Novel and green processes for citrus peel extract: a natural solvent to source of carbon

Annual worldwide production of citrus fruits is estimated to be more than 120 MT, out of which nearly 50% is waste in terms of citrus peel. Although orange peel waste is further processed to yield valuable chemicals such as limonene and pectin, the processes involved are highly energy consuming and uneconomical and, therefore, have limited industrial acceptability. Here, we present cost-effective, low-energy, novel and green approaches to directly use the extract of citrus fruit’s peel as print transfer medium, solvent for recycling polystyrene waste and natural polymers. Furthermore, the fine solid suspended particles in the middle layer of the extract also find their use as a source of glassy carbon upon pyrolysis. This work may be an exemplary way of green engineering to use the waste as resource for environmental sustainability.