Co-biosorption of Copper and Glyphosate by Ulva lactuca

MARÍA A. TRINELLI; MARÍA MAR ARECO; MARIA DOS SANTOS AFONSO

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 105 p. 251 - 258

0927-7765

This study investigated the adsorption of glyphosate (PMG) onto the green algae Ulva lactuca mediated by Cu(II). Results demonstrated that U. lactuca adsorbs PMG when the process is mediated by Cu(II) with molar ratios Cu(II):PMG ≥ 1.5:1. U. lactuca was characterized by water adsorption surface area, FTIR, SEM and EDS. The Langmuir and Freundlich models were applied. Results showed that the biosorption process for copper and PMG in the presence of copper were described by the Langmuir model (qmax=0.85±0.09 mmol g-1, KL=0.55±0.14 l mmol-1 and qmax=3.65±0.46 mmol g-1, KL=0.103±0.03 l mmol-1, respectively). Copper adsorption was greater in the presence of PMG than in the absence of the pesticide and the adsorption can only be represented by the Freundlich model (KF= 0.08±0.01, 1/n= 1.86±0.07). In all cases studied, the maximum metal uptake (qmax) increased with increasing pH. Surface complexes with a stoichiometry ranging from ≡Cu-PMG-Cu to ≡Cu-PMG-Cu3 are suggested as reaction products of the process. Due to the increasing amounts of PMG applied in Argentina, natural reservoirs present considerable amounts of this herbicide. The value of this work resides in using U. lactuca, a marine seaweed commonly found along coastlines all over the world, as a biosorbent for PMG.