The spatial configuration of mesovoids profoundly affects the aerobic composting microenvironment, which governs vital processes such as greenhouse gas production and emission, thermal conduction, and overall composting efficiency. Nondestructive in-situ characterization of the composting spatial structure is crucial to better understand its interaction mechanism with the microenvironment. In this study, a valuable contribution to the field of composting research was made by introducing micro-computed tomography (micro-CT) tool for in situ three-dimensional (3D) visual characterizing the void structure dynamics of straw and manure compost pile units at the mesoscale.
View Article and Find Full Text PDFBiochar, a cost-effective adsorbent for the removal of heavy metals from aqueous solutions, has gained increasing attention. In this study, an advanced micro-computed tomography (micro-CT) system was used to investigate the adsorption kinetics by direct localization and visualization of Pb (II) on wheat straw pellet biochar. The normalized digital images indicating the dynamic changes of Pb (II) adsorption on biochar samples at different initial Pb (II) concentrations of 100, 200, 300, and 400 mg/L and adsorption times were obtained.
View Article and Find Full Text PDFThe micro-CT technique was applied in adsorption visualization of Pb (II) on the pellet biochar derived from wheat straw to provide information on understanding the complex heavy metal-biochar interaction during the process. The 3D distribution of Pb (II) on the biochar was well in line with the results of isothermal and kinetic adsorption experiments as well as those of simulation with Langmuir and Weber-Morris intraparticle diffusion (IPD) models. It was shown that Pb (II) was preferentially adsorbed on the surface of the biochar at an initial Pb (II) concentration of 50 mg/L.
View Article and Find Full Text PDFIt is crucial to develop a new characterization method to provide insight into the complex adsorption mechanism of crop residue-derived char. This study established a novel 3D in-situ visualization method for qualitative and semi-quantitative characterizing Pb (II) adsorption profiles in crop residue-derived char particles. First, coconut shell activated carbon, rice husk biochar, and wheat biochar after Pb (II) adsorption was used for X-ray micro-CT imaging.
View Article and Find Full Text PDFTo further explain effects of pyrolysis temperature on physicochemical properties of corn stalk pellet biochar from a new perspective, various lab physicochemical analysis methods combining microcomputed tomography were used to characterize biochar in this study. The results showed that at pyrolysis temperatures from 300 °C to 800 °C, yield of biochar decreased logarithmically with increasing pyrolysis temperature (T); changes of proximate and elemental compositions all showed significant differences, but the change rules were not consistent; high temperature pyrolysis biochar had high stability, high hardness and was convenient for storage and transportation; the proportions of hydroxyl group and amino group were highest in BC800 and BC600, respectively, contributing to the adsorption and removal of pollutants; BC400 had the best combustion performance; X-ray mean attenuation coefficient (XMAC) showed the following correlations, namely, XMAC = 0.003*ln(T-285.
View Article and Find Full Text PDFIn order to explore the effects of different mechanical fragmentation on cellulose separation and cellulose polymorphic transformation of wheat straw during alkali treatment, one coarse milled (CM) and two ball milled wheat straw samples (BM30 and BM120) were treated with different NaOH concentrations (1%-10%), and the lignocellulosic compositions and crystalline-structural various were quantitative and qualitative characterized. The quantitative equations between cellulose content and NaOH concentration of different mechanical treated samples were Y = 69.8-35.
View Article and Find Full Text PDFWeed control is a substantial challenge in field management. A better weed control method at an earlier growth stage is important for increasing yields. As a promising weed control technique, intelligent weeding based on machine vision can avoid the harm of chemical weeding.
View Article and Find Full Text PDF