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Arsenic Sorption by Iron Impregnated Biochar

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Much of Nepal lacks access to clean drinking water, and many water sources are contaminated with arsenic at concentrations above both World Health Organization and local Nepalese guidelines. While many

Much of Nepal lacks access to clean drinking water, and many water sources are contaminated with arsenic at concentrations above both World Health Organization and local Nepalese guidelines. While many water treatment technologies exist, it is necessary to identify those that are easily implementable in developing areas. One simple treatment that has gained popularity is biochar—a porous, carbon-based substance produced through pyrolysis of biomass in an oxygen-free environment. Arizona State University’s Engineering Projects in Community Service (EPICS) has partnered with communities in Nepal in an attempt to increase biochar production in the area, as it has several valuable applications including water treatment. Biochar’s arsenic adsorption capability will be investigated in this project with the goal of using the biochar that Nepalese communities produce to remove water contaminants. It has been found in scientific literature that biochar is effective in removing heavy metal contaminants from water with the addition of iron through surface activation. Thus, the specific goal of this research was to compare the arsenic adsorption disparity between raw biochar and iron-impregnated biochar. It was hypothesized that after numerous bed volumes pass through a water treatment column, iron from the source water will accumulate on the surface of raw biochar, mimicking the intentionally iron-impregnated biochar and further increasing contaminant uptake. It is thus an additional goal of this project to compare biochar loaded with iron through an iron-spiked water column and biochar impregnated with iron through surface oxidation. For this investigation, the biochar was crushed and sieved to a size between 90 and 100 micrometers. Two samples were prepared: raw biochar and oxidized biochar. The oxidized biochar was impregnated with iron through surface oxidation with potassium permanganate and iron loading. Then, X-ray fluorescence was used to compare the composition of the oxidized biochar with its raw counterpart, indicating approximately 0.5% iron in the raw and 1% iron in the oxidized biochar. The biochar samples were then added to batches of arsenic-spiked water at iron to arsenic concentration ratios of 20 mg/L:1 mg/L and 50 mg/L:1 mg/L to determine adsorption efficiency. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated an 86% removal of arsenic using a 50:1 ratio of iron to arsenic (1.25 g biochar required in 40 mL solution), and 75% removal with a 20:1 ratio (0.5 g biochar required in 40 mL solution). Additional samples were then inserted into a column process apparatus for further adsorption analysis. Again, ICP-MS analysis was performed and the results showed that while both raw and treated biochars were capable of adsorbing arsenic, they were exhausted after less than 70 bed volumes (234 mL), with raw biochar lasting 60 bed volumes (201 mL) and oxidized about 70 bed volumes (234 mL). Further research should be conducted to investigate more affordable and less laboratory-intensive processes to prepare biochar for water treatment.

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  • 2021-05

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Biochar production methods and its use for water filtration in less developed settings

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After visiting Nepal and seeing the problem of potable drinking water, there needed to be a solution to purify it. Simultaneously, local national forests have been overrun with two invasive

After visiting Nepal and seeing the problem of potable drinking water, there needed to be a solution to purify it. Simultaneously, local national forests have been overrun with two invasive plant species: Mikania micrantha and Lantana camara. Both a very fast-growing species and can be turned into biochar. If the resulting is made through an effective process, then the community would be able to work less making each batch of biochar and make more money per batch, whereby the market already exists. The community could grow their profits even further by activating the created charcoal, which fetches an even better price. Most Importantly, among other important uses, the activated charcoal could also be used in clean drinking water systems. The prospect of using activated charcoal as water purifying agents can be tested in a future design of experiments. This design of experiments would assess the effectiveness of the activated charcoal, to determine which pore size is the most cost effective at filtering out pollutants. This thesis focuses on researching different types of biochar kilns, clean drinking water systems, and the use of charcoal in clean drinking water systems.

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  • 2018-05

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Can Biochar Be Converted into Activated Carbon?

