Spiral path three phase fluidized bed reactor for treating wastewater contaminated with engine oil

In this study, a new type of circulating three-phase fluidized bed reactor was conducted by adding a spiral path and was named as spiral three-phase fluidized bed reactor (TPFB-S) to investigate the possibility for removing engine oil (virgin and waste form) from synthetic wastewater by using Ricinus communis (RC) leaves natural and activated by KOH. The biosorption process was conducted by changing particle diameter in the range 150–300 and 300–600 µm, liquid flow rate in the range 2.5–4.5 L/min and gas flow rate in range of 0–1 L/min, while other parameters initial oil emulsion concentration, pH, adsorbent concentration, agitation speed and contact time were kept constant at 2000 mg/L, 2,400 mg/L, 200 rpm and 90 min, respectively. Both FTIR and SEM tests showed that the Ricinus communis surface contains of active and strong groups; therefore, it shows a morphological characteristic of interest. The tests of FTIR and SEM explained that the adsorbent solid texture consists of negative valences that related to strong and active groups like carboxyl and hydroxyl groups. Furthermore, the results showed that the removal efficiency reaches about 91 and 98% for both virgin and waste oil at 150–300 µm particle size, 3.5 l/min liquid phase flow rate and 1 L/min air flow rate and for 90 min by using natural and activated form of RC leaves, respectively. In addition, results revealed that 95% of oil was recovered from the adsorbent by using 150mL/L of hexane. Finally the results concluded that TPFB-S has a better performance than the traditional fluidized bed, where the removal efficiency was enhanced by about 23% and 17% for removing virgin oil emulsion from aqueous solution by natural and activated form of adsorbent, respectively.