Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).Khả năng hấp phụ dinh dưỡng và giảm phát thải khí nhà kính của than tre (Bambusa blumeana) và than tràm (Melaleuca cajuputi).
MINISTRY OF EDUCATION AND TRAINING CAN THO UNIVERSITY Ph.D THESIS SUMMARY Special Issue: Land and Water Environment Code: 62440303 PHAM NGOC THOA THE CAPACITY OF BAMBOO (Bambusa blumeana) AND MELALEUCA (Melaleuca cajuputi) BIOCHAR TO ABSORB NUTRIENTS AND REDUCE GREENHOUSE GAS EMISSIONS YEAR 2022 COMPLETE OF WORK AT CAN THO UNIVERSITY Advisor: Assoc Prof Dr Nguyen Huu Chiem The thesis is defended before the university-level doctoral thesis grading committee Meeting at: Doctoral Thesis Defense Room (Meeting Room 3, 2nd Floor, Executive Building), Can Tho University At hour day month year Reviewer 1: Reviewer 2: Confirmation of review by the Chairman of the Board Thesis can be found at the library: - Learning Resource Center, Can Tho University - Vietnam National Library LIST OF DISCLOSED SCIENTIFIC WORKS International Magazine [1] Nguyen Xuan Loc, Do Thi My Phuong, Nguyen Huu Chiem, Ryota Kose, Takayuki Okayama, Pham Ngoc Thoa, Nguyen Dat Phuong and Takayuki Miyanishi 2018 Properties of Biochars Prepared from Local Biomass in the Mekong Delta, Vietnam Bioresources 13 (4): 7325-7344 (Thesis content) Domestic Magazine [2] Pham Ngoc Thoa, Nguyen Xuan Loc, Do Thi My Phuong, Nguyen Huu Chiem 2019 Study on adsorption of ammonium from aqueous solution by bamboo biochar Journal of Vietnamese Environment J.Viet Env Spec.Iss.APE 2019 Pp.95-103 (Thesis content) [3] Pham Ngoc Thoa, Tang Le Hoai Ngan, Nguyen Huu Chiem 2021 Research on ammonium adsorption capacity in biogas wastewater of bamboo biochar Journal of Natural Resources and Environment Science No 37, pp.26-36 (Thesis content) [4] Pham Ngoc Thoa, Tang Le Hoai Ngan, Dang Thi Minh Thuy, Nguyen Dat Phuong, Do Thi My Phuong, Nguyen Xuan Loc, Nguyen Huu Chiem 2021 Research on ammonium adsorption capacity in water environment of Melaleuca biochar Journal of Agriculture and Rural Development Volume 17, No 01, pp.129-136 (Thesis content) [5] Pham Ngoc Thoa, Tang Le Hoai Ngan, Do Thi My Phuong, Nguyen Xuan Loc, Le Thi Thanh Truc, Huynh Thi Hong Xuyen, Nguyen Ngoc Han, Nguyen Huu Chiem 2021 Research on the ability of nitrate adsorption in aqueous of biochar from Melaleuca Scientific Journal of Vinh University Volume 50 No 1A, p 40-53 (Thesis content) [6] Pham Ngoc Thoa, Tang Le Hoai Ngan, Dang Thi Minh Thuy, Nguyen Dat Phuong, Do Thi My Phuong, Nguyen Xuan Loc, Nguyen Huu Chiem 2021 Effect of pH, volume, time and nitrate concentration on nitrate adsorption capacity of bamboo charcoal in biogas wastewater Science Journal of Can Tho University Volume 57 Thesis Issue on Environment and Climate Change (2021), pp.1-10 (Thesis content) [7] Pham Ngoc Thoa, Tang Le Hoai Ngan, Nguyen Huu Chiem 2021 Effect of biochar from Melaleuca on growth and development of water spinach (Ipomoea aquatica Forsk) Scientific Journal of Vinh University Volume 50 No 3A, p 55-65 (Thesis content) [8] Pham Ngoc Thoa, Tang Le Hoai Ngan, Nguyen Huu Chiem 2021 Effect of biogas wastewater and melaleuca biochar on CH4 and N2O emissions from rice cultivation Journal of Science of Natural Resources and Environment No 40 Page 28-40 (Thesis content) CHAPTER 1: INTRODUCTION 1.1 THE URGENCY OF THE SUBJECT Biochar is a carbon-rich solid material created after hightemperature carbonization of biomass under anoxic conditions, contains a high carbon content, and is stable for hundreds to thousands of years after being extracted applied to the soil (Lehmann and Joseph, 2015) Some types have been used in NH4+ treatment and give good results such as corn residue coal at 400ºC-500ºC, 500ºC straw biochar, 600ºC eucalyptus biochar which can adsorb NH4+ with an amount from 0.7-4.5 mg N/1g biochar (Fidel et al., 2018), (Khalil et al., 2018), (Yao et al., 2012) Recent studies have shown that biochar has the ability to adsorb NO3- from solutions such as 600ºC cornstarch that can adsorb NO3- with an amount of 1.4-1.5 mg N.g-1 (Fidel et al al., 2018), or