Removal of Heavy Metals from Aqueous Solutions with the Use of Lignins and Biomass

The overproduction of pollutants resulting from the development of industry causes the deposition of large amounts of toxic and carcinogenic substances, including heavy metals, in the aquatic ecosystem and other ecosystems. This is a civilisation problem of the present times, posing a serious threat to the natural environment, including humans. For this reason, it has recently become extremely important to develop effective methods to minimise the concentration of heavy metal ions in the aquatic systems and thus reduce their negative impact on the environment. One such technique is adsorption, which is believed to be an effective method of removing contaminants such as heavy metal ions from aqueous solutions. Looking at the available literature of the last few years, it can be concluded that adsorbents of natural origin are becoming more and more important. These are agricultural waste, all kinds of biomass, and waste from various industries. The study attempts to present and evaluate the sorption capacity of materials of natural origin, including oat bran, chitosan, alginate, tree bark, coconut fibre, and lignin. The use of such biosorbents is more friendly for the environment compared to their synthetic counterparts and perfectly fits the concept of sustainable development and the circular economy.