytrium producing lipids which are usable in various industrial fields. I will introduce the construction of two-stage fermentation system comblning acetogenic bacteria and Aurantiochytrium sp. To　produce useful lipids from CO2 gas.

Lecture: Kyohei HORIO

M2 student, Graduate School of Advanced Sciences of Matter, Hiroshima University

“In Situ RNA Detection Tbward Elucidation of Functiona.1 Consortium”

RNase H-aSSisted RCA (RHa-RCA) has been developed to detect mRNA directly and to　recognize functional genes. mRNA is an important molecule to recognize functional genes,　therefore, this method will be applicable to elucidate the localization of functional genes in　microbial community without detecting signal derived from genomic DNA. In order to　visualize the ce11 itself, in this study, We developed RHa-RCA combined with fluorescence in situ hybridization. As a result, specific fluorescence to pyruvate-formate lyase activase gene in Streptococcus thermophilus was detected within harvested microbiome from yogurt. The results suggest that this method wi11 be useful tool to clarify microbiome by identifying the “owner” of functional gene.

Lecture : Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

“Biomass Utilization as Carbon Source for 2050”

Considering the whole renewable energy trend, cost reduction of photovoltaic is prominent and its introduction is expected only if battery system is available. Meanwhile, countries like China is introducing electric vehicles, which will accelerate the utilization and cost reduction of batteries. The role of biomass in this situation should be considered not in terms of power generation but in terms of carbon source. Possibility of biomass as carbon source in our country is discussed based on the energy statistics along with the scenario of zero emission of carbon dioxide in 2050.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

The 81th Hiroshima University Biomass Evening Seminar

(The 64th Hiroshima University ACE Seminar)was held.

Date & Time: Mon .20 Jan., 2020   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

Lecture: Ali MOHAMMED

MI Student, Graduate School of Engineering, Hiroshima University

“Behavior of Multiwalled Carbon Nanotube Catalyst Under Supercritical Water Condition in a Continuous Flow Reactor”

Carbon catalysts have been attracting attention from many researchers for different approaches due to its an important role in biomass. Multiwa11ed carbon nanotube (MWCNT) is a possible biomass catalyst. In this study MWCNT was used as a feedstock and gasified under supercritical water using a laboratory scale continuous flow reactor. The behavior of MWCNT including carbon gasification efficiency, gas composition, total organic carbon in the liquid product and solids products are discussed.

しecture: Hiroki YOKOYAMA

M2 Student, Graduate SchooI of Engineering, Hiroshima University

“Behavior of Glycine in Supercritical Water Gasification in Less than 5 s”

Supercritical water gasification (SCWG) is attracting attention because it can convert biomass quickly and almost completely. When nitrogen containing feedstock is to be gasified, behavior of nitrogen under hydrothermal conditions is important. There are some studies about amino acid decomposition in subcritical condition. It is also known that ionic reactions mainly take Place under subcritical condition. As for supercritical conditions, amino acid is known to decompose rapidly, and its decomposition rate has not been determined due to its short reaction time. In this study, We conducted SCWG of glycine in less than 5 s. The experiment was conducted using a tubular flow reactor at 25 MPa and glycine was empIoyed as feedstock. Order of the decomposition rate was determined.

Lecture: Makoto HIRAYAMA

Lecturer, Program of Food and AgriLife Science, Graduate SchooI of Integrated Sciences for Life, Hiroshima University

“Precipitate Recovery of Calcium Phosphate from Hydrothermally Treated Adenosine Triphosphate’’

Our group has isolated more than 70 1ectins, Sugar-binding proteins, from algae and elucidated that algal lectins show novelties of molecular structures and carbohydrate recognition mode. The unique binding properties of alga lectins are applicable as diagnostic tooIs and phamaceuticals: Several algal lectins specifically recognize glycan markers of cancers and show strong anti-viral activities against HⅣ and influenza viruses, Which possess the characteristic glycans on their envelope. In this talk, structural and functional features of

algal lectins are summarized and highlighted towards more advanced usage of them.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

The 80th Hiroshima University Biomass Evening Seminar

(The 60th Hiroshima University ACE Seminar)was held.

Date & Time: Mon .16 Dec., 2019   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

Lecture: Kanta OGAWA

M1 Student, Graduate School of Engineering, Hiroshima University

“5-Hydroxymethylfulfural Production in Hot Compressed Water Using Magnetic Catalyst”

Material production from biomass is important, and 5-hydroxymethylfulfural (5-HMF) is one of the important platform chemicals. It is easily produced from sugars in hot compressed water, but recovery of catalyst has been a challenge. To improve the catalyst collection, magnetic catalyst is attractive, but no one has studied its effect. In this study, we employed magnetic carbon nanocatalyst, and succeeded to produce 5-HMF in hot compressed water.

