Inclusion Of Biochar Research Articles

Efficient Treatment of Wood Vinegar via Microbial Electrolysis Cell With the Anode of Different Pyrolysis Biochars

Microbial electrolysis cell (MEC) had a good performance during the treatment of bio-refractory wastewater. This study focused on wood vinegar (from biomass pyrolysis) treatment via MECs with biochar anode. The results indicated that MECs with coconut shell biochar as the anode had an obvious beneficial effect for treating wood vinegar. When wood vinegar was used as the substrate of MECs, COD removal reached up to 71.4%, and effluent COD was 359.0 mg COD/L. GC-MS analysis showed that furfurals present in the wood vinegar were thoroughly degraded after MEC treatment. One interesting finding is that hydrocarbons accounted for a large portion of the compounds in the effluent, which may be the comprehensive result of complex organic reactions, including decarboxylation reactions, dehydration reaction, etc. The dominant microbial populations in MEC with biochar anode mainly included Geobacter, Macellibacteroides, Oscillibacter, Sedimentibacter, Comamonas and Lachnoclostridium. In particular, Lachnoclostridium (3.34%), a new family of exoelectrogens, may be correlated with the degradation of wood vinegar. This study demonstrated that pyrolysis biochar could be incorporated as a high-efficiency MEC anode material, and MECs with the inclusion of biochar could provide a feasible way for the treatment of recalcitrant wood vinegar.

Effects of biochar on the chemical changes and phase separation of bio-asphalt under different aging conditions

Bio-asphalt replaced petroleum-asphalt for paving asphalt pavements, which is a technology with a wide range of application prospect. This work is aimed at improving the performance of aged bio-oil modified asphalt (bio-asphalt) for use in road pavement construction. Biochar and bio-oil are renewable resources and use in this research that are pyrolyzed from waste wood. The effects of different aging conditions on biochar-modified bio-asphalt and ordinary bio-asphalt were investigated in terms of their chemical functional groups, molecular formulas, radius distribution functions, rheological parameters, and phase separation. The aging conditions considered in this research are short-term aging, ultraviolet (UV) aging, pressure aging vessel (PAV), and low-temperature hardening. Biochar plays a significant role in the UV aging process. This study found that, with an increase in biochar modification, the alkyl group numbers increased and the sulfoxide and carbonyl numbers decreased during the aging process of bio-asphalt. It also shows that the inclusion of biochar improved the aging resistance of the bio-asphalt, but that biochar modification did not affect the bio-asphalt’s low-temperature hardening performance. Four asphalt components were studied: saturates, asphaltenes, resins, and aromatics (SARA). The effects of biochar on saturates and aromatics were significant, and the biochar was able to adsorb these components. This study also found that, with an increase in UV aging and PAV, the phase separation grows.

Biochar filled high-density polyethylene composites with excellent properties: Towards maximizing the utilization of agricultural wastes

Biochar derived from agricultural wastes was used to reinforce high-density polyethylene (HDPE) to obtain composites abbreviated as B10, B20, B30, B40, B50, B60, and B70. Investigating the mechanical, thermal, water absorption and flame retardant properties of the composites is one of the objectives while maximizing the utilization of agricultural wastes is the ultimate goal of this work. It was found that flexural properties, tensile properties, storage modulus, elasticity, creep resistance and anti-stress relaxation ability of HDPE were improved by the inclusion of biochar, and excellent mechanical properties were obtained in 50 % even 60 % biochar added composites because of good dispersion and unique structure shown in the interface. The composites achieved good flexural strength of 34.95 MPa in B50, flexural modulus of 1.79 GPa in B40, tensile strength of 29.05 MPa in B40, and tensile modulus of 2.03 GPa. Additionally, the thermal and flame retardant properties (limited oxygen index of 25.06 % in B70) increased for the biochar added composites as the biochar loading increased due to the high thermal stability of biochar, although biochar had a negative effect on water-resistance of the composites. The results revealed that the ultimate goal was achieved in terms of producing composites with excellent mechanical, thermal, water absorption and flame retardant properties while maximizing the utilization of agricultural wastes as a rational balance.

