Residual biomass of coffee as a binding agent in diffusive gradients in thin-films technique for Cd, Cu, Ni, Pb and Zn measurement in waters

Abstract

Spent coffee grounds (SCG) immobilized in agarose gel are proposed as a novel binding agent for application in the Diffusive Gradients in Thin films (DGT) technique for the determination of Cd, Cu, Ni, Pb and Zn in waters. The SCG-agarose gel was characterized by Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry and Porosimetry by nitrogen adsorption. Elution of analytes from the binding agent was effectively performed with 2 mol L −1 HCl. The effects of key DGT parameters (e.g. immersion time, ionic strength and pH) were evaluated with a deployment of DGT devices (DGT-SCG) in synthetic solutions with ionic strengths between 0.005 mol L-1 and 0.1 mol L-1 and within a pH range of 3.5 to 8.0. The results were in excellent agreement with the predicted theoretical curve for mass uptake. Consistent results were found for solutions with ionic strengths between 0.005 mol L-1 and 0.1 mol L-1 and within a pH range of 3.5 to 8.0. The DGT-SCG performance was also evaluated in two spiked river water samples (Corumbataí and Piracicaba river) with satisfactory uptake values (C DGT-SCG /C sol) between 0.74 to 1.53. The proposed DGT-SCG opens opportunities for using residual biomass as binding phase in the DGT technique, showing low costs in production and complying with "green" technology approaches.

Determination of Labile Cadmium in Soils Using a New Sodium Alginate‐Polyglutamic Acid‐Diffusive Gradient in Thin Films

“…We chose 3 M HNO 3 as the best eluent for use in the present study. The elution efficiency of Cd was 98 ± 0.9%, which was higher than that of novel spent coffee grounds gel (eluting efficiency 62.9 ± 3.7%; Yabuki et al 2019) and traditional Chelex-100 gel (eluting efficiency 83.9 ± 2.7%; Zhang and Davison 1995). Not only that, SA-PGA gel with higher eluting efficiency was more helpful for the capture and determination of target substance more accurately.…”

“…The pH ranged from 5 to 9, the Cd adsorption efficiency of the DGT did not change significantly, and the value of C DGT /C soln tended to 1 (Supplemental Data, Figure S2A). Regarding DGT for the same metal target, conclusions can be drawn; SA‐PGA‐DGT is applied to a wider pH range than Saccharomyces cerevisiae DGT (pH 4.5–7.5), spent coffee grounds DGT (pH 3.5–8.0), and poly(ethyleneimine) and 2‐pyridinecarboxaldehyde DGT (pH 4–8.5; Menegario et al 2010; Fan et al 2013; Yabuki et al 2019). Compared with the reported pH range of Chelex‐100 resin (Zhang and Davison 1995), the quantitative binding of SA‐PGA‐DGT at pH 5 to 9 was equally reliable.…”

“…S2A). Regarding the DGT for the same metal target, conclusions can be drawn, SA-PGA-DGT is applied to a wider pH range than S. cerevisiae DGT (pH 4.5-7.5), Spent coffee grounds DGT (pH 3.5-8.0) and Py-PEI DGT (pH 4-8.5) (Fan 2013;Menegario 2010;Yabuki 2019). Compared with the reported pH range of Chelex-100 resin (Zhang and Davison 1995), the quantitative binding of SA-PGA-DGT at pH (5-9) was equally reliable.…”

“…Wang et al (2018) developed a new binding gel with micro‐/nanostructured porous ZnO for Cu (II) measurement. Yabuki et al (2019) utilized spent coffee grounds as a new binding gel in DGT, measuring Cd, Cu, Ni, Zn, and Pb. In recent years, DGT used in soil and sediment has been continuously developed.…”

PAMPS-graft-Ni3Si2O5(OH)4 multiwalled nanotubes as a novel nano-sorbent for the effective removal of Pb(ii) ions

“…[12][13][14] Various adsorbents, including biomass, polymers, activated carbons and minerals, have been applied to remove Pb(II) from contaminated wastewater. [14][15][16][17] Moreover, it has been observed that these adsorbents require further modications to increase the number of active binding sites and make them readily available for adsorption. 18,19 Although some of the abovementioned adsorbents are able to remove Pb(II) from contaminated wastewater, high cost is still the main concern or disadvantage of these adsorbents in practical applications.…”