Abstract: Provided is a method for lowering a temperature in thermal remediation of contaminated soil, which belongs to the field of soil and groundwater contamination control technologies. In the present disclosure, the method includes the following steps: injecting an entrainer into petroleum hydrocarbons (PHCs) contaminated soil to be remediated to allow soil remediation by thermal desorption; where the entrainer includes ethanol at a volume percentage of 10% to 50%.

Abstract: The present disclosure provides a machine learning-based hyperspectral detection and visualization method of a nitrogen content in a soil profile. The method includes the following steps: collecting a plurality of soil profile samples; obtaining hyperspectral image data of a soil profile; selecting a plurality of rectangular ranges on a hyperspectral image as region of interest (ROIs), calculating an average spectral curve of all pixels in the ROIs, and analyzing and measuring standard contents of nitrogen in the soil samples corresponding to the ROIs; constructing hyperspectral prediction models of five types of soil nitrogen in the soil profile with reference to different learning algorithms respectively with an average spectrum of ROIs after preprocessing as a predictive variable and a standard soil nitrogen content as a response variable; selecting an optimal prediction model based on evaluation indexes to predict and visualize contents of different forms of nitrogen in the entire soil profile.

Abstract: Provided are a mercapto group-loaded layered double hydroxide (LDH)-based magnetic composite particle, and a preparation method and use thereof. The method includes: dissolving a water-soluble divalent magnesium salt and a water-soluble trivalent aluminum salt in water to obtain a mixed salt solution; pumping ammonia water into the mixed salt solution, and performing reaction I under stirring, subjecting an obtained product to centrifugation, and washing product obtained with deionized water; mixing the product with water, ethanol, and a coupling agent KH-580 to obtain a mixture, subjecting the mixture to reaction II while stirring to obtain mercapto group-loaded LDH; mixing the mercapto group-loaded LDH with ferroferric oxide and sodium alginate, adding deionized water thereto, and stirring to obtain a homogeneous mixed solution; adding the homogeneous mixed solution into a calcium chloride solution dropwise to form a magnetic bead; and leaving the magnetic bead to harden, and then washing and drying.