Lecture: Hiroshi YOSHIOKA

M1 Student, Graduate School of Engineering, Hiroshima University

“Life cycle energy and CO2 of microalgae biodiesel production”

Microalgae is expected to be a promising oil producing biomass that can be used for biodiesel production. However, there is discussion on whether it is actually feasible. This study aims to compare three different biodiesel production methods, catalytic, in-situ, and supercritical, on the net energy ratio and CO2 emission.

Lecture: Yoshiki FUJIWARA

M2 Student, Graduate School of Engineering, Hiroshima University

“Precipitate Recovery of Calcium Phosphate from Hydrothermally Treated Adenosine Triphosphate”

Adenosine triphosphate (ATP) was treated at 350℃, 25 MPa for residence time of 20 s in the reactor made of SS316 steel tubing (i.d. 2.17 mm, o.d. 3.18 mm, and length 0.27 m). Calcium phosphate was recovered from ATP as precipitate by adding calcium nitrate. Trial to recover the precipitate at the exit of the reactor using sintered stainless filter was not successful. Therefore, in this study, the precipitate position of generated precipitate was investigated.

Lecture: Yuta HIROSE

M1 Student, Graduate School of Engineering, Hiroshima University

“Feasibility of conducting a 2-Stage Subcritical hydrothermal treatment of microalgae biomass”

Hydrothermal carbonization (HTC) allows carbonization of wet biomass to effectively utilize it. There is no need of drying process, so we can save energy to dry wet biomass. One of the promising feedstock is microalgae. In spite of large number of research about HTC of microalgae, they are all discussing energy of end products from 1-stage subcritical hydrothermal treatment. 2-stage subcritical hydrothermal treatment of microalgae should allow production of value added product in addition to energy. In this study, we investigated the effectiveness of 2-Stage treatment for hydrothermal carbonization.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

The 79th Hiroshima University Biomass Evening Seminar

(The 59th Hiroshima University ACE Seminar)was held.

Date & Time: Mon .18 Nov., 2019   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

<Program>

Commentary: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

Lecture: Noah Luciano TAUFER

Visiting Research Scholar, Graduate School of Engineering, Hiroshima University

“Experimental Investigation into the Hydrothermal Carbonization of digestate and the Supercritical Water Gasification of the liquid product”

In the modern world, there is an ever growing need to find and exploit renewable energy sources. Climate change is a world-wide problem that must be confronted and solved. For this reason, renewable energies like biomass, solar, wind and hydropower have taken a strong foothold in the energy market, thanks to large public consensus and government subsidies. Among these, biomass is the most widespread and it is already the fourth largest energy source after coal, oil and natural gas. However, it is not always efficiently exploited through classical thermo-chemical treatments. In fact, a lot of biomass features high moisture content and must be treated with appropriate methods. Hydrothermal treatments are the most effective solution to treat wet biomass. This study investigates the ability of HTC to treat the solid residue of anaerobic digestion of cattle manure, which features very high-water content. Hydrothermal carbonization is performed at 180, 220, 250 °C for residence times of 3 hours under autogenous pressure. The main products, hydrochar (solid) and process liquid, are extracted and analysed. The next step consists in performing Supercritical Water Gasification of the process liquid, minimizing the wastes and producing a valuable gaseous energy vector rich of hydrogen. For this, a continuous flow reactor is used, and the HTC liquid is gasified at 600, 550 and 500 °C and at varying residence times in order to identify the ideal operating parameters. Finally, the solid, liquid and gaseous products are collected and analysed.

Lecture: Hiroki YOKOYAMA

M2 Student, Graduate School of Engineering, Hiroshima University

“Nitrogen Behavior in Supercritical Water Gasification of Glycine at the Initial Stage”

Supercritical water gasification(SCWG) is attracting attention because SCWG can convert biomass quickly, and almost completely. There are some studies about amino acid decomposition under subcritical condition, and they reported that ionic reaction mainly occurred under subcritical condition. On the other hand, it is well known that ion product dramatically decreases under supercritical condition. Discussion about behavior of nitrogen in SCWG in less than 5 s is insufficient though almost all nitrogen reactions are completed in less than 5 s. Therefore, we conducted SCWG of glycine in less than 5 s. The experiment was conducted using a tubular flow reactor at 25 MPa and glycine was used as a model compound of protein of biomass.

