Adsorption of phosphate onto agricultural waste biochars with ferrite/manganese modified-ball-milled treatment and its reuse in saline soil.

Agricultural waste biochar was widely used to absorb phosphorus (P) from eutrophicated water and soil remediation. However, the research on the reuse of the sorbed P on biochar in infertile saline soil is insufficient. Biochars derived from four kinds of agricultural wastes (cotton straws from two origins, maize stalk, and rice husk) were modified and applied to adsorb phosphate in waste water and then be reused in saline soil in this study. The co-modified method combining ball milling and metal coated treatment obtained the higher specific surface area (SSA) of ferrite/manganese modified-ball-milled biochars (Fe/Mn-BMBCs) (226.5-331.5 m2 g-1) than that of pristine biochars (14.02-30.35 m2 g-1) and ferrite/manganese modified biochar (Fe/Mn-BC) (223.7 m2 g-1), which could improve the pore structure of metal modified biochar. The phosphate adsorption capacity (qmax) of Fe/Mn-BMBCs with rich functional groups and high SSA were 44.0-53.8 mg g-1, which was 4.47-5.82 times higher than that of pristine biochars. Fe/Mn-BMBCs showed efficiently adsorption performance at low pH and high temperature. The application of BC to saline soil could promote the availability of P in saline soil. P-loaded biochars could afford P as a nutrient to promote the growth of lettuce (Lactuca sativa L.) in saline soil. The lettuce fresh weight in Fe/Mn-BMBC-P2 treated soil was 8.21 times higher than that grew in control check (CK) treatment. As a P element provider, P-loaded biochars not only improve saline soil fertility and crop productivity, but also convert the agricultural wastes and P in eutrophicated waters to the sustainable resource.

Potential of Low Cost Agro-Industrial Wastes as a Natural Antioxidant on Carcinogenic Acrylamide Formation in Potato Fried Chips.

Acrylamide is classified as a toxic and a prospective carcinogen to humans, and it is formed during thermal process via Maillard reaction. In order to find innovative ways to diminish acrylamide formation in potato chips, several extracts of agricultural wastes including potato peels, olive leaves, lemon peels and pomegranate peels extracts were examined as a soaking pre-treatment before frying step. Total phenolic, total flavonoids, antioxidant activity, and the reduction in sugar and asparagine contents were additionally performed. Proximate composition of these wastes was found to be markedly higher in fat, carbohydrate and ash contents. Lemon peels and potato peels showed almost similar phenolic content (162 ± 0.93 and 157 ± 0.88 mg GAE /g, respectively) and exhibited strong ABTS and DPPH radical scavenging activities than the other wastes. The reduction percentage of reducing sugars and asparagine after soaking treatment ranged from 28.70 to 39.57% and from 22.71 to 29.55%, respectively. HPLC results showed higher level of acrylamide formation in control sample (104.94 mg/kg) and by using the wastes extracts of lemon peels, potato peels, olive leaves, and pomegranate peels succeeded to mitigate acrylamide level by 86.11%, 69.66%, 34.03%, and 11.08%, respectively. Thus, it can be concluded that the soaking of potato slices in the tested wastes extracts as antioxidant as pre-treatment before frying reduces the formation of acrylamide and in this way, the risks connected to acrylamide consumption could be regulated and managed.

The effect of reactor scale on biochars and pyrolysis liquids from slow pyrolysis of coffee silverskin, grape pomace and olive mill waste, in auger reactors.

Several studies have addressed the potential biorefinery, through small-scale pyrolysis, of coffee silverskin (CSS), grape pomace (GP) and olive mill waste (OMW), which are respectively the main solid residues from coffee roasting, wine making and olive oil production processes. However, increasing the scale of reactor to bring these studies to an industrial level may affect the properties, and hence applications, of the resulting products. The aim of this study is therefore to perform pilot scale experiments to compare and verify the results of analytical study (TGA) and bench scale reactor runs, in order to understand the fundamental differences and create correlations between pyrolysis runs at different scales. To this end, pyrolysis liquids and biochars from the slow pyrolysis of CSS, GP and OMW, performed using different scale auger reactors (15 kg/h and 0.3 kg/h), have been analysed (TGA, pH, density, proximate and ultimate analyses, HHV, FTIR, GCMS) and compared. The results showed no major differences in biochars when the temperature and the solid residence time were fixed. However, regarding pyrolysis liquids, compounds from the lab reactor were more degraded than pilot plant ones, due to, in this case, the vapour residence time was longer. Regarding the properties of the pyrolysis products, GP 400 °C biochars showed the best properties for combustion; CSS biochars were especially rich in nitrogen, and 400 °C GP and OMW pyrolysis liquids showed the highest number of phenolics. Hence, this study is considered a first step towards industrial scale CSS, GP and OMW pyrolysis-based biorefinery.

