Fate of iron during hydrothermal liquefaction of hemin

Investigating active phase loss from supported ruthenium catalysts during supercritical water gasification

“…Iron was also shown to remain stable as porphyrin complexes during hydrothermal liquefaction (HTL) of microalgae, 40 with Ru/AC showing the same efficiency as AC in removing Fe from hemin. 41 In long-term continuous SCWG operation, the catalyst will eventually be prone to deactivation too, which can occur in different forms: poisoning (sulphur, transition metals), fouling (coke or salt deposition), sintering, change in the nature of the active phase, "self-gasification of the support, and mechanical or chemical loss of the active phase. 6,[42][43][44] Active Ru/AC catalysts tested in the kinetic regime with model feeds still show deactivation patterns.…”

Incorporating hydrothermal liquefaction into wastewater treatment – Part I: Process optimization for energy recovery and evaluation of product distribution

“…Abundant iron porphyrins (primarily N 4 Fe 1 ) were identified in algal-derived biocrude. Another study also detected many iron porphyrins soluble in hemin-derived biocrude [82]. The iron porphyrins were found to have similar carbon number and double bond equivalent distributions to Ni and V porphyrins that were well-known in petroleum.…”

“…The high contents of Fe, P, and Ca may be related to their initial concentrations that were the highest in the feedstock sludge (0.98, 1.4, and 0.69%, db, respectively). Many studies reported high concentrations of Fe (700-3000 ppm) in HTL biocrude from Fe-rich algae [80,[82][83][84][85], while biocrude from other feedstocks (e.g., lignocellulose) could have lower Fe levels (100-300 ppm) [86,87]. Another study also reported comparable amounts of Zn (88.3 ppm) and Cr (6.6 ppm) in sludgederived biocrude [5].…”