Biomass: from Waste to Valuable Materials

Biomass originating from agricultural waste if improperly disposed of will cause emissions of N₂O, SO₂, CH₄ and large amounts of smoke into the atmosphere, causing global pollution problems[.1] . Agricultural waste is organic matter disposed of by humans in the process of agriculture and includes waste from crops, chemicals and[.2]  rural households.[.3]  Apart from environmental pollution, economic losses caused by traditional disposal of agricultural waste cannot be ignored. Burning agricultural waste, including crop residues, in the open air or the kitchen is one of the main sources of serious air pollution.[.4]  On the other hand, agricultural waste can be utilized as valuable materials, such as bio-adsorbents, because it has loose and porous structural properties as well as functional groups like carboxyl and hydroxyl. In addition, agricultural waste is [.5] available in large quantities, can be recycled, is biodegradable, and is environmentally friendly so that it has good prospects for the comprehensive utilization of resources when used to control environmental pollution.

This special edition contains 20 papers, 9 of which discuss the use of biomass as bio-adsorbents. In addition, there is 1 paper that discusses the production of low-fat ice cream, 2 papers from electrical engineering, 5 papers from mechanical engineering, 1 paper from metallurgical engineering and 2 papers from environmental engineering.

The first paper, written by M. Cornelia and Sanny, proposed to make low-fat pumpkin and date palm ice cream as a source of antioxidants and dietary fiber using different types of stabilizers. Several formulations of ice cream were examined. The best formulation was made with gelatin stabilizer with the addition of pumpkin puree and date palm puree at the ratio of 1:2 and can be categorized as high-fiber ice cream as it contains no less than 6 g of dietary fiber in 100 g formulation.

The second paper, written by A. H. P. Harahap, A. A. Rahman, I. N. Sadrina and M. Gozan, investigated the effect of microwave-assisted alkaline pretreatment of OPEFB by using response surface methodology with Box–Behnken design[.6]  (BBD) to find the optimum pretreatment conditions. The authors reported that, to achieve the highest lignin removal of 88.10%, the optimal conditions for the pretreatment were a combination of microwave power at 832.9 W, a NaOH concentration at 2.7% (w/v), and a reaction time of 8.9 min.