Effectiveness of agricultural waste in the enhancement of biological denitrification of aquaculture wastewater.

Nitrogen pollution in aquaculture wastewater can pose a significant health and environmental risk if not removed before wastewater is discharged. Biological denitrification uses external carbon sources to remove nitrogen from wastewater; however, these carbon sources are often expensive and require significant energy. In this study, we investigated how six types of agricultural waste can be used as solid carbon sources in biological denitrification. Banana stalk (BS), loofah sponge (LS), sorghum stalk (SS), sweet potato stalk (SPS), watermelon skins (WS) and wheat husk (WH) were studied to determine their capacity to release carbon and improve denitrification efficiency. The results of batch experiments showed that all six agricultural wastes had excellent carbon release capacities, with cumulative chemical oxygen demands of 37.74-535.68 mg/g. During the 168-h reaction, the carbon release process followed the second-order kinetic equation and Ritger-Peppas equation, while carbon release occurred via diffusion. The kinetic equation fitting, scanning electron microscopy, and Fourier transform infrared spectroscopy results showed that LS had the lowest cm and the maximum t1/2 values and only suffered a moderate degree of hydrolysis. It also had the lowest pollutant release rate and cumulative chemical oxygen demand, as well as the most efficient removal of total phosphorous (TP) and total nitrogen (TN). Therefore, we concluded that LS has the lowest potential risk of excess carbon release and capacity for long-lasting and stable carbon release. The WS leachate had the highest TN contents, while the SPS leachate had the highest TP content. In the 181-h denitrification reaction, all six agricultural wastes completely removed nitrate and nitrite; however, SS had the highest denitrification rate, followed by LS, WH, BS, SPS, and WS (2.16, 1.35, 1.35, 1.34, 1.34, and 1.01 mg/(L·h), respectively). The denitrification process followed a zero-order and first-order kinetic equation. These results provide theoretical guidance for effectively selecting agricultural waste as a solid carbon source and improving the denitrification efficiency of aquaculture wastewater treatment.

Fabrication of lignin-containing cellulose bio-composite based on unbleached corncob and wheat straw pulp.

In contemporary life, plastic, a kind of petroleum carbon source, has been produced and used in varieties of applications. However, the vast consumption of petroleum-based plastic and the burning of agricultural wastes make the environmental problems increasingly severe. Furthermore, a large number of lignocellulosic resources (such as corncob and wheat straw) are often wasted and burned, which will aggravate the environmental damage. In this paper, we use unbleached corncob and wheat straw pulp to fabricate the lignin-containing cellulose bio-composites (LCBs) to reduce non-renewable energy consumption and utilize agricultural wastes. The LCBs were obtained by a direct manufacturing process in benzyltrimethyl ammonium hydroxide (BzMe3NOH) aqueous solution under mild conditions, constituting an entwined composite structure of cellulose micro/nano-fibers. This unique micro/nano-structure provides bio-composites with the outstanding mechanical performance of 96.7 MPa and a high haze of 90.1%. Meanwhile, with the inherent lignin, the LCBs could filter over 81.8% UV-C. As the raw material used is pure natural lignocellulose, the bio-composites prepared have innate environmental friendliness. With exceptional mechanical strength, UV-shielding property, and innate environmental friendliness, the LCBs are possible and potential substitutes for traditional petroleum-based plastic that is easily aging or non-biodegradable.

Implementation of graphitic carbon nitride nanomaterials and laser irradiation for increasing bioethanol production from potato processing wastes.

