title: Sorption of cadmium in columns of sand-supported hydrothermally carbonized particles.
abstract: Sanitation in urban slums, especially in countries in Sub-Saharan Africa, is a challenge. One of the solutions to sanitation is to valorize waste, and to convert bio-waste present in the slum in a cheap and affordable way into lignite via hydrothermal carbonization (HTC). HTC is simple, cheap, converts all carbon (100%), eliminates pathogens completely, and requires wet starting products/biomass, thereby avoiding complicated drying schemes. In this research, we investigated the effectiveness of removing a divalent metal-ion, cadmium, using equilibrium batch experiments and columns of sand-supported hydrothermally carbonized colloidal lignite (HTCCL) derived from sugar, maize, and grass. Our results indicated that equilibrium sorption could be best described by a Langmuir isotherm. The uptake capacity varied from 0.11 to 0.21 mg Cd/g HTC, dependent on the type of HTC used. These values were relatively low compared to other carbonaceous sorbents. However, removal efficiencies in column experiments were remarkably high: 70-100% during 20-24 pore volumes or bed volumes of flushing. We concluded that HTCCL is a promising sorbent that can be used to treat heavily polluted water and/or wastewater.
authors: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands E-mail: j.foppen@unesco-ihe.org.
authors: J M V
authors: JM
authors: Minani
authors: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands E-mail: j.foppen@unesco-ihe.org.
authors: J W
authors: JW
authors: Foppen
authors: UNESCO-IHE, Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands E-mail: j.foppen@unesco-ihe.org.
authors: P N L
authors: PN
authors: Lens
mesh_terms: D000327:Adsorption; D000349:Africa; D002244:Carbon; D012822:Silicon Dioxide; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D002244:Carbon; D012822:Silicon Dioxide; D062065:Wastewater; D014874:Water Pollutants, Chemical