Cationized milled pine bark as an adsorbent for orthophosphate anions

Abstract

More efficient adsorption media are needed for removing dissolved phosphorus in surface water runoff. We studied the use of cationized pine bark as a sorbent for dissolved phosphorus in water. Cationized pine bark was prepared by treating extracted milled pine bark with polyallylamine hydrochloride (PAA HCl) and epichlorohydrin (ECH) in aqueous medium. Attachment of PAA HCl to the bark was monitored by percentage of weight gain and nitrogen content. Changes in bark surface chemistry were characterized by zeta potential and inverse gas chromatography measurements. Energy dispersive x-ray analysis and scanning electron microscopy were used to determine changes in chemical composition and morphology of the cationized bark. The cationized bark showed a decrease in the dispersive component of the surface energy and a barely measurable change in the surface acid-base properties. In the pH range 2.5 to 7.9, the cationized bark showed a positive zeta potential, which changed to negative at pH 7.9 or higher. By comparison, the zeta potential of control extracted bark remained negative throughout the pH range of 2.5 to 9. We propose that the reaction of bark with PAA HCl results in a surface network of fixed cationic sites of quaternary ammonium that have mobile chloride ions as counter anions. Preliminary results from batch adsorption experiments indicate that cationized milled bark has an estimated maximum adsorption capacity of approximately 12.65 mg phosphate/g, which compares favorably with that of other well-known phosphorus sorbents.

Adsorption and Removal Kinetics of Phosphonate from Water Using Natural Adsorbents

“…Different types of clays, such as hydroxyapatite, fluorspar, quartz activated with ferric ions, calcite, and quartz, are useful for the removal of fluoride (Chidambaram et al, 2003;Fan et al, 2003). Tshabalala et al (2004) reported cationized pine bark to be a good remover of orthophosphate from water.…”

Leaching of contaminants from untreated pine bark in a batch study: Chemical analysis and ecotoxicological evaluation

“…Pine bark has a complex chemical structure consisting of both extractable and non-extractable components, of which the nonextractable can adsorb cationic polyelectrolytes [8]. Metals are thought to sorb to pine bark by ion exchange at a multitude of ionic sites, both cationic and anionic, with metal ions replacing adjacent hydroxyl groups to form a chelate [23][24][25].…”

“…Pine bark, a by-product from the forest industry, is particularly effective in removing metals from solution [3][4][5][6], storm water run off [7] and landfill leachate [1]. In addition to retaining metals, pine bark has also been shown to efficiently remove phosphorous [8], lindane [9], pentachlorphenol [10,11] and uranium [12] from water. However, one important problem with using pine bark as a filter is the release, or desorption, of contaminants from the unused filter material, particularly during the initial filtration phase.…”

Agricultural By-Products for Phosphorous Removal and Recovery from Water and Wastewater: A Green Technology

“…Based on the effect of pH and desorption results, Anirudhan et al (2006) and Namasivayan and Sangeetha (2004) concluded that ion exchange and chemisorption mechanisms could be important pathways for the removal of P by quaternized banana stem and ZnCl2 activated carbon, respectively. Tshabalala et al (2004) ions onto cationized milled wood residues. From P surface loading and spectroscopic analysis results, Shin et al (2005) claimed that ion exchange and surface precipitation could contribute to the elimination of P by La(III) treated juniper bark fiber.…”