Natural Adsorbents Derived from Tannin Extracts for Pharmaceutical Removal in Water

Abstract

Novel adsorbents can be synthesized through tannin gelation, and they are effective agents for the removal of specific contaminants, for example the pharmaceutical species Trimethoprim. The current paper presents an optimization process for obtaining the best adsorbent from four tannin feedstock: Acacia mearnsii de Wild, Schinopsis balansae, Cupressus sempervivens, and Pinus pinaster bark extract. The cross-linking was undergone with formaldehyde and acetaldehyde, hence the type of aldehyde and its concentration in the gelation mixture were considered operative variables as well as the tannin source. The best categories resulted to be Cupressus sempervivens and Pinus pinaster with formaldehyde (3.68 mmol pure formaldehyde per g of of tannin extract) and Schinopsis balansae with diluted formaldehyde (1 mmol of pure formaldehyde per g of tannin extract). Tannin-derived rigid gels were very effective adsorbents for the removal of this dangerous pharmaceutical: trimethoprim, with maximum adsorption capacities even higher than 300 mg of trimethoprim per g of adsorbent.

Tannin-based biosorbents for environmental applications – A review

“…Removal of TMP from water was studied using a cypress tannin gel [76] and a tannin rigid foam (from Weibull black) [51]. TMP adsorptive removal is little affected by pH conditions, with removal percentages between 52 and 63%, at pH range 3-9, when a TMP solution of 50 mg L À1 was used, and 0.25 g L À1 of adsorbent dosage [51].…”

Diclofenac removal in urine using strong-base anion exchange polymer resins

“…Sorption processes are attractive for removal of pharmaceuticals because they are low energy, can be used on continuous-flow or batch basis, can be used in different reactor configurations including mixed slurry or fixed bed, and have the option to either regenerate and reuse the sorbent or dispose of the sorbent after complete exhaustion (Crittenden et al, 2012). Recent research on pharmaceutical removal using sorption has evaluated activated carbon (Rossner et al, 2009), mesoporous silica (Bui and Choi, 2009;Turku et al, 2007), polymer resins (Dominguez et al, 2011;Bä uerlein et al, 2012;Huang et al, 2012;Hu et al, 2012), molecularly imprinted polymers (Dai et al, 2011), and natural materials (Beltran-Heredia et al, 2012). For example, sorption of acidic, basic, and neutral pharmaceuticals in ultrapure water onto a nonionic polyacrylic resin showed the highest removal when the pharmaceutical was uncharged, which indicates non-electrostatic interactions, i.e., hydrogen bonding and van der Waals forces control the sorption process (Dominguez et al, 2011).…”

Extraction Temperature Effect in Modification of Nephelium Tannin Based Biosorbent

“…FTIR spectra were NTBB 1 (tannin extract from room temperature), NTBB 2 (tannin extract from 50 °C), NTBB 3 (tannin extract from 70 °C) and NTBB 4 (tannin extract from 80 °C). Polymerization process of extract tannin with aldehyde compound showed that the polymer compound of NTBB been formed as indicated by the appearance of absorption peaks at 1074-1069 cm -1 and which is the vibration of C-O ether group as methylene ether bridge [12]. NTBB 3 and NTBB 4 have absorption peak at 2362-2360 cm -1 .…”

“…Tannin can be applied to various fields such as pharmaceutical compounds for the removal of antibiotic trimethoprim (TMP) [12], chemistry as a substitute for phenol in phenolformaldehyde resins [7] and as adsorbent heavy metals such as cadmium in fish sauce [13] as well as inhibitors of metal corrosion rate [9].…”