biochar modified from 600ºC bagasse can adsorb NO3- up to 28.21 mg N/g (Hafshejania et al., 2016) Currently, there are more and more research works recognizing the nitrogen adsorption potential of biochar and the application of biochar in water pollution control Another potential benefit of biochar is that the addition of this to soil has the potential to reduce N2O and CH4 emissions through sequestering soil carbon, and provide other benefits, such as improved fertility, retain soil moisture and increase crop yields However, the exact impact of this use on soil GHG emissions has mixed results in many case studies (Cayuela et al., 2014; Lorenz and Lal, 2014) Soil CH4 and N2O content increased significantly in some studies (Yanai et al., 2007; Zwieten et al., 2010; Jones et al., 2011; Wang et al., 2012), but decreased or not changes in other studies (Rogovska et al., 2011; Feng et al., 2012; Zheng et al., 2012; Case et al., 2014; Quin et al., 2015) For example, an experiment on rice soils supplemented with biochar produced from wheat straw resulted in a 41.8% reduction in N2O emissions (Zhang et al., 2012b) The livestock industry is currently thriving in the Mekong Delta, so large amounts of waste from livestock activities are posing a threat to aquatic ecosystems (Cruse et al., 2014) Although livestock waste has been treated through the biogas system, the wastewater after biogas still has a high concentration of dissolved ions, especially NH4+ and NO3ions, so it is necessary to take measures to manage this waste output Besides livestock, the Mekong Delta also produces a large amount of rice and vegetables, so farming activities also become one of the main sources of greenhouse gases, mainly N2O and CH4 In which, CH4 has a thermal radiation adsorption 21 times higher than that of CO2, contributing 16% to the process of increasing ambient temperature, the lifetime of CH4 is about 100 years N2O gas contributes 6% to increase the ambient temperature, has a very long period of existence in the atmosphere from 130-150 years N2O gas is formed by the decomposition of nitrogenous compounds in the soil, mainly from nitrogen fertilizers (IPCC, 2014) Currently, many methods have been applied to remove NH4+ and NO3- ions from water, in which the adsorption method is increasingly being noticed because of its simplicity, high efficiency, low cost, and ease of application applied in practice The main materials used as adsorbents to remove NH4+ and NO3- ions are usually zeolite and biochar The source of raw materials for biochar production is very diverse such as manure, sludge, and plant biomass (Lehmann et al., 2016) Meanwhile, the Mekong Delta is home to an abundant amount of plant biomass that can be utilized for producing biochar namely bamboo and melaleuca Bamboo (Bambusa Blumeana) is a species that is easy to grow and develop, has the ability to regenerate itself (Mohamed et al., 2007), very popular in Vietnam However, the rapid growth of bamboo forests and then turning into monoculture forests is responsible for reducing biodiversity and soil nutrients and destroying the physical structure of the soil (Yiping and Henley, 2010; Song et al al., 2011; Buckingham et al., 2011) On the other hand, until 2015, about 11.1 million hectares of natural forest remained, of which Melaleuca (Melaleuca Cajuputi) accounted for 176 thousand hectares (Bazile et al., 2016) It is estimated that nearly million tons of wood by-products are produced annually from natural forests (Agency, 2012) Improper management of this abundant biomass resource in the Mekong Delta will cause waste and contribute to an increased risk of environmental pollution Therefore, biochar production from these biomasses can reduce negative environmental impacts Bamboo and melaleuca biochar can be applied in the treatment of water pollution, while contributing to limiting the release of greenhouse gases in the agricultural production process, stemming from food problems Research on the topic "The capacity of bamboo (Bambusa blumeana) and melaleuca (Melaleuca