Granular Activated Carbons from Agricultural By-products: Preparation, Properties, and Application in Cane Sugar Refining (Bulletin #869)

The objectives of this investigation were to convert select Louisiana agricultural by-products to GAC and to characterize these carbons in terms of those physical (surface area, pore structure) and chemical (surface charge, functional groups) properties directly related to adsorption of raw sugar colorants.https://digitalcommons.lsu.edu/agcenter_bulletins/1038/thumbnail.jp

Granular Activated Carbon From Agricultural By-Products: Carbon Properties and Their Relationship to Sugar Decolorization Potential.

Representative samples of soft, low density, group 1 (rice straw, rice hulls, sugarcane bagasse) and hard, high density, group 2 agricultural by-products (pecan shells) were converted into granular activated carbons (GACs). Prior to pyrolysis, group 1 by-products were mixed with four binders, sugarcane molasses, sugar beet molasses, corn syrup and coal tar. GACs were produced from group 1 and 2 materials by physical activation (carbon dioxide, steam) or from group 2 materials by chemical activation (phosphoric acid). Carbons were evaluated for their physical (hardness, bulk density), chemical (ash, pH), surface (total surface area, pore size distribution, surface oxides) and adsorption properties (molasses color removal, sugar decolorization). Principal component and cluster analyses were used to compare agricultural by-product-based GACs to two commercial reference carbons. The results show that the type of by-product, binder and activation method determine the properties of activated carbons, with surface properties being the most influential on the decolorizing capacity of GACs. Combination of sugarcane or sugar beet molasses with group 1 materials, for instance, was unsatisfactory because it yielded GACs that were brittle and possessed low surface area, low bulk density, high pH and excessive ash content. The use of coal tar yielded GACs with good physical, chemical and surface properties, but with very limited surface area and, thus poor adsorption efficiency. Regardless of the binder, sugarcane bagasse showed a better potential than rice straw or rice hulls as precursor of GACs with the desirable properties of a sugar decolorizing carbon. Pecan shells produced GACs that were closest to the reference carbons. Steam and phosphoric acid activation showed promise in producing GACs with characteristics similar to the commercial carbons. Steam activation of pecan shells produced the best carbon among the agricultural by-product-based GACs and produced GAC with high surface area, good pore size distribution and weakly charged surface, which are good characteristics for sugar decolorizers. This study demonstrated that agricultural by-products can be used to produce GACs that are as effective as the commercial carbons in removing sugar colorants, offering a potential low cost alternative to the existing coal-based commercial carbons used in the sugar refining industry

Lipase and Lipoxygenase Activity, Functionality, and Nutrient Losses in Rice Bran During Storage (Bulletin #870)

This bulletin includes information on the feasibility of using microwave heat to inactivate lipase and LOX, determine the optimum storage and packaging conditions with the fewest adverse effects on functionality, and to determine changes in functionality of rice bran as a result of heat treatment.https://digitalcommons.lsu.edu/agcenter_bulletins/1031/thumbnail.jp

Biochars From Solid Organic Municipal Wastes For Soil Quality Enhancement

The overall municipal organic waste in Qatar accounts for 57% of municipal waste generated annually. Organic solid wastes such as food, newspapers, packaging, furniture woods and wood from building demolition have traditionally been placed in landfill, which create issues of sustainability for a country like Qatar with small land mass. While the recently opened Doha solid waste treatment facility contributed to alleviating the pressure on Landfill sites through composting and incineration, new value-added use of solid organic waste are needed for environmental and economic sustainability. Fortunately, biochars from mixed organic solid wastes can be used in soil amendment for food security and long term carbon sequestration for environmental sustainability. We hypothesize that deficiencies in depleted Qatari soils can be remedied by the application of biochars that are custom-designed to possess the right physicochemical characteristics suitable to improve soil fertility. Hence, this study was conducted to (1) Optimize production of biochars from mixed organic waste for desired physicochemical characteristics as soil enhancers. (2) Produce and characterize designer biochars using optimum production conditions for testing in soil incubation experiments. Select municipal organic wastes (newspaper, cardboard, woodchips and landscaping residues) individually and in a 25% blend were used as a precursor for biochar preparation. These residues were chosen due to their commonality in municipal solid waste streams. A complete 5 × 3 × 3 factorial design was used in this study with five biochar precursors (the 4 solid waste materials and a 25% blend/mixture), 3 sets of pyrolysis temperatures (350, 500, and 750°C) and 3 sets of pyrolysis residence time (2, 4 and 6 hrs). Data obtained showed that biochar yield was in the range of 21- 62% across all feedstocks and pyrolysis conditions. The highest yield was observed in newspaper-based biochars pyrolized at 350°C for 2 hrs. Key parameters such as pH, electrical conductivity bulk density and surface area, which positively improve water and nutrient-holding capacity in biochar-amended soil, varied depending on the precursors and production conditions. Bulk density was high in woodchips-based biochars but was similar among all other biochars, irrespective of precursors and pyrolysis conditions. The total surface area of biochars was low but showed dramatic increase in all feedstocks at 700°C pyrolysis temperature. The highest electrical conductivity observed in cardboard-based biochars pyrolized at 700C. Biochars produced from selected waste precursors were acidic except those produced at 700°C temperature where pH became alkaline. The wide range of biochar pH suggests potential tailoring to remediate the specific soil acidity. Cumulatively, biochars showed promising results for improving soil fertility parameters such as better water holding capacity, pH stabilization, and increased electrical conductivity of soil for better aggregation. These findings indicate that solid organic municipal wastes hold promising potential as precursors for manufacturing of value-added biochars with varied physicochemical characteristics allowing them to be used not only as an alternative to bio-waste management and greenhouse gas mitigation but also as means to improve depleted Qatari soil as the country embarks on its ambitious goals of ensuring food security and environmental sustainability.qscienc

