IIT Mandi team uses orange peel hydrochar for biofuel precursors

Researchers from the Indian Institute of Technology Mandi have used hydrochar derived from orange peels to speed up the conversion of biomass-derived chemicals into biofuel precursors, which will likely help overcome the "socio-political instabilities associated with dwindling petroleum reserves".

The development of such catalysts for biomass conversion bodes well for the biofuel sector in the country. Already a pioneer in biomass-based power, in 2015, India had announced its goal to achieve 15 GW of power from biomass, small hydropower and waste-to-energy plants.

Within five years, the country has already achieved the 10 GW target of biomass power.

The findings of the research team have been recently published in the journal ‘Green Chemistry’. The research was led by Dr Venkata Krishnan, Associate Professor, School of Basic Sciences, IIT Mandi, and co-authored by his students Tripti Chhabra and Prachi Dwivedi, according to a press statement.

Biomass-derived products from naturally occurring materials – is currently the fourth most significant energy source that can meet the energy demand after coal, oil, and natural gas, in the country. Lignocellulosic biomass obtained from forestry and agricultural waste, for example, can potentially be converted to a variety of useful chemicals by various methods.

Of these methods, the use of catalysts for the conversion is particularly useful because such processes can be carried out with minimal energy input and the type of product obtained from the biomass can be controlled through the right choice of catalysts and reaction conditions.

Talking about the research, Dr Krishnan, said, “One of the driving interests among the renewable energy community is the development of relatively clean and energy-efficient processes to convert biomass into useful chemicals, including fuel.”

The simplest and most low-cost catalyst that has been studied by researchers for biomass conversion reactions is hydrochar. It is typically obtained by heating the biomass waste (orange peels in this case) in the presence of water through the hydrothermal carbonisation process. The use of hydrochar as a catalyst for biomass conversion is attractive because it is renewable and its chemical and physical structure can be altered for better catalytic efficiencies.

The researchers have used hydrochar derived from orange peels to catalyse the conversion of biomass-derived chemicals into biofuel precursors. The researchers heated dried orange peel powder with citric acid under pressure in a hydrothermal reactor (a lab-level “pressure cooker”) for many hours. The hydrochar that was produced was then treated with other chemicals to introduce acidic sulfonic, phosphate and nitrate functional groups to it.