cajuputi) biochar to absorb nutrients and reduce greenhouse gas emissions" 1.2 OBJECTIVES OF THE STUDY 1.2.1 Overall objectives Using biochar made from two materials, bamboo and melaleuca, is used to adsorb nutrients from wastewater after biogas and reduce emissions of greenhouse gases CH4 and N2O in Can Tho city, Mekong delta 1.2.2 Detail goal - Determination of ammonium and nitrate adsorption capacities of bamboo and melaleuca biochars in wastewater solution after biogas - Determine the ability to reduce CH4 and N2O emissions of bamboo and melaleuca biochars on rice and crop land 1.3 SCIENTIFIC AND PRACTICAL MEANINGS 1.3.1 Scientific significance The adsorbent is bamboo and melaleuca biochars, which has been created by a standard process (pyrolyzed in an inert gas environment (N2), without O2 and with a controlled temperature) The ability to absorb nutrients and greenhouse gases from biochar is determined through a series of experiments All the parameters obtained from the experiments are statistical according to modern scientific methods widely used in the world From there, as a basis for explaining the adsorption mechanism of biochar scientifically and logically 1.3.2 Practical significance Helping to treat organic pollution of water sources in agricultural production models such as gardens, ponds, and biogas is very popular in Vietnam's Mekong Delta Using biochar of bamboo and melaleuca after adsorbing NH4+ and NO3- as organic fertilizer Adding bamboo and melaleuca biochar to rice and upland crops helps improve soil physicochemical properties, and at the same time reduces the release of greenhouse gases such as CH4, N2O in rice and crop production The results of the study are also used to supplement materials for teaching, learning, and research in universities and research institutes In addition, the topic is also a valuable source of information to help local authorities formulate sustainable agricultural production plans for the future of the Mekong Delta 1.4 RESEARCH SCOPE The materials used to create biochar in the laboratory, including bamboo (Bambusa blumeana) and melaleuca (Melaleuca cajuputi) were collected in the Mekong Delta The topic focuses on researching and evaluating the potential of ammonium and nitrate adsorption in standard solution and biogas wastewater (feeding material is pig manure) of bamboo and melaleuca biochars in the laboratory of the Faculty of Environment and Natural Resources, Can Tho University Evaluation of the ability to reduce CH4 and N2O emissions on the model of growing rice and crops, under net house conditions, of the Faculty of Environment and Natural Resources, Can Tho University 1.5 RESEARCH CONTENT - Create biochar at temperature levels, including 500ºC, 700ºC and 900ºC from bamboo and melaleuca materials, then determine the physical and chemical properties of biochar - Investigation of ammonium and nitrate adsorption capacity in standard solution and wastewater after biogas of bamboo biochar and melaleuca biochar - Using bamboo and melaleuca biochar in addition to the soil helps to limit CH4 emissions on continuously flooded rice fields and N2O on cropland 1.6 THE THESIS'S NEW FEATURES For the first time in the study area, there were successes in: (1) producing standard biochar under controlled temperature conditions in an inert gas (N2) environment free of O2 (2) determine the ability of bamboo and melaleuca biochar to adsorb ammonium and nitrate from wastewater after biogas in the study area (3) Determine the extent to which bamboo and melaleuca biochar reduce emissions of CH4 in wet rice fields and N2O on vegetable land in the study area Figure 3.9 The gas collection model on rice 3.3.2 Experiment Identify the effects of bamboo biochar/melaleuca biochar on CH4 and N2O emissions on upland crop The experiment was conducted in a completely randomized design, under net house conditions to ensure light for plant growth and development (38-40 kLux), including treatments and replicates The soil for growing green vegetables is mixed with bamboo biochar (or melaleuca) in