What is biochar? Bioch
ar is a porous carbon material derived from pyrolyzing biomass. Most any cellulosic biomass can be used such as grasses, hemp, agricultural waste and forest residue. The most common forms for activated carbon include woody biomass, coconut husks, and corn stover.
How is it made? Biochar is made through a process call pyrolysis, which is the thermal degradation of the biomass in the absence of air to form a product high in carbon content. In addition to producing biochar, pyrolysis also produces gases and liquids, which can be processed to form a variety of products such as chemicals and fuels normally produced from petroleum.
Why is it sustainable? 
From the overall lifecycle point of view, the use of biochar is environmentally friendly. The growth of biomass (e.g. crops) is based on photosynthesis, which absorbs energy from sunlight and converts it into chemical energy. A common reaction is CO2 + H2O + photons ® C6H12O6 + 6 O2. The biomass pyrolysis is an exothermic process. The pyrolysis reaction C6H12O6 ® 6 H2O + 6 C is spontaneous provided the water content of the feedstock is not very high. This reaction leads to the formation of biochar and releases water and heat. Biochar is stable for thousands of years. Hence, reduction of CO2 in the atmosphere can be realized through carbon sequestration upon large-scale use of biochar for water treatment.
Why is it important? Plasma activated biochar has a broad variety of applications that benefit the society. Using functionalized biochar to resolve environmental issues, such as PFAS contaminated drinking water, provides a green solution to the urgent environmental problem and improves the ability to protect human health. When we use plasma activated biochar instead of activated carbon made from coal, we reduce greenhouse gases and use less energy. Thus, it is significantly more environmentally friendly than most activated carbons currently used throughout the world.