Issues of the history of general and applied radiochemistry are presented; shows the role of Russian scientists in the development of the phenomenon of radioactivity, and then scientific research on radiochemistry. Co-precipitation of radionuclides with salts, adsorption of radionuclides by sorbents of various nature, extraction of radionuclides from solutions are considered. Particular attention is paid to the forms of radionuclides in solutions. Applied aspects of radiochemistry are covered - issues of decontamination and processing of liquid radioactive waste formed mainly during the operation of nuclear power plants.