As(V) retention on soils and forest by-products and other waste materials

Abstract

As(V) retention capacity is determined by means of adsorption/desorption trials performed for coarse and fine ground mussel shell, forest and vineyard soils with or without fine shell, pine wood ash, oak wood ash, pine sawdust and slate-processing fines. Pine ash shows the highest arsenic retention potential (with >97 % adsorption and ≤1 % desorption), followed by shell-amended forest soil (adsorption between 96 and 92 %), by un-amended forest soil (adsorption between 98 and 86 %) and by the amended vineyard soil (adsorption between 92 and 75 %). Sawdust is the material with the lowest arsenic retention capacity in most cases, with un-amended vineyard soil also showing poor results. In the case of oak ash, As(V) percentage adsorption becomes higher with increasing added arsenic concentrations, while this increase in added arsenic causes lower percentage adsorption in the case of slate fines. Regarding adsorption ability, As(V) adsorption data were fitted to Freundlich and Langmuir models, showing good fitting, with pine ash and shell-amended forest soil having the highest K F values. In view of that, mussel shell amendment would be useful to increase arsenic retention on forest and vineyard soils, while pine ash could be used to retain arsenic even from wastewaters.

Wheat Straw as a Bio-Sorbent for Arsenate, Chromate, Fluoride, and Nickel

“…For As(V) and Cr(VI), an increase in the pH of the equilibrium solution took place as the added concentration of these elements increased. The same was observed by Fernández-Pazos et al [25] studying chromium sorption and by Seco-Reigosa et al [11] studying arsenic sorption. This behavior may occur when the samples adsorb Cr(VI) and As(V) predominantly by electrostatic attraction between the adsorbent surface and the anionic species of these elements, releasing OH − and causing an increase in pH [10,34,35].…”

“…Ni 2+ showed notable sorption and an opposite trend to that of F − , with sorption percentage increasing when the highest Ni 2+ concentrations (3 and 6 mmol·L −1 ) were added. We have previously studied [10][11][12][13][25][26][27][28]] the effects of different concentrations, pH, incubation time, and other variables on As(V), Cr(VI), F − , and/or Ni 2+ retention on other sorbent materials, but it should be also performed for wheat straw in future works.…”

“…To fight heavy metal, metalloid, and F − pollution, different waste and by-products have been studied as bio-sorbents [8,9], including mussel shell [10][11][12] and wood industry waste [13]. As indicated by Malik et al [14], some cellulosic materials (as wheat straw) can be effective low-cost sorbents.…”

Cadmium and Lead Sorption/Desorption on Non-Amended and By-Product-Amended Soil Samples and Pyritic Material

“…The higher Pb sorption on the forest soil compared to the pyritic material could be attributed to the higher organic matter content of the former. It could also explain the higher Cd sorption on the forest soil with respect to the vineyard soil, in conjunction with the Alo and Feo contents in the forest soil sample (See Supplementary Material), as previously pointed out by Fernández-Pazos et al [22] and Seco-Reigosa et al [26].…”

“…In fact, Fu and Wang [1] reviewed the sorption capacities of agricultural and industrial waste and by-products, as well as of various types of natural substances, finding promising results. In this regard, in the last years we have studied several sorbents for the removal or retention of cationic heavy metals (Cd, Cu, Hg, Ni, Pb, Zn) [16][17][18][19][20], and anionic pollutants (Cr(VI) and As(V)) [21][22][23][24][25][26][27][28]. However, as far as we know, no previous study has dealt with Cd and Pb retention on forest soil, vineyard soil, and pyritic material samples, as well as on fine mussel shell, oak ash, hemp waste and pine bark samples, differentiating between results corresponding to the individual materials and those corresponding to the soils and pyritic material amended with the by-products.…”