title: Fast and slow rates of naphthalene sorption to biochars produced at different temperatures.
abstract: This study investigated the sorption kinetics of a model solute (naphthalene) with a series of biochars prepared from a pine wood at 150-700 °C (referred as PW100-PW700) to probe the effect of the degree of carbonization of a biochar. The samples were characterized by the elemental compositions, thermal gravimetric analyses, Fourier transform IR spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller-N(2) surface areas (SA), and pore size distributions. Naphthalene exhibited a fast rate of sorption to PW150 owning a high oxygen content and a small SA, due supposedly to the solute partition into a swollen well-hydrated uncarbonized organic matter of PW150. The partial removal of polar-group contents in PW250/PW350, which increased the compactness of the partition medium, decreased the diffusion of the solute into the partition phase to result in a slow sorption rate. With PW500 and PW700 displaying low oxygen contents and high SA, the solute sorption rates were fast, attributed to the near exhaustion of a partition phase in the sample and to the fast solute adsorption on the carbonized biochar component. The results illustrate that the sorption rate of a solute with biochars is controlled largely by the solute's diffusivity in the biochar's partition phase, in which the medium compactness affects directly the solute diffusivity.
authors.affiliation: Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Zaiming
authors.initials: Z
authors.lastname: Chen
authors.forename: Baoliang
authors.initials: B
authors.lastname: Chen
authors.forename: Cary T
authors.initials: CT
authors.lastname: Chiou
mesh_terms: D000327:Adsorption; D002606:Charcoal / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D017745:Incineration; D007700:Kinetics; D008956:Models, Chemical; D009281:Naphthalenes / Q000032:analysis / Q000737:chemistry*; D028223:Pinus; D012989:Soil Pollutants / Q000737:chemistry*; D013696:Temperature; D014934:Wood
chemical_list: D009281:Naphthalenes; D012989:Soil Pollutants; C540010:biochar; D002606:Charcoal; C031721:naphthalene