Biochar seeding promotes struvite formation, but accelerates heavy metal accumulation

This study investigated the effects of biochar seeding (wheat straw biochar and rice husk biochar) on nutrient recovery via struvite formation, and improvements in the particle size of precipitated struvite from anaerobic digestate supernatant. Simultaneously, the influence of biochar seeding on heavy metal accumulation and elimination of pathogens (total coliforms and Escherichia coli) was evaluated under various operational factors, e.g., pH, supersaturation, reaction time, and seeding rates. Compared to the non-seeding process (maximum recovery efficiency of phosphate and ammonium 91% and 83%, respectively, with a particle size of 70 μm) and the struvite-seeding process (maximum recovery efficiency of phosphate and ammonium 97% and 94%, respectively, with a particle size of 100 μm), the process of biochar seeding improved nutrient recovery up to 7% and 11% for phosphate and ammonium, respectively, and increased struvite particle size by 43%, regardless of biochar type. XRD diffraction and FTIR analysis confirmed the prevalence of orthorhombic characteristics and an inner crystalline structure of the struvite formed by biochar seeding. About 75% of total coliforms and 70% of Escherichia coli were removed from the digestate supernatant through seeded struvite precipitation, regardless of the seeding materials. However, the biochar seeding process led to an accumulation of heavy metals in the acquired struvite product than that with non-seeded precipitation process. The concentrations of these metals were still well below permissible limits for application on agricultural land. It can be concluded that the inclusion of biochar as a seeding material might be a sustainable strategy to enhance struvite formation, intensify nutrient recovery, and yield high-quality struvite fertilizer with increased particle sizes.

Effect of dietary inclusion of biochar on growth performance, haematology and serum lipid profile of broiler birds

One hundred and twenty (120) day-old broiler birds were used to ascertain the effect of dietary inclusion of biochar on the growth, hematology and serum lipid profiles of birds in a 56-day feeding trial. The birds were randomly assigned to 4 groups of 30 birds each, replicated twice with 15 birds per replicate. The groups were randomly assigned to four diets in a completely randomized design involving four levels (0, 2, 4 and 6%) of biochar kg -1 . Treatments did not differ significantly (P > 0.05) in final body weight, average daily weight gain, average daily feed intake and feed conversion ratio at the starter phase. However, at the finisher phase, significant differences (P 0.05) was observed in the triacylglycerol (TAG) values of birds at the finisher phase, while cholesterol and low density lipoprotein levels were significantly reduced (P < 0.05, 0.01) at both phases. The result of the present study showed that up to 6% dietary biochar kg -1 improved growth, hematology and serum lipid profiles of broiler birds. Keywords: biochar, performance, health-status, fat-accretion, broilers

Effect of biochar produced from different biomass sources and at different process temperatures on methane production and ammonia concentrations in vitro

The effects of different biochars on in vitro rumen gas production and fermentation characteristics were investigated using a two (biochar inclusion level, 10 and 100 g biochar/kg substrate) x two (process temperature, 550 or 700 °C) × five (biomass source, Miscanthus straw, oil seed rape straw, rice husk, soft wood pellets or wheat straw) factorial design. The amount of biochar included in incubations had no effect on in vitro fermentation. Overall, inclusion of biochar reduced total gas production to 0.96 (P < 0.001) and methane (CH4) production to 0.95 (P < 0.001) of that in control (no added biochar) incubations. There were no differences in gas or CH4 production between the biomass sources used to produce biochar but total gas (P = 0.058) and CH4 (P = 0.010) production were slightly greater when biochar was produced at 700 rather 550 °C. Addition of biochar to incubations did not change total amounts of volatile fatty acids (VFA) or acetic acid produced during in vitro fermentation; however, the amounts of propionate (0.94; P < 0.001) and butyrate (0.96; P = 0.021) were reduced when biochar was added to incubations. Process temperature had no effect on VFA produced; however, total VFA and the amounts of acetic and butyric acids produced were influenced by biochar biomass source. Ammonia concentrations at the end of incubations were overall 0.84 of control concentrations (P < 0.001)when biochar was added. Both process temperature and biochar biomass source influenced ammonia concentrations which were greater for biochar produced at 700 than 550 °C; concentrations were lowest for biochar produced from Miscanthus straw and greatest for rice husk with oil seed rape straw, soft wood pellets and wheat straw intermediate. Adding biochars with a range of compositions to in vitro assays produced only small reductions in CH4 production. However, the absence of any negative effects of biochar coupled with the observed reduction in ammonia concentrations makes it possible that including biochar in livestock feed could be a practical means of applying biochar to pasture and soil.

