title: Enhancing soluble phosphorus removal within buffer strips using industrial by-products.
abstract: Using industrial by-products (IBPs) in conjunction with buffer strips provides a potentially new strategy for enhancing soluble phosphorus (P) removal from agricultural runoff. Here, we investigate the feasibility of this approach by assessing the P sorption properties of IBPs at different solution-IBPs contact time (1-120 min) and solution pH (3, 5.5, 7.5), as well as possible adverse environmental effects including P desorption or heavy metal mobilisation from IBPs. Batch experiments were carried out on two widely available IBPs in the UK that demonstrated high P sorption capacity but different physicochemical characteristics, specifically ochre and Aluminium (Al) based water treatment residuals (Al-WTR). A series of kinetic sorption-desorption experiments alongside kinetic modelling were used to understand the rate and the mechanisms of P removal across a range of reaction times. The results of the kinetic experiments indicated that P was initially sorbed rapidly to both ochre and Al-WTR, followed by a second phase characterised by a slower sorption rate. The excellent fits of kinetic sorption data to a pseudo-second order model for both materials suggested surface chemisorption as the rate-controlling mechanism. Neither ochre nor Al-WTR released substantial quantities of either P or heavy metals into solution, suggesting that they could be applied to buffer strip soils at recommended rates (≤30 g kg(-1) soil) without adverse environmental impact. Although the rate of P sorption by freshly-generated Al-WTR applied to buffer strips reduced following air-drying, this would not limit its practical application to buffer strips in the field if adequate contact time with runoff was provided.
authors.affiliation: Lancaster Environment Centre, Lancaster University, Lancaster, UK, LA1 4YQ, r.habibiandehkordi@lancaster.ac.uk.
authors.forename: Reza
authors.initials: R
authors.lastname: Habibiandehkordi
authors.forename: John N
authors.initials: JN
authors.lastname: Quinton
authors.forename: Ben W J
authors.initials: BW
authors.lastname: Surridge
mesh_terms: D000327:Adsorption; D000383:Agriculture / Q000379:methods; D000535:Aluminum / Q000737:chemistry*; D000704:Analysis of Variance; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D019216:Metals, Heavy / Q000737:chemistry; D008956:Models, Chemical; D010758:Phosphorus / Q000737:chemistry* / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*; D014881:Water Supply / Q000032:analysis*
chemical_list: D004396:Coloring Agents; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D000535:Aluminum