title: Cryogel-supported titanate nanotubes for waste treatment: Impact on methane production and bio-fertilizer quality.
abstract: By reducing the cadmium (Cd(2+)) content in biomass used for bio-based products such as biogas, a less toxic bio-based fertilizer can be obtained. In this work, we demonstrate how a macroporous polymer can support titanate nanotubes, and we take advantage of its known selective adsorption behavior towards Cd(2+) in an adsorption process from real nutrient-rich process water from hydrolysis of seaweed, a pollutant-rich biomass. We show that pretreatment steps involving alteration in area-to-volume ratio performed in aerated and acidic conditions release the most Cd(2+) from the solid material. By integrating an adsorption step between hydrolysis and the biomethane, we show that it was possible to obtain high Cd(2+) removal (ca. 94%) despite molar excess (between 100 and 500) of co-present ions (e.g., Mg(2+), Ca(2+), Na(+), K(+)) and with maintained total phosphorous content. The bio-methane potential did not significantly decrease as compared to a process without cadmium removal and the yielded bio-fertilizer followed Swedish guideline values. This study provides a sound and promising alternative for a novel remediation step, enabling higher use of otherwise tricky and to some extent overlooked biomass sources.
authors.affiliation: Department of Biotechnology, Lund University, P.O. Box 124, Sweden. Electronic address: Linda.Onnby@biotek.lu.se.
authors.forename: Linda
authors.initials: L
authors.lastname: Önnby
authors.affiliation: Department of Biotechnology, Lund University, P.O. Box 124, Sweden.
authors.forename: Kirsebom
authors.initials: K
authors.lastname: Harald
authors.affiliation: Department of Biotechnology, Lund University, P.O. Box 124, Sweden.
authors.forename: Ivo Achu
authors.initials: IA
authors.lastname: Nges
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000302:isolation & purification*; D059985:Cryogels / Q000737:chemistry; D005308:Fertilizers / Q000382:microbiology; D008697:Methane / Q000096:biosynthesis; D043942:Nanotubes / Q000737:chemistry*; D012624:Seaweed / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry; D014875:Water Pollutants, Radioactive / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000295:instrumentation* / Q000379:methods
chemical_list: D002104:Cadmium; D059985:Cryogels; D005308:Fertilizers; D008697:Methane; D014025:Titanium; D062065:Wastewater; D014875:Water Pollutants, Radioactive; C009495:titanium dioxide
keywords: Adsorption; Bio-fertilizer; Bioenergy; Cadmium; Macroalgae; Nanocomposites