Soil is the foundation of human existence and development, an important carrier of nutrient circulation, and an important part of the earth ecosystem. China has a vast area of cultivated land, which is one of the largest agricultural countries in the world, but the farmland environment is facing a great threat. Biochar is a kind of material obtained by pyrolysis of raw materials under anoxic or anaerobic conditions, which has good properties and is widely used in soil improvement. In this paper, the modification and preparation methods of biochar were introduced, and the effects of adding biochar on soil infiltration capacity, evaporation capacity, soil nutrients, soil microbial and enzyme activities and the promotion of soil remediation were summarized. It was found that the effect of biochar on soil remediation was mainly related to raw materials, preparation conditions, addition amount and addition methods of biochar. At the same time, the future research direction is prospected, and it is proposed that all kinds of biochars should be reasonably classified, and then the best utilization mode of all kinds of biochars is discussed, which provides theoretical basis and basis for further popularization and utilization of biochars.

The emergence of supramolecular chemistry is a new era of chemical development. It is a rapidly developing new interdisciplinary subject. Many major achievements have been made. Supramolecular chemistry refers to two molecules (host and guest) or multiple molecules. Under the action of the non-covalent bond between molecules, a highly complex multi-molecular polymer with specific functions and special properties is formed. After literature search, the cyclodextrin and its derivatives are briefly introduced based on references, and the pharmaceutical aspects of cyclodextrin and its derivatives are reviewed in terms of sources, preparation methods, properties, and applications.

In this study, biochar produced by anaerobic combustion of wheat straw and corn straw in Henan Province at 300 ℃, 500 ℃ and 700 ℃ was used. The chemical properties of wheat biochar and corn biochar, such as pH and infrared spectra, were studied with the increase of temperature. The chemical properties of wheat and corn biochars were compared based on the related literatures.It was found that the pH of biochar from wheat straw and corn straw combustion increased with the increase of temperature. Through the analysis of infrared spectra, it was found that the pH change of the two biochars may be related to the content of functional groups in the biochars themselves. With the increase of temperature, the spectra showed that the functional groups of the two biochars, such as hydroxyl and carboxyl,The main reason is that the chemical bonds of the above functional groups are broken with the increase of temperature. Resulting in a decrease in the number of acidic functional groups and an increase in the alkalinity of the biochar.

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