Application of a cashew-based oxime in extracting Ni, Mn and Co from aqueous solution

Abstract

Background Cashew nut shell is a by-product of cashew (Anacardium occidentale) production, which is abundant in many developing countries. Cashew nut shell liquor (CNSL) contains a functional chemical, cardanol, which can be converted into a hydroxyoxime. The hydroxyoximes are expensive reagents for metal extraction. Methods CNSL-based oxime was synthesized and used to extract Ni, Co, and Mn from aqueous solutions. The extraction potential was compared against a commercial extractant (LIX 860N). Results All metals were successfully extracted with pH0.5 between 4 and 6. The loaded organic phase was subsequently stripped with an acidic solution. The extraction efficiency and pH0.5 of the CNSL-based extractant were similar to a commercial phenol-oxime extractant. The metals were stripped from the loaded organic phase with a recovery rate of 95% at a pH of 1. Conclusions Cashew-based cardanol can be used to economically produce an oxime in a simple process. The naturally-based oxime has the economic potential to sustainably recover valuable metals from spent lithium-ion batteries. Graphic abstract

Synthesis of a Grease Thickener from Cashew Nut Shell Liquor

“…The 1 H NMR spectrum shows the characteristic signals of the olefinic double bond at 4.8-6.0 ppm, as well as the H bonded to the aromatic ring at 6.5 to 7.5 ppm (Figure 6). Collectively, 13 C and 1 H NMR measurements indicate a signal of the anacardic acid moiety in the product [26]. It is important to note that the method does not require the full hydrogenation of anacardic acids.…”

“…It can be seen that the 1488 cm −1 disappeared after 1 h. Consequently, the required reaction for this process should be at least 1 h. ring at 6.5 to 7.5 ppm (Figure 6). Collectively, 13 C and 1 H NMR measurements indicate a signal of the anacardic acid moiety in the product [26]. It is important to note that the method does not require the full hydrogenation of anacardic acids.…”

“…The obtained anacardic acids were analyzed by FTIR, 13 C NMR and 1 H NMR. In Figure 4, the peak at 1452 cm −1 is be shown as aromatic ring vibrations (including valence vibrations of C=C and strain vibrations of =C-H).…”

“…Anacardic acid tends to decarboxylate into cardanol at high temperature [20]. Analysis of the 13 C NMR nuclear magnetic resonance spectrum of anacardic acid showed a signal display with a chemical shift at 175 ppm corresponding to the carbonyl group of the carboxylic acid (Figure 5). The 1 H NMR spectrum shows the characteristic signals of the olefinic double bond at 4.8-6.0 ppm, as well as the H bonded to the aromatic ring at 6.5 to 7.5 ppm (Figure 6).…”

“…However, the specific components of liquor have different physical properties and can be used as specialized chemicals. The most well-known chemical that cashew nut shell liquor contains is cardanol, which can be converted into industrial chemicals such as extractants [12,13] and surfactants [14]. The molecular structure of natural cardanols offers comparable physio-chemical properties to petroleum-based organic reagents [15].…”