Agricultural and agro-industrial wastes (e.g., potato peel waste) are causing severe environmental problems. The processes of pretreatment, saccharification, and fermentation are the major obstacles in bioethanol production from wastes and must be overcome by efficient novel techniques. The effect of exposing the fungi (yeast) Saccharomyces cerevisiae to laser source with the addition of graphitic carbon nitride nanosheets (g-C3N4) with different concentrations on bioethanol production was investigated through the implementation of a batch anaerobic system and using potato peel waste (PPW). Dichromate test was implemented as quantitative analysis for quantification of the bioethanol yield. The benefits of this test were the appearance of green color indicating the identification of ethanol (C2H5OH) by bare eye and the ease to calculate the bioethanol yield through UV-visible spectrophotometry. The control sample (0.0 ppm of g-C3N4) showed only a 4% yield of bioethanol; however, by adding 150 ppm to PPW medium, 22.61% of ethanol was produced. Besides, laser irradiations (blue and red) as influencing parameters were studied with and without the addition of g-C3N4 nanomaterials aiming to increase the bioethanol. It was determined that the laser irradiation can trigger the bioethanol production (in case of red: 13.13% and in case of blue: 16.14% yields, respectively) compared to the control sample (in absence of g-C3N4). However, by adding different concentrations of g-C3N4 nanomaterials from 5 to 150 ppm, the bioethanol yield was increased as follows: in case of red: 56.11% and, in case of blue: 56.77%, respectively. It was found that using fungi and exposing it to the blue laser diode source having a wavelength of 450 nm and a power of 250 mW for a duration of 30 min with the addition of 150 mg L-1 of g-C3N4 nanomaterials delivered the highest bioethanol yield from PPW.

Development of an organomineral fertiliser formulation that improves tomato growth and sustains arbuscular mycorrhizal colonisation.

Achieving sustainable agricultural development requires the efficient use of nutrient resources for crop production. Recovering nutrients from animal manures may play a key role in achieving this. Animal manures typically have low nutrient concentrations, and in ratios that are often not ideal for balanced crop nutrition. Here, combinations of organic and inorganic phosphorus (P) were formulated as granular products (organomineral fertilisers) with granule size suitable for transport and spreading. The fertilisers were produced by granulating powdered chicken litter with MAP and urea powders making the following formulations: 0:4, 1:3, 2:2, 3:1, 4:0. The kinetics of NH4+-N and P release from the fertilisers, and the effects on tomato growth and nutrition, as well as arbuscular mycorrhizal formation in roots following fertiliser application, were determined. Cumulative NH4+-N release ceased within 12 h, and was lower in the formulations with higher proportions of chicken litter. The cumulative P released reached approximately 80% of total P in all formulations, and the time to obtain maximum P dissolution was 19 days in the formulation that contained only chicken litter. The organomineral fertilisers increased tomato shoot growth by 15-28% compared to the chicken litter only, MAP only and MAP/urea formulations. Reasonable levels of mycorrhizal colonisation of tomato roots was achieved with the organomineral fertilisers. The results demonstrated that optimum plant growth does not depend solely on immediately available P, and that timing of nutrient supply to match plant demand is important. The combination of chicken litter with MAP sustained nutrient supply and improved plant growth. Taken together, organomineral fertiliser formulations are potential alternatives to inorganic P fertilisers that can improve crop growth and nutrition, while provide a sustainable use for animal production wastes.

Contributions of the biochemical factors and bacterial community to the humification process of in situ large-scale aerobic composting.

Multiple types of biochemical parameters were determined in the course of the composting process with rice straw and Chinese traditional medicine residues as substrates. The water-soluble fractions (WSFs) were analyzed by excitation-emission-matrix fluorescence (EEM-FL), and the maximum PV/III value (1.2) was observed in thermophilic phase (THP). Bacterial community analysis results indicated that the genera with the capacity of degrading lignocellulose dominated in mesophilic phase (MEP) and THP. The metabolic pathways based on KEGG analysis revealed that the amino acid, carbohydrate and energy metabolism pathways in THP were higher than the other two phases. The correlation analysis between EEM-FL and the bacterial community revealed that the genera with high abundances in the THP were significantly positively correlated with fulvic acid-like materials and humic acid-like organics. The quantification results of the lignocellulose-degrading genes in different phases further verified the key functional bacteria obtained by correlation analysis during the composting process.

Sulfur bentonite-organic-based fertilizers as tool for improving bio-compounds with antioxidant activities in red onion.