Lecture: Rahmat Iman MAINIL

D3 Student, Graduate School of Engineering, Hiroshima University

“Effect of Heating Rate on Supercritical Water Gasification of Palm Oil Mill Effluent”

Palm oil mill effluent (POME) is a problematic waste from palm oil production. It could cause severe pollution if no appropriate management is carried out. Among several technologies employed to utilize biomass waste as a source of energy, supercritical water gasification (SCWG) is the most promising candidate. SCWG is a technology to gasify biomass in hot compress water. The gasification is quick, and high carbon gasification efficiency (CGE) can be achieved. The CGE is known to be affected by the feedstock heating rate. However, the effect of heating rate on the conversion of POME has not understood yet. To study this effect, we treated POME in a continuous flow reactor at a constant temperature of 600 °C and controlled pressure 25 MPa with various preheater length (1,2, and 4 m). By comparing the results, effect of heating rate on the CGE and the phosphorus conversion was made clear.

Lecture: Puji Rahmawati NURCAHYANI

D3 Student, Graduate School of Engineering, Hiroshima University

“Influence of nutrient concentration on the phosphorus consumption and biomass productivity of microalgae Chlorella vulgaris.”

Microalgae are a photosynthetic biomass which grow faster compared to the land plant. In the growing period, these green algae need some nutrient with main composition of nitrogen, phosphorus and potassium. However, the consumption behavior of those nutrient has not been reported well. Therefore, we set this experiment to investigate the green microalgae Chlorella vulgaris in uptake of phosphorus for growing their biomass. The cultivation was set in batch reactor with volume of 900 ml. Room temperature was controlled for 20 oC, aeration was fed into the reactor with flowrate of 3 ml/min and the light intensity was 3.42 µmoles/m2/s with 24 h photoperiod. The medium concentration used was 10, 50, 100, 200 and 500 ppm. During cultivation period, microalgae sample were taken once in every 3 days and stopped in day 40th. We analyzed the cell weight of per ml sample. Other than that, we analyzed the phosphorus content in the medium using molybdenum blue method. As a result, the maximum biomass productivity was obtained in nutrient concentration of 100 ppm, while the consumption of phosphorus rate on this concentration was faster than that of the others. Furthermore, the use of higher concentration of phosphorus might inhibits the growth of microalgae cells.

Chair: Yukihiko MATSUMURA

Professor, Graduate School of Engineering, Hiroshima University

HU-ACE News Letter Vol. 34was published.  (Click)

HU-ACE News Letter Vol. 33was published.  (Click)

The 78th Hiroshima University Biomass Evening Seminar
(The 58th Hiroshima University ACE Seminar) was held.

Date & Time: Mon.7 Oct., 2019   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University
https://www.hiroshima-u.ac.jp/eng/access/lectureroom
https://www.hiroshima-u.ac.jp/eng/access/building
https://www.hiroshima-u.ac.jp/access/higashihiroshima

 <Program>

Commentary: Yukihiko MATSUMURA
  Professor, Graduate School of Engineering, Hiroshima University

Lecture: Puji Rahmawati NURCAHYANI
　D3  Graduate School of Engineering, Hiroshima University

“Kinetic rate of microalgae decomposition in supercritical water gasification.” 

Biomass is a renewable source for gaining energy. Microalgae, a unicellular photosynthetic biomass, was introduced as biooil energy sources, but its potential to produce gaseous energy source under supercritical water gasification needs to be clarified. We examined the decomposition of microalgae in water at 600 oC, 25 MPa with continuous reactor system. Results showed that liquid product was the main product besides of gas. We found char and tar as well. We developed a model with assumption that reactions taking place are first order reactions except the tarry material production that was expressed as second order reaction. The reaction rate of each reaction in the model was determined.

Lecture: Yoshiyasu ITO
　B4  School of Engineering, Hiroshima University

“Supercritical water gasification on high concentration model compound of woody biomass” 

Consider the use of biomass, the influence of supercritical water gasification was investigated using a mixed aqueous solution of glucose, xylose and guaiacol as a model compound of woody biomass. In previous studies, concentrations of glucose, xylose and guaiacol were performed at 0.1 wt%. However, at 0.1 wt%, the concentration was low and the practicality was lacking. Therefore, in this study, the influence of supercritical water gasification is studied using mixed aqueous solution with a concentration of 5 wt%.

