Detailed characterization of waste from date palm (<i>Phoenix dactylifera</i>) branches for energy production: Comparative evaluation of heavy metals concentration

Abstract

Date palm biomass generates a huge amount of waste throughout the world which can be utilized to produce energy through thermochemical or biochemical conversion technologies. The objective of this study is to present a detailed characterization of parts of date palm branches (twig) and analyse the trace elements including heavy metals for environmental safety and potential slagging and fouling in a reactor. The biomass was divided into four parts: L (leaf ribs), SB (small part of the branch attached to the ribs), MB (middle part of the branch), and LB (large part of the branch attached to the trunk). Different characterization techniques applied were X-ray diffraction, Thermogravimetric analysis, FT-IR, Inductively coupled plasma mass spectrometry, X-Ray Fluorescence, Higher heating values, and ultimate (CHNSO) analysis. High crystallinity was observed in LB with all the heavy metals present in permissible limits. However, it showed a considerably high moisture holding capability. Conversely, SB was found to have low moisture holding capability, moderate higher heating values, and one heavy metal (As) higher than the permissible limit defined by the European Union standards. It can be concluded that LB can be used directly for energy generation after sun drying. The other parts are required to be treated for heavy metal reduction before being used for energy production, keeping in mind the environmental safety.