“…Surface water quality is affected by DOM concentrations which may pose undesired color, taste, and odor in drinking water (Kenefick et al, 1992;Mallevialle and Suffet, 1987). Furthermore, it forms complexes with many organic and inorganic pollutants (Aiken et al, 2011;Ding et al, 2019;Lubal et al, 1998;Mei et al, 2016;Senesi and Chen, 1989). In water treatment facilities DOM brings upon several problems, mainly the enhancement of biofilms growth on pipelines and membranes (Herzberg and Elimelech, 2007;Katz et al, 2014;Schneider et al, 2005;Tarchitzky et al, 2013).…”
“…Surface water quality is affected by DOM concentrations which may pose undesired color, taste, and odor in drinking water (Kenefick et al, 1992;Mallevialle and Suffet, 1987). Furthermore, it forms complexes with many organic and inorganic pollutants (Aiken et al, 2011;Ding et al, 2019;Lubal et al, 1998;Mei et al, 2016;Senesi and Chen, 1989). In water treatment facilities DOM brings upon several problems, mainly the enhancement of biofilms growth on pipelines and membranes (Herzberg and Elimelech, 2007;Katz et al, 2014;Schneider et al, 2005;Tarchitzky et al, 2013).…”
“…These changes in the FTIR peaks after the adsorption of lithium ions indicate that the specific molecules were involved directly and played a role in the adsorption process. In other words, the uptake of lithium ions by the adsorbent resulted in an altered composition of the adsorbent, which means that these functional groups are important to be present for the adsorption to be efficient 51 – 53 . Figure 6 ( A ) FTIR spectra before and after the adsorption of lithium onto RDP, ( B ) RDP-FC-Cu, and ( C ) RDP-FC-Ni.…”
In this paper, novel composite materials from modified roasted date pits using ferrocyanides were developed and investigated for the recovery of lithium ions (Li+) from seawater reverse osmosis (RO) brine. Two composite materials were prepared from roasted date pits (RDP) as supporting material, namely potassium copper hexacyanoferrate-date pits composite (RDP-FC-Cu), and potassium nickel hexacyanoferrate-date pits composite (RDP-FC-Ni). The physiochemical characterization of the RO brine revealed that it contained a variety of metals and salts such as strontium, zinc, lithium, and sodium chlorides. RDP-FC-Cu and RDP-FC-Ni exhibited enhanced chemical and physical characteristics than RDP. The optimum pH, which attained the highest adsorption removal (%) for all adsorbents, was at pH 6. In addition, the highest adsorption capacities for the adsorbents were observed at the initial lithium concentration of 100 mg/L. The BET surface area analysis confirmed the increase in the total surface area of the prepared composites from 2.518 m2/g for RDP to 4.758 m2/g for RDP-FC-Cu and 5.262 m2/g for RDP-FC-Ni. A strong sharp infrared peak appeared for the RDP-FC-Cu and RDP-FC-Ni at 2078 cm−1. This peak corresponds to the C≡N bond, which indicates the presence of potassium hexacyanoferrate, K4[Fe(CN)6]. The adsorption removal of lithium at a variety of pH ranges was the highest for RDP-FC-Cu followed by RDP-FC-Ni and RDP. The continuous increase in the adsorption capacity for lithium with increasing initial lithium concentrations was also observed. This could be mainly attributed to enhance and increased lithium mass transfer onto the available adsorption active sites on the adsorbents’ surface. The differences in the adsorption in terms of percent adsorption removal were clear and significant between the three adsorbents (P value < 0.05). All adsorbents in the study showed a high lithium desorption percentage as high as 99%. Both composites achieved full recoveries of lithium from the RO brine sample despite the presence of various other competing ions.
“…Humic substances in soils are naturally associated with metal ions (Stevenson, 1994;Ghosh and Schnitzer, 1981; Yan and Korshin, 2014;Zhou et al, 2015;Ding et al, 2019) and the phenomenon is more pronounced with tropical soils. However, most of the studies on humic substances have been made with samples of temperate origin although it was known that the characteristics of tropical samples are different (Gri th & Schnitzer, 1975).…”
In the present study, an attempt has been made to probe the nature of silicon-humus bonding as it occurs in nature ('untreated') as compared to the samples wherefrom the metalloid ions have been removed ('treated'). Infrared (IR) spectroscopy revealed the role of carboxylic acid groups of Humic acid (HA) in metal complexation. Si-O absorption reduced considerably in treatment to remove metalloid ions, but it remained quite strong in the treated samples indicating a strong Si-O linkage with humus. In XRD analysis, treated samples showed stronger γ-bands. DTA analysis indicated structural strain on the humic molecule induced by complexation with metalloid ions. Treated HAs had higher acidity values compared to the untreated samples. Treatment for removal of metal ions caused an increase in cation exchange capacity while a reduction of E4/E6 ratio. Treated HAs also showed higher molecular weights (Mv) compared to the untreated samples. Removal of metals renders certain groups free which form intermolecular bonds. On the basis of analytical data, it was observed that there is still some silicon bonds within humic acid molecule, even after removal of silicon by forcing conditions. Association of silicon with humus in soils are quantitatively and qualitatively different from other metal ions and it is clear that humic acid molecule possess silicon-humus bond like pure organo-metallic compounds.
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