Review: Progress with Functional Materials Based on Loess Particles

Abstract

Loess is a large-scale deposit which is easy to mine and widely distributed on the epipedon. The clay fraction of loess, also known as 'loessial clay', is a very important component of loess which affects its properties and performance. From a 'materials' perspective, the clay fraction of loess has been ignored. Recently, loess particles have attracted interest because of their potential applications. The focus in the current review is on the methods of modifying loess particles and their application as functional materials. The major components of loess particles are clays, calcite, and quartz, with the clays including kaolinite, illite, montmorillonite, and chlorite. Loess has a range of particle sizes, types, and dispersibilities. The particles agglomerate readily, mainly because cementation occurs readily in the clay fraction. Loess particles can be modified and their properties can be improved by compaction, separation, purification, acidification, calcination, surfactant modification, geopolymerization, and polymer modification. Loess-based functional materials have been used as sorbents, eco-friendly superabsorbents, soil and water conservation materials, humidity-regulating materials, and building materials. Separated and purified loess particles can adsorb metal ions and harmful elements directly. Surfactant-modified loess particles can remove organic compounds effectively. After modification with polymers, loess particles exhibit greater capacity for the removal of environmental pollutants such as harmful metal ions and dyes. As a superabsorbent, modified loess shows excellent thermal stability and swelling behavior. Calcined loess could be utilized as an energy-saving building material with good humidityregulating performance, and geological polymerization has further expanded the scope of applications of loess in architecture. In summary, loess-based functional materials, which are inexpensive and ecologically friendly, deserve more attention and further development. Keywords-Application . Clay . Functionalization . Loess-based materials . Loess particles CLASSIFICATION, DISTRIBUTION, COMPOSITION, AND PHYSICOCHEMICAL PROPERTIES OF LOESS Classification and Distribution Loess can be classified from various perspectives. Using the geological and geographical classification, loess has been divided into plateau, intermontane basin,

A simple and efficient method for loess separation and composition analysis

“…Clay is a very essential aspect of loess, which impacts the homes of loess, such as moist sinkability, swelling and absorption. Loess particles tend to clump together precisely because the clay is prone to cementation (Shen et al, 2021). Its main compositions are silica, aluminosilicate, CaCO 3 , Fe particles, and carbonaceous particles.…”

“…Its major aspects are clay minerals and non-clay minerals with the former which includes illite, kaolinite, montmorillonite, and chlorite whilst the latter containing quartz, feldspar, mica (Fig. S1), and so on (Shen et al, 2021;Grandjean et al, 2019). Aluminosilicate, which consists of a tetrahedron of SiO 4 changed via a tetrahedron of AlO 4 , has been properly used in the synthesis of zeolites (Heard et al, 2019) and geopolymer as binder to encapsulate selective strontium titanate ion exchanger (Ke et al, 2019), aluminosilicate multifunctional microspheres additionally exhibit super overall performance in the elimination of organophosphorus pesticides (Zhang et al, 2018).…”

“…X-ray diffraction (XRD) is the key tool in mineral exploration because each mineral type is de ned by a characteristic crystal structure, which gives a unique X-ray diffraction pattern, allowing rapid identi cation of minerals present within a rock or soil sample (Tan et al, 2020). The main clay mineral compositions in natural loess particles are illite, montmorillonite, chlorite, and kaolinite (Shen et al, 2021;Castellini et al, 2017). Here, XRD pattern (Fig.…”

“…The clay includes kaolinite, illite, montmorillonite and chlorite. (Shen et al, 2021). The non-clay minerals containing quartz, feldspar, mica, and so on.…”

Synthesis of semicoke-based geopolymers as delivery vehicles for slow release of herbicides

“…13,14 However, there are few studies on its application in agricultural production. Furthermore, geopolymers (GPs), amorphous aluminosilicate-based polymers formed by alkaline activation of salic mineral materials, 15 have been receiving extensive attention due to their low cost, eco-friendly nature and excellent performance. The advantages of GPs are excellent mechanical performance, acid and alkali resistance and high temperature resistance.…”