 Lecture: Hiroshi YOSHIOKA
M1  Graduate School of Engineering, Hiroshima University

“ Research on pretreatment of bamboo” 

Today, global warming caused by fossil fuel is a problem all over the world. Therefore, biomass is attracting attention. Bamboo is attracting even in its biomass. Bamboo is abundant in Japan. And bamboo’s growth is so fast. So if it can be used as biomass, it has the potential to be a great energy source. However, there is a problem when bamboo is burned as biomass. That is generating clinker. Clinker is generated when potassium of bamboo is burned. This clinker stick boiler’s wall, and cause corrosion of boiler. So, we need to remove potassium of bamboo for using as biomass resources. I thought supercritical methanol is effectiveness for pretreatment of bamboo. Because, I thought bamboo’s potassium is eluted by supercritical methanol. The experiments are carried out using supercritical methanol in this pretreatment for the first time. For that reason, I investigated the behavior of bamboo’s potassium by using supercritical methanol. I treated bamboo with methanol and then studied the proportions of inorganic and organic material. Finally, I understood effect of methanol treatment.

Lecture: Yuta HIROSE
M1  Graduate School of Engineering, Hiroshima University

“ The possibility of pellet stoave improvement. ” 

Pellet stove use wood pellet as fuel. The wood pellet is made from sawdust which occurs when making wooden products. So wood pellet is carbon neutral and important to solve the environmental problem such as depletion of fossil fuel and global warming. Therefore it is good idea to use pellet stove instead of devices which use fossil fuels as fuel. However, pellet stove have some problems to use instead of them. For example, the exhaust gas from pellet stove contains much heating value, soot, CO2, CO and some gas which harmful for human health. So it is important to improve these problems. In this research, we considered about mass balance and energy balance. In addition, we researched about soot which contained exhaust gas from pellet stove.

 Chair: Yukihiko MATSUMURA
  Professor, Graduate School of Engineering, Hiroshima University

We will hold the discussion meeting from 18:00 (800 JPY needed).  Join this meeting, too if you are available.

Mechanical Seminar (The 57th Hiroshima University ACE Seminar)

Lecture：  Velayutham MURUGESAN, Annamalai University (India) 
Title:     Nano semiconducting Materials for Wastewater Remediation
Date：  9/20, 11:00-12:00
Place： Engineering A3-131 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University

Abstract：

Contamination of water resources by man-made industrial chemicals and pesticides interfere with the normal functioning of human and wildlife endocrine systems. A wide range of substances including pesticides, surfactants, plasticizers and organohalogens are collectively referred to as endocrine disruptors. The removal of endocrine disrupting chemicals (EDCs) from wastewater is a complex problem, and this cannot be resolved by conventional treatment methods. Photocatalytic degradation is a promising technique for mineralisation of various organic pollutants in wastewater including EDCs. Among the semiconductors employed, bulk TiO₂ is a good photocatalyst because of its high photosensitivity, non-toxicity, easy availability, strong oxidising power and long-term stability. Several attempts have been made to improve the efficiency of bulk TiO₂. Nanocrystalline TiO₂ is expected to offer better solution as it exhibits unique properties such as quantum size effect, high surface area, tunable surface properties and short interface migration distances, all of which enhance photocatalytic performance.

This presentation highlights the preparation, characterisation and photocatalytic performance of nano TiO₂, La³⁺, Gd³⁺ and Zr⁴⁺ doped nano TiO₂. The materials were prepared by sol-gel process and characterised using XRD, BET, FT-IR, TGA, UV-Vis, SEM, XPS and TEM. The band gap values of doped nano TiO₂ were higher than the pure nano TiO₂. The entry of dopant ion into the lattice of nano TiO₂ created charge compensating anion vacancy in the lattice points of nano TiO₂ which enhanced adsorption of pollutants. Further, the dopant ion like Zr⁴⁺ with ionic radius (0.79 Å) larger than Ti⁴⁺(0.75 Å) but smaller than O^2-(1.31 Å) can either isomorphously substituted or interstitially introduced into the matrix of nano TiO₂, thus producing oxygen vacancies which accelerate the transition and nanocrystallite growth of anatase form of nano TiO₂. The photocatalytic activity in the degradation of selected EDCs like monocrotophos, bisphenol-A, carbofuran and 2,4,6-trichlorophenol were found to be higher for doped nano TiO₂ than  pure nano TiO₂ and commercial TiO₂  (Degussa P-25). The influence of various parameters such as initial concentration of pollutants, catalyst loading, pH and light intensity were optimised for maximum degradation efficiency. The detailed results will be discussed in this presentation.