Description

In Nepal, a viable solution for environmental management, food and water security is the production of biochar, a carbon material made of plants burned in low oxygen conditions. Currently, the

In Nepal, a viable solution for environmental management, food and water security is the production of biochar, a carbon material made of plants burned in low oxygen conditions. Currently, the biochar is manufactured into charcoal briquettes and sold on the market for energy usage, however this may not provide the best value for community members who make less than a dollar a day and sell the biochar for as little as 16 cents per kilogram. This thesis seeks to improve the price of biochar and help their livelihoods as well as explore innovative solutions. One way to improve biochar while addressing water security problems is to create activated carbon, which uses its heightened porosity to adsorb contaminants from water or air. Activated carbon is also worth 100x the price of biochar. This thesis evaluates the mass content of biochar produced in Nepal, comparing it to literature values, and performed gravimetric and thermogravimetric analysis, comparing it to Activated Charcoal. Analysis of the biochar system used in Nepal reveals that the byproduct of biochar, biofuels, is highly underutilized. The higher heating value of biochar is 17.95 MJ/kg, which is much lower than other charcoals which burn around 30 MJ/kg. Low volatile content, less than 5% in biochar, provides a smokeless briquette, which is favorable on the market, however low heating value and misutilizations of biofuels in the solution indicate that creating a briquette is not the best use for biochar. Ash content is really high in this biochar, averaging around 12% and it may be due to the feedstock, a composite between Mikania and Lantana, which have 5.23% and 10.77% ash content respectively. This does not necessarily indicate a poor quality biochar, since ash values can vary widely between charcoals. Producing activated charcoal from this biochar is a favored solution; it will increase the price of the biochar, provide water security solutions, and be an appropriate process for this biochar, where heating value and underutilization of biofuel byproducts pose a problem.

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  • 2019-05

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FROM SUBSISTENCE TO SURPLUS: HELPING FARMERS IN RURAL PERU TO INCREASE CROP PRODUCTION BY IMPROVING SOILS

Description

"Seventy five percent of the world's poor live in rural areas of developing countries, where most people's livelihoods rely directly on agriculture." (USAid, 2014) Reduced levels of crop production and

"Seventy five percent of the world's poor live in rural areas of developing countries, where most people's livelihoods rely directly on agriculture." (USAid, 2014) Reduced levels of crop production and the accompanying problems of malnourishment exist all over the world. In rural Peru, for example, 11 percent of the population is malnourished. (Global Healthfacts.org, 2012) Since the success in agriculture relies importantly on the fertility of the soil, it is imperative that any efforts at reversing this trend be primarily directed at improving the existing soils. This, in turn, will increase crop yields, and if done properly, will also conserve natural resources and maximize profits for farmers. In order to improve the lives of those at the bottom of the pyramid through agriculture, certain tools and knowledge must be provided in order to empower such persons to help themselves. An ancient method of soil improvement, known as Terra Preta do Indio (Indian dark earth), was discovered by Anthropologists in the 1800's. These dark, carbon-rich, soils are notable for their high fertility, high amounts of plant available nutrients, and their high moisture retention rates. The key to their long-lasting fertility and durability is the presence of high levels of biochar, a highly stable organic carbon \u2014 produced when organic matter (crop residues, food waste, manure, etc.) is burned at low temperatures in the absence of oxygen. Research has shown that when charcoal (biochar) and fertilizers are combined, it can yield as much as 880 percent more than when fertilizers are used by themselves. (Steiner, University of Bayreuth, 2004)

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  • 2014-12

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Design and Optimization of Nepalese Biochar Furnaces

Description

This thesis sought to better understand the process of creating biochar in kilns representative of those used in current biochar processes in Chitwan National Park, Nepal and surrounding areas. The

