Characteristics of biochar from algae of the sea of Japan

Abstract

The paper presents a comparative analysis of biochars produced from seaweed collected from the Sea of Japan, including Ahnfeltia tobuchiensis, a mixture of algae (Neorhodomela sp.), Zostera marina, Phyllospadix iwatensis, and Saccharina japonica, and Zostera marina. Medium-temperature pyrolysis (500 °C) was used to produce the biochars, with a carbonation time of 1 hour. These biochars have an alkaline reaction and can be used as soil ameliorants for acid soils. The yield of biochar produced after medium-temperature pyrolysis ranges from 39% to 57%, with the highest yield coming from Ahnfeltia tobuchiensis and the lowest from Saccharina japonica. All of the biochars contain essential nutrients, including nitrogen (N), phosphorus (P), and potassium (K). Biochar obtained from the algal mixture appears to be the most promising raw material for producing biochar due to its high content of these elements and good yield. In general, all biochar derived from marine macroalgae can be considered a promising organic fertilizer. Not only the extracted algae, but also the storm emissions from them, can be used as raw materials. This makes the production of biochar from these sources a potentially promising product for the fertilizer market.