different proportions: 0; 2; 10; 20 tons.ha-1 Planting pot area 0.042 m2, soil weight in each pot is 0.35 kg, each pot sows mustard seeds, after days remove and keep healthy plants All treatments were chemically fertilized at the recommended rate of 70-5035 kg N-P-K.ha-1 (Thi and Hung, 2005) Fertilize at stages 12, 19 and 26 days after planting Monitor and record growth indicators Collect samples of N2O and CH4 at weeks 1, 2, 3, and after planting Sampling method The gas sample collection method was carried out according to the method of Parkin et al., (2003) Sampling frequency was once per week Sampling time is fixed between am and 11am Sampling steps include: Take a large sample (right after placing the gas chamber), t1, t2 at time points after 10 minutes, 20 minutes with the same sampling method as the large sample After taking samples, record the temperature parameters at the time of sampling on the monitoring sheet The CH4 and N2O 10 concentrations were determined by gas chromatography (SRI 8610C) equipped with a flame ionization detector (FID) and an electron capture detector (ECD) 3.3.4 Calculating and processing data The intensity of CH4 or N2O emissions (mg/m2/hour) was calculated according to the following formula of Parkin et al., (2003) Where: ∆C is the change in concentration of CH4 or N2O in the time period ∆t; V and A are the volume of the gas sample box and the area of the bottom of the gas measuring box; M is the atomic mass of that gas; V is the volume occupied by mole of gas at standard temperature and pressure (22.4 L); P is atmospheric pressure (mbar), P0 is standard pressure (1,013 mbar); Tkelvin: 273 + Ttb; Ttb = (T0 + T1 + T2 + T3)/4 Total CH4 emissions were calculated based on the following formula of Parkin et al., (2003) = − × + − × +⋯ − × Where: n1, n2, n3 is the date of the 1st, 2nd and 3rd sampling; nx is the x sampling date before the last sampling, nc is the date of the last sampling, and Fn1, Fn2, Fn3, Fnx, Fnc are the daily average emissions of CH4 (mg.m-2) day-1) corresponding to the sampling dates n1, n2, n3, nx and nc Based on the calculation of the IPCC (2007), global warming potential is calculated by converting all gases to CO2 equivalents (CO2eq): N2O conversion factor to: CO2eq = N2O × 298 CH4 conversion factor to: CO2eq = CH4 * 25 (3.12) The total amount of greenhouse gas emissions is calculated according to the following formula: 11 GWP (kg CO2eq.ha-1 )= CH4 emissions * 25 + N2O emissions × 298 (3.13) CHAPTER 4: RESEARCH RESULTS 4.1.RESEARCH RESULTS CONTENT PHYSICALCHEMICAL PROPERTIES OF BIOCHAR MADE FROM BAMBOO AND MELALEUCA Bamboo and melaleuca biochar fired at 700ºC have a porous structure, with a specific surface area (BET) of 357.5 and 283.9 m2.g-1, respectively In addition, biochar of bamboo and melaleuca also has a CEC in the range of 14.34 - 15.12 cmolc.kg-1 and contains OH, and COOH functional groups In addition, biochar of bamboo and melaleuca has low EC (less than 246 µS.cm-1), very little ash (14%), and dissolved salt is less than 76 g.kgdb-1 The pHpzc values of bamboo biochar and melaleuca biochar are 6.67 and 6.47, respectively Biochar with these properties has the potential to become a good adsorbent and help reduce greenhouse gas emissions while not affecting plant growth 4.2 RESEARCH RESULTS CONTENT IDENTIFY THE NUTRITIONAL ASSISTANCE OF BASE BIOCHAR, TRAFFIC CHARACTERISTICS 4.2.1 Identify on ammonium adsorption capacity of bamboo biochar, and melaleuca biochar 4.2.1.1 Effect of solution pH on ammonium adsorption capacity Solution pH is an important factor affecting ammonium adsorption on biochar The amount of NH4+ adsorbed by biochar increased as the solution pH increased However, in the range of pH 5, the amount of NH4+ adsorbed biochar was very low, only 0.12-0.36 mg.g-1 When pH is reached, NH4+ adsorption capacity increases dramatically and reaches its maximum at pH = The maximum amount of ammonium adsorbed by bamboo biochar and melaleuca in wastewater after biogas can reach 12 1.85 mg.g-1and the highest adsorption efficiency was 50.62% (p