Arab female and male perceptions of factors facilitating and inhibiting their physical activity: Findings from a qualitative study in the Middle East

Objectives: Physical inactivity is a leading global risk to health by contributing to obesity and other chronic diseases. Many chronic non-communicable diseases, such as cancer, diabetes, and cardiovascular diseases (CVDs), can be prevented and controlled by modifying lifestyle behaviors such as physical activity [PA]. However, prevalence of insufficient physical activity and obesity is high in the Middle East Region. In Qatar, the incidence rates of CVDs, diabetes, colon, and breast cancer have been rising rapidly. The purpose of this study was to explore facilitators and barriers influencing PA of adult Arab men and women living in Qatar and to understand what they think would be helpful to increase PA. The goal of the research is to identify culturally appropriate and effective interventions that improve the health of Arab population. Design: Using the socioecological model as the theoretical framework, we conducted an exploratory qualitative study with 128 Arab adult men and women living in Qatar. We utilized focus group interviews to collect the data and performed thematic analysis to generate themes. Results: At the individual level, perceived benefits of PA, presence of diseases, person’s will, motivation and goals, and time to exercise influenced the individual’s PA. At the sociocultural level, religious teachings of Islam, cultural, attitude, beliefs, and practices, and informal support influenced the participants’ PA. At the organizational and political level, physical environment to exercise, accessibility of facilities, organizational support, and health information about PA influenced their PA. Conclusion: Arab men and women are aware of the importance and benefits of PA. They have the motivation to be physically active, but in the absence of supportive environment, their knowledge might not translate into action. Creating supportive environments at multiple levels that are conducive to PA is warranted

Bioactive Components from Ginger, Tea and Apple Prevent Protein Glycation by Trapping Methylglyoxal with Potential in Alleviation of Diabetic Complications

Diabetes is the fifth-deadliest disease in the United States. Most diabetes patients die from diabetic complications, such as renal failure, heart attack or stroke. However, diabetic complications are still neither preventable nor curable. New strategies that can prevent, treat, or cure diabetic complications are needed. Increasing evidence has identified the formation of advanced glycation end products (AGEs) as a major pathogenic link between hyperglycemia and diabetes-related complications. In diabetes, formation of AGEs occurs at a higher rate when compared to non-diabetic normal individuals. Alpha-oxoaldehydes such as methylglyoxal (MGO) and glyoxal (GO), the reactive dicarbonyl intermediates generated during the non-enzymatic glycation between reducing sugars and amino groups of proteins, lipids, and DNA, are precursors of AGEs and exert direct toxicity to cells and tissues. Levels of MGO and GO were observed to be 2-6 times higher in diabetic patients' plasma as compared with healthy people's plasma. In addition, this is complicated by many food products and beverages representing exogenous sources of MGO and GO. It is likely that decreasing the levels of MGO and GO and inhibiting the formation of AGEs will form an important component of future therapy in patients with diabetes. Numerous studies have reported that bioactive components in ginger, tea and apple can prevent diabetes and its related complications. However, the underlying molecular mechanisms are still largely unknown. In this project, we investigated the effect of bioactive compounds in ginger ([6]-shogaol (6S) and [6]-gingerol (6G)), tea (epigallocatechin gallate (EGCG)) and apple (phloretin and phloridzin) to inhibit the formation of AGEs via trapping MGO. We demonstrated for the first time that both [6]-shogaol (6S) and [6]-gingerol (6G), the major active components in ginger, markedly trapped MGO in vitro and consequently formed mono-MGO adducts, 6S-MGO and 6G-MGO, which were purified from the respective chemical reaction and characterized as novel compounds by NMR experiments and LC-MS/MS approaches. We revealed that the ?-carbon of carbonyl group in the side chain of 6S or 6G is the major active site for trapping MGO. We also demonstrated that 6S and 6G could effectively inhibit the formation of MGO-induced AGEs via trapping MGO in a time-dependent manner in the human serum albumin (HSA)-MGO system. Mono-MGO adducts, 6S-MGO and 6G-MGO, were determined to be the major conjugates in 6S- and 6G-treated HSA-MGO assays, respectively, using LC-ESI/MS techniques. These findings showed the potential effects of 6S and 6G on the prevention of protein glycation, suggesting regular consumption of ginger root extract may attenuate the progression of MGO-associated diabetic complications in patients. Similarly, we found that both EGCG and phloretin could inhibit the formation of AGEs through the same pathways. In addition, we also studied whether these compounds could inhibit the formation of AGEs via trapping MGO in high fat diet treated mice. Two different doses of 6G, EGCG and phloretin (25 mg/kg and 75 mg/kg) were given to mice through oral gavage for 16 weeks. Plasma and tissue samples were collected from control and treated mice. The formation of MGO adducts of each compound were analyzed using our established LC/MS methods. The levels of MGO and AGEs were also quantified.qscienc

