Carbon conversion and stabilisation of date palm and high rate algal pond (microalgae) biomass through slow pyrolysis

The processing of waste through pyrolysis technology is gaining momentum worldwide and is considered to be a green technology to reduce CO2 emissions. This study is devoted to analysing the lignocellulosic biomass (date palm) and wastewater-derived microalgae and the carbon-rich char produced between temperature range (400 degrees C-600 degrees C) from these biomass types. The properties of microalgae char showed that significant variation with date palm char exhibited high heating values (24-28 MJ/kg), low ash content (11%-16%), and high energy yield (48%-42%). Algal biomass char showed considerably high nitrogen content (6%-7%) as compared with date palm char (<1%), lower stability, and more significant influence on the price with respect to treatment temperature. Quaternary, pyrrolic, and pyridinic nitrogen species were found on the surface of the microalgae char, whereas no nitrogen species detected on date palm char due to low nitrogen content. The activation energy was also noted to be high for algal char during pyrolysis and combustion process. It can be concluded that date palm char is suitable for energy applications, whereas, algal char can be used for soil amendment, wastewater treatment, and applications requiring nitrogen-doped char.