Intrinsic activation: the relationship between biomass inorganic content and porosity formation during pyrolysis

Combined Plant Growth-Promoting Bacteria Inoculants Were More Beneficial than Single Agents for Plant Growth and Cd Phytoextraction of Brassica juncea L. during Field Application

Single or combined plant growth-promoting bacteria (PGPB) strains were widely applied as microbial agents in cadmium (Cd) phytoextraction since they could promote plant growth and facilitate Cd uptake. However, the distinct functional effects between single and combined inoculants have not yet been elucidated. In this study, a field experiment was conducted with single, double and triple inoculants to clarify their divergent impacts on plant growth, Cd uptake and accumulation at different growth stages of Brassica juncea L. by three different PGPB strains (Cupriavidus SaCR1, Burkholdria SaMR10 and Sphingomonas SaMR12). The results show that SaCR1 + SaMR10 + SaMR12 combined inoculants were more effective for growth promotion at the bud stage, flowering stage, and mature stage. Single/combined PGPB agents of SaMR12 and SaMR10 were more efficient for Cd uptake promotion. In addition, SaMR10 + SaMR12 combined the inoculants greatly facilitated Cd uptake and accumulation in shoots, and enhanced the straw Cd extraction rates by 156%. Therefore, it is concluded that the application of PGPB inoculants elevated Cd phytoextraction efficiency, and the combined inoculants were more conductive than single inoculants. These results enriched the existing understanding of PGPB agents and provided technical support for the further exploration of PGPB interacting mechanisms strains on plant growth and Cd phytoextraction, which helped establish an efficient plant–microbe combined phytoremediation system and augment the phytoextraction efficiency in Cd-contaminated farmlands.

Torrefaction of Agricultural and Wood Waste: Comparative Analysis of Selected Fuel Characteristics

Abundant biomass is a potential energy source. However, it possesses several challenges when considered for energy applications. Torrefaction, a thermal pretreatment process can improve the properties of biomass as energy source. This study focused on comparing effect of torrefaction operating parameters on agricultural and wood wastes properties as fuel. The physiochemical properties, composition, moisture-biomass interaction and ash melting behavior were determined. The result show that higher torrefaction temperature and longer residence time increased lignin content, reduced hemicellulose and cellulose content. The moisture uptake of torrefied biomass was reduced in the range 2.47–9.94% compared with raw biomass depending on torrefaction temperature that indicate torrefied biomass was more hydrophobic than raw biomass. The moisture adsorption isotherm curve shows type II isotherm based on the Brunauer-Emmett-Teller’s (BET) classification and was best described by the Oswin model. In addition, torrefaction treatment showed significant influence on the melting behavior of the biomass ash. Especially for agricultural wastes, the fouling tendency shifted from serious range to low range with torrefaction treatment. Torrefaction showed promise for improving fuel characteristics of the studied biomass.

Characterization of corncob-derived biochar and pyrolysis kinetics in comparison with corn stalk and sawdust

In this study, thermal and physicochemical characterization results of corncob (CC) and its derived biochars were analyzed and differentiated from sawdust (SD) and cornstalk (CS). The pyrolysis temperature shows the largest effect on the yield of biochar produced compare with residing time, heating rate, and feedstock particle size. The CC-derived biochars produced at temperatures ranging from 300 to 600°C were analyzed. The CC was thermochemically altered to a stable biochar when the pyrolysis temperature was set to over 500°C. To deduce the reaction mechanism of the CC during the major thermal decomposition stage, 16 mechanisms in solid-state reactions were applied. The reaction order and nucleation mechanisms described the thermal decomposition of the CC. By using the best-fitted mechanisms, the kinetic parameters were calculated. The weight active energy of the CC was 122.42kJ/mol, which was the lowest value compared to those of CS and SD.