Biochars impact on soil moisture storage in an Ultisol and two Aridisols

Excessive copper concentrations in water systems can negatively impact biological systems. Because copper can form strong associations with organic functional groups, we examined the ability of biochar (a carbon-enriched organic bioenergy by-product) to sorb copper from solution. In a batch experiment, potassium hydroxide-steam activated pecan shell biochar was shaken for 24 hours in pH 6, 7, 8, or 9 buffered solutions containing various copper concentrations to identify effect of pH on biochar copper sorption. Afterwards, all biochar solids from the 24 hours shaking period were air-dried and then analyzed using X-ray absorption fine structure spectroscopy to determine solid-phase copper speciation. In a separate batch experiment, biochar was shaken for 30 days in pH 6 buffered solution containing increasing copper concentrations; the copper sorption maximum was calculated based on the exponential rise to a maximum equation. Biochar sorbed increasing amounts of copper as the solution pH decreased from 9 to 6. The X-ray absorption fine structure results revealed that copper was predominantly sorbed onto a biochar organic phase at pH 6 in a molecular structure similar to copper adsorbed on humic acid. The X-ray absorption fine structure spectra at pH 7, 8, and 9 suggested that copper was associated with the biochar as three phases: 1) a complex adsorbed on organic ligands similar to copper on humic acid; 2) carbonate phases similar to azurite; and 3) a copper oxide phase like tenorite. The exponential rise equation fit to the incubated samples predicted a copper sorption maximum of 42,300 mg/kg copper. The results showed that potassium hydroxide-steam activated pecan shell biochar could be utilized as a material for sorbing excess copper from water systems, potentially reducing the negative effects of copper in the environment

Switchgrass Biochar Effects Two Aridisols

The use of biochar has received growing attention with regards to improving the physico-chemical properties of highly weathered Ultisols and Oxisols, yet very little research has focused on effects in Aridisols. The objective of this study was to investigate the effect of either low or high temperature (250 or 500C) pyrolyzed switchgrass biochar on two Aridisols. In a pot study, biochar was added at 2% w/w to either a Declo loam (Xeric Haplocalcids) or a Warden very fine sandy loam (Xeric Haplocambids) and then incubated at 15% moisture content (by weight) for 127 days; a control (no biochar) was also included. Soils were leached with 1.2 to 1.3 pore volumes of deionized water on days 34, 62, 92, and 127, and cumulative leachate Ca, K, Mg, Na, P, Cu, Fe, Mn, Ni, Zn, NO3-N, NO2-N, and NH4-N concentrations were quantified. After the incubation experiment had terminated, soils were destructively sampled for extractable Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Zn, NO3-N, and NH4-N, total C, inorganic C, organic C, and pH. As compared to the 250C, the 500C pyrolysis temperature resulted in greater biochar surface area, elevated pH, higher ash content, and minimal total surface charge. For both soils, leachate Ca and Mg decreased with the 250C switchgrass biochar likely due to binding by biochar’s functional group sites. Both biochars caused an increase in leachate K, while the 500C biochar increased leachate P. The 500C biochar reduced leachate NO3-N concentrations as compared to the control; however, the 250C biochar reduced NO3-N concentrations to the greatest extent. Easily degradable C, associated with the 250C biochar’s structural make-up, likely stimulated microbial growth which caused NO3-N immobilization. Soil extractable K, P, and NO3-N followed a pattern similar to the leachate observations. Total soil C content increases were linked to an increase in organic C from the biochars. Cumulative results suggest that the use of switchgrass biochar prepared at 250C could improve environmental quality in calcareous soil systems by reducing nutrient leaching potential