Rare earth elements, due to their unique chemical properties and rich electronic structure, are widely used in the field of environmental purification. These elements include lanthanides and scandium, yttrium, etc., which exhibit excellent performance in catalysis, adsorption, photocatalysis, etc. This article will discuss the application of rare earth elements in environmental purification and how they can improve environmental quality through chemical processes.
First of all, the application of rare earth elements in catalytic purification is particularly prominent. For example, rare earth catalysts play an important role in the purification of automotive exhaust gases. In three-way catalytic converters, rare earth elements such as cerium (CE) and lanthanum (LA) can improve the activity and stability of the catalyst and promote the conversion of harmful gases such as carbon monoxide (CO), hydrocarbons (CHX) and nitrogen oxides (NOx). The chemical equation for catalyzing the reaction is as follows:
2co + 2nox → 2co2 + n22chx + 3-x)o2 → 2xco2 + x/2)h2o
In this process, the presence of rare earth elements increases the selectivity and efficiency of the catalyst for these reactions, thereby reducing the emission of harmful gases.
Rare earth elements are also used in water purification. For example, rare earth oxides such as lanthanum oxide (La2O3) and cerium oxide (CEO2) can be used as adsorbents to remove heavy metal ions from water. These oxides adsorb harmful heavy metal ions such as lead (Pb2+) and cadmium (CD2+) to their surface through ion exchange. The adsorption process can be expressed by the following chemical equation:
LA2O3(S) +PB2+(AQ) LABo3(S) +2LA3+(AQ) Chemical Formula Literature **http:360cn/post/555.html
In this reaction, lanthanum oxide is ion-exchanged with lead ions in the water to form stable lead-lanthanum ore, which purifies the water.
In the field of photocatalysis, rare earth elements also play an important role. For example, rare-earth-doped titanium dioxide (TiO2) nanomaterials exhibit excellent performance in photocatalytic splitting of water and organic pollutants. In photocatalytic water splitting reactions, rare earth elements can improve the separation efficiency of photogenerated electrons and holes, and promote the decomposition of water
2H2O + Light Energy 2H2(g) +O2(g).
In this process, the doping of rare earth elements changed the band structure of TiO2 and improved its absorption capacity of visible light, thereby enhancing the photocatalytic efficiency.
In addition, REEs have been used in the preparation of novel adsorbent materials, such as RE-MOFs and RE-MOFs. These materials have a high specific surface area and adjustable pore size, which effectively adsorbs and removes harmful gases from the air, such as volatile organic compounds (VOCs) and sulfur dioxide (SO2). The adsorption process can be expressed by the following chemical equation:
re-mofs + vocs re-mofs-vocs This paper chemical formula literature **http:360cn/post/554.html
In this reaction, the rare-earth-organic framework material captures harmful gas molecules in the air by physical or chemical adsorption.
In short, the application of rare earth elements in environmental purification has broad prospects. They not only improve catalytic efficiency, but also act as highly efficient adsorbents and photocatalysts. With the continuous progress of materials science and environmental engineering technology, the application of rare earth elements in environmental purification will be more diverse and efficient. Through reasonable design and application, rare earth elements are expected to become key materials to solve the problem of environmental pollution, and make greater contributions to the realization of sustainable development and environmental protection.