BACKGROUND: Red onion is popular in cuisines worldwide and is valued for its potential medicinal properties. Red onion is an important source of several phytonutrients such as flavonoids, thiosulfinates and other sulfur compounds, recognized as important elements of the diet. Nowadays, there is the need of producing food enriched in health benefit compounds. In this study, pads of sulfur bentonite (SB) with the addition of orange residue (OR) or olive pomace (OP) were used to improve the quality of red onion. The experiment was conducted for 3 months in the field to evaluate the phytochemicals of differently amended red onion. RESULTS: Treated plants were better in quality than controls. Antioxidant activity, detected as DPPH, ORAC and ABTS, was highest in plants grown in the presence of SB enriched with agricultural wastes, particularly SB-OR. Polyphenols increased in all treated plants. The volatile fraction was clearly dominated by sulfur compounds that are strictly related to the concentration of the aroma precursors S-alkenyl cysteine sulfoxides. The greater amount of thiosulfinates in treated compared with untreated onion evidenced that SB pelletized with agricultural wastes can represent a new formulation of organic fertilizer able to improve the beneficial properties of onion. The results highlighted that the best red onion quality was obtained using SB-OR pads. CONCLUSION: The use of SB bound with agricultural wastes represents a novel strategy to increase bio-compounds with beneficial effects on human health, to enhance the medical and economic values of sulfur-loving crops, with important consequences on the bio and green economy. © 2019 Society of Chemical Industry.

Utilization of Ficus carica leaves as a heterogeneous catalyst for production of biodiesel from waste cooking oil.

Biodiesel appears to be a possible substitute for non-renewable fossil fuels; however, its production requires the presence of a catalyst to accelerate the reaction. Serving the purpose of finding effective, cheap and environmentally safe, heterogeneous catalysts, this research used the fig leaves in three different forms, calcined, activated by KOH, and activated by both K2CO3 and CaCO3. Their efficiency in biodiesel synthesis, from spent cooking oil, was examined and compared with that of activated carbon which has been previously investigated. The properties of different catalyst forms were specified using X-ray diffraction, scanning electron microscope and Fourier transform infrared spectroscopy. Operating parameters studied for the three catalysts were reaction time (from 30 to 180 min), alcohol-to-oil molar ratio (from 4:1 to 10:1), catalyst loading (from 0.5 to 5% by wt.), and stirring speed (from 100 to 400 rpm). The increase in reaction time, molar ratio, and catalyst loading proved to have a favorable effect on % conversion to biodiesel but to a certain degree; increasing the stirring speed augmented the conversion. At optimum conditions (2 h of heating, 6:1 alcohol-to-oil molar ratio, 1% by wt. catalyst loading, and 400 rpm stirring), fig leaves activated by KOH provided the highest conversion to biodiesel (92.73%). The measured properties of the produced biodiesel (density, viscosity, flash point, cloud point, and pour point) yielded encouraging results. Graphical Abstract.

Toxicological studies for some agricultural waste extracts on mosquito larvae and experimental animals.

OBJECTIVE: To evaluate some agricultural waste extracts as insecticide and their effects on enzyme activities in liver and kidney of male mice. METHODS: The insecticidal activity of five tested compounds (one crude extract and 4 waste compounds) was bioassay against the 3rd instars of the Culex pipiens (Cx. pipiens) larvae in the laboratory. The LC50 values of eucalyptol, apricot kernel, Rice bran, corn, black liquor and white liquor are 91.45, 1 166.1, 1 203.3, 21 449.65, 4 025.78 and 6 343.18 ppm, respectively. Selection of the compounds for the subsequent studies was not only dependent on LC50 values but also on the persistence of these wastes products on large scale. RESULTS: White and black liquor did not produce any gross effect at 200 mg/Kg body weight. No apparent toxic symptoms were observed in tested animals during the whole period of the experiment which run out for 14 days. No statistically significance was observed in the enzyme cholinesterase activity, the activities of liver enzymes and kidney function in treated mice with black and white liquors. While, no and slight inhibition was observed after the 2 weeks of treatment period with deltamethrin and fenitrothion reached to about 24% in plasma cholinesterase enzyme activity. Significantly increase in the activities of liver enzymes and kidney function in treated mice with deltamethrin and fenitrothion. CONCLUSIONS: Black liquor can be used efficiently to control Cx. pipiens larvae under laboratory condition. Environmental problem caused by rice straw can be solved by converting the waste material to beneficial natural selective insecticide.