Impacts of straw biochar additions on agricultural soil quality and greenhouse gas fluxes in karst area, Southwest China

ABSTRACTUnderstanding and improving environmental quality by reducing soil nutrient leaching losses, sequestering carbon (C), reducing greenhouse gas (GHG) emissions, and enhancing crop productivity in highly weathered or degraded soils have always been the goals of agroecosystem researchers and producers. Biochar production and soil incorporation strategies have been recently proposed to help attain these goals. However, the effect of such approaches on soil GHG fluxes is highly uncertain and needs to be further assessed before biochar can be used on a large scale. In addition, the duration of these GHG reductions is not known and is of pivotal importance for the inclusion of biochar in climate abatement strategies. In a field trial cultivated with Chinese cabbage (Brassica campestris ssp. pekinensis) and radish (Daucus carota L. var. Sativa Hoffm), rapeseed (Brassica campestris L.) and maize (Zea mays L.) straw-derived biochar was added to the soil at rates of 0, 26, 64 and 128 t ha−1, in the whole growing season (October 2011–March 2012) to monitor the effect of treatments on soil GHG production/consumption and soil quality 16 months after biochar addition. The results showed that biochar amendment increased soil pH, nitrate nitrogen content, available phosphorus content and soil water content, but decreased soil bulk density. In biochar-treated plots, soil carbon dioxide (CO2) fluxes were from 20.1 to 87.0% higher than in the control. Soil methane (CH4) uptakes were increased significantly, by 33.2 and 80.1%, between the biochar amendment at the rate of 64 and 128 t ha−1 and the control. Soil nitrous oxide (N2O) fluxes showed no significant difference between biochar amendment and the control. Overall only the CH4 uptake-promoting effect continued into the long term, 16 months after biochar incorporation. This study demonstrates that the beneficial effects of biochar addition might first come through soil quality improvement and carbon sequestration, rather than through effects on the repression of soil C mineralization or the nitrogen cycle.

Impact of biochar field aging on laboratory greenhouse gas production potentials

AbstractRecent observations of decreased greenhouse gas (GHG) production from biochar amended soils have been used to further substantiate the environmental benefit of biochar production and soil incorporation strategies. However, the mechanisms behind this biochar‐mediated response have not been fully elucidated. In addition, the duration of these GHG reductions is not known and is of pivotal importance for the inclusion of biochar into future bioenergy production and climate abatement strategies. In this study, the impacts of biochar field aging on the observed GHG production/consumption were evaluated. Two different wood‐derived biochars and a macadamia nut shell biochar were weathered in an agricultural field in Rosemount, MN (2008–2011) and the impacts on net soil GHG production/consumption were assessed through laboratory incubations. For the three biochars evaluated here, weathering negated the suppression of N2O production that was originally observed from the fresh biochar in laboratory incubations. On the other hand, all three weathered biochars enhanced CO2 production (three‐ to tenfold compared with the fresh biochar amendments) in laboratory soil incubations, suggesting an enhanced microbial mineralization rate of the weathered biochar. This enhanced mineralization could be aided by the chemical oxidation of the biochar surfaces during weathering. Fresh biochar reduced observed soil methane oxidation rates, whereas the weathered biochars had no significant impacts on the observed soil methanotrophic activity. This study demonstrates that for these three biochars, weathering greatly alters the GHG response of the soil systems to biochar amendments.