As(III) and As(V) sorption on iron-modified non-pyrolyzed and pyrolyzed biomass from Petroselinum crispum (parsley)

The sorption of As(III) and As(V) from aqueous solutions onto iron-modified Petroselinum crispum (PCFe) and iron-modified carbonaceous material from the pyrolysis of P. crispum (PCTTFe) was investigated. The modified sorbents were characterized with scanning electron microscopy. The sorbent elemental composition was determined with energy-dispersive X-ray spectroscopy (EDS). The principal functional groups from the sorbents were determined with FT-IR. The specific surfaces and points of zero charge (pzc) of the materials were also determined. As(III) and As(V) sorption onto the modified sorbents were performed in a batch system. After the sorption process, the As content in the liquid and solid phases was determined with atomic absorption and neutron activation analyses, respectively. After the arsenic sorption processes, the desorption of Fe from PCFe and PCTTFe was verified with atomic absorption spectrometry. The morphology of PC changed after iron modification. The specific area and pzc differed significantly between the iron-modified non-pyrolyzed and pyrolyzed P. crispum. The kinetics of the arsenite and arsenate sorption processes were described with a pseudo-second-order model. The Langmuir–Freundlich model provided the isotherms with the best fit. Less than 0.02% of the Fe was desorbed from the PCFe and PCTTFe after the As(III) and As(V) sorption processes.

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► The textural characteristics of PCFe and PCTTFe influence As sorption.
► The pHpzc of PCTTFe is greater than that of PCFe and affects the sorption of As.
► The kinetic parameter (k2) varies according to the chemical species of As.
► The As adsorption capacity (Qo) of PCTTFe is greater than that of PCFe.
► Fe desorption less than 0.02% from PCFe and PCTTFe was observed.