This thesis sought to better understand the process of creating biochar in kilns representative of those used in current biochar processes in Chitwan National Park, Nepal and surrounding areas. The project had two main objectives: First, design and build a scale kiln representative of those in Nepal. This will allow a multitude of future projects to have access to a well-built kiln in which to run experiments, probe conditions and overall understand the process of pyrolysis. After approval of the plan and construction the second phase of the project began. Second, using the scaled kiln, pyrolyze quantities of biomass and capture the temperature profiles as the burn is started through until it is completed. Using qualitative methods the biochar was then analyzed and this quality compared against the temperature profiles captured. Using these profiles it was hoped that a relationship between how the temperature profiles behave and the quality of the biochar can be produced. The maximum temperature was also be analyzed to find useful correlations to the behavior of the process within the kiln. The project did not find any useful correlation between the maximum temperatures, but it did find useful correlations between temperature profiles and the resulting biochar. A description of how to analyze biochar in the field was also established to help researchers and farmers rate biochar quality while in the field. The kiln itself is housed on the Polytechnic Campus of Arizona State University in the Global Resolve outside storage area at the time of writing.

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Date Created
  • 2018-12

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An analysis of biochar's appropriateness and strategic action plan for its adoption and diffusion in a high poverty context: the case of central haiti

Description

Haiti has witnessed high deforestation rates in recent decades, caused largely by the fuel needs of a growing population. The resulting soil loss is estimated to have contributed towards a

Haiti has witnessed high deforestation rates in recent decades, caused largely by the fuel needs of a growing population. The resulting soil loss is estimated to have contributed towards a decline in agricultural productivity of 0.5% -1.2% per year since 1997. Recent studies show the potential of biochar use through pyrolysis technology to increase crop yields and improve soil health. However, the appropriateness of this technology in the context of Haiti remains unexplored. The three objectives of this research were to identify agricultural- and fuel-use-related needs and gaps in rural Haitian communities; determine the appropriateness of biochar pyrolyzer technology, used to convert agricultural biomass into a carbon-rich charcoal; and develop an action-oriented plan for use by development organizations, communities, and governmental institutions to increase the likelihood of adoption. Data were collected using participatory rural appraisal techniques involving 30 individual interviews and three focus-group discussions in the villages of Cinquantin and La Boule in the La Coupe region of central Haiti. Topics discussed include agricultural practices and assets, fuel use and needs, technology use and adoption, and social management practices. The Sustainable Livelihoods framework was used to examine the assets of households and the livelihood strategies being employed. Individual and focus group interviews were analyzed to identify specific needs and gaps. E.M. Rogers' Diffusion of Innovations theory was used to develop potential strategies for the introduction of pyrolysis technology. Preliminary results indicate biochar pyrolysis has potential to address agricultural and fuel needs in rural Haiti. Probable early adopters of biochar technology include households that have adopted new agricultural techniques in the past, and those with livestock. Education about biochar, and a variety of pyrolysis technology options from which villagers may select, are important factors in successful adoption of biochar use. A grain mill as an example in one of the study villages provides a model of ownership and use of pyrolysis technology that may increase its likelihood of successful adoption. Additionally, women represent a group that may be well suited to control a new local biochar enterprise, potentially benefiting the community.

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Date Created
  • 2011

Biochar Briquettes: Alternative to Firewood and Charcoal Fuel

Description

Domestic energy is an important component of our day to day lives and is something we cannot live without. Imagine how life would be without a means to cook our

Domestic energy is an important component of our day to day lives and is something we cannot live without. Imagine how life would be without a means to cook our food, to warm our house, life would be unbearable. As we enjoy these comforts rarely do we stop to think what the opportunity cost is. For those using renewable sources, it is not a big issue, but for those who rely on wood fuel, they have to strike a delicate balance between need for fuel and the need to conserve the greatest support systems of their livelihoods, the forests. The main source of energy for households in many developing countries is biomass, mainly from forests and woodlands. The continued use of firewood and charcoal fuel puts a strain on forests, resulting in adverse effects on the environment such as prolonged droughts, loss of biodiversity, dwindling water resources, changing weather patterns among other sustainability challenges. An alternative to firewood to charcoal lies in biochar briquettes. This paper discusses the role of biochar briquettes in mitigating climate change and serves as a step by step guide on how biochar briquettes may be produced.

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  • 2018