Iron oxide in particulate, pellet, and granule form; iron oxide as a dispersion; iron oxide as a sorbent; iron oxide for use in technical applications, namely, air purification, environmental remediation, and water purification; iron oxide for use as an abrasive; iron oxide for use as a catalyst; iron oxide for use as a synergist; iron oxide for use as an additive; iron oxide for use as a pigment; iron oxide