Arsenic adsorption on lignocellulosic substrate loaded with ferric ion

Abstract

We loaded a lignocellulosic substrate extracted from wheat bran with ferric ions. This new lowcost adsorbent was prepared for the adsorption and removal of arsenate and arsenite ions from aqueous systems. The loading process of Fe in this biomaterial was done by hydrolization of a ferric salt while an alkaline solution was added dropwise. The new material obtained has a high sensivity to arsenite and arsenate species. Here, we investigated the effect of contact time, pH, and Fe content on the adsorption of both arsenic ions on the new material. This adsorption was found to be highly pH-dependent, which can be explained on the basis of electrostatic interactions between ionic species in solution and the "FeOH surface groups. The maximum adsorption capacity of arsenite and arsenate species vary linearly with the amount of Fe loaded on the lignocellulosic substrate.

Sorption of V and VI group metalloids (As, Sb, Te) on modified peat sorbents

“…Disodium hydrogen arsenate heptahydrate (Na 2 HAsO 4 × 7H 2 O; Sigma-Aldrich), sodium arsenite (AsNaO 2 ; Fluka), cacodylic acid (C 2 H 7 AsO 2 ; Sigma-Aldrich), potassium hexahydroxoantimonate(V) (KSb(OH) 6 ; Fluka), potassium antimony tartrate semi hydrate (C 4 H 4 KO 7 Sb × 0.5H 2 O; Sigma-Aldrich), potassium tellurite hydrate (K 2 TeO 3 × H 2 O; Sigma-Aldrich) and telluric acid (H 6 TeO 6 ; Sigma-Aldrich) were chemicals of analytical grade. Sorption experiments were provided using three different peat samples modified with Fe(III) hydroxide (Fe-modified peat from the Gagu Bog, Fe-modified peat from the Silu Bog, Fe-modified peat from the Dizais Veikenieks Bog).…”

“…Modification of materials involved precipitation of iron hydroxides on the surface of the studied material with the following thermal treatment [6,8]. 67.55 g (0.25 mol) FeCl 3 × 6H 2 O were dissolved in 250 mL distilled water, adding 250 mL 3M NaOH and leaving for 4 hours.…”

“…The concentration of arsenic in these areas exceeds maximal permissible levels several times [4,[6][7][8]. Arsenic can enter into natural water systems through a range of natural as well as anthropogenic sources.…”

“…Aqueous Te species mainly exist in the form of oxyanions -tellurite (TeO 3 2− ) and tellurate (TeO 4 2− ) or hydroxide anions (Te(OH) 6 , TeO(OH) 3 − ). Te(VI) is the predominant form in aqueous media under oxic conditions, whereas Te(IV) predominates under reducing conditions [14,15].…”

“…However, the main disadvantage is the high costs. It is considered that sorption is one of the most effective and affordable methods [6][7][8]10].…”