Simultaneous removal of Cd, Co, Cu, Mn, Ni and Zn from synthetic solutions on a hemp‐based felt: Experimental design

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Two hemp‐based materials were used as nonconventional adsorbents for the final treatment of industrial discharge waters (DWs) from a metal‐finishing plant. The first adsorbent, referred as HEMP, was a felt made of 100% hemp fiber. The second was the same felt coated with a maltodextrin‐1,2,3,4‐butanetetracarboxylic crosslinked polymer (HEMPM) in order to provide ion‐exchange properties to the material by introducing carboxylic groups. The batch experiments showed that both materials exhibited high adsorption capacities toward metal ions present in 12 DWs, leading to concentrations well below those allowed by the French regulation. Measurements of the germination rate of Lactuca sativa seeds and of mobility inhibition of Daphnia magna, used as ecotoxicological tests, were carried out on DWs before and after hemp treatment. The average germination rate before and after treatment were 47.2 ± 4.1 for untreated DWs, 71.2 ± 6.3 for DWs treated by HEMP, and 89.3 ± 4.7 for DWs treated by HEMPM. The EC50 values for four DWs were between 2.1 and 10.4% of DW, indicating high toxicity. After HEMPM treatment, exposure to the DW for 24 h did not cause immobilization (EC50 > 90%). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48823.

Section: Introductionmentioning

confidence: 57%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Simultaneous removal of Cd, Co, Cu, Mn, Ni, and Zn from synthetic solutions on a hemp‐based felt. III. Real discharge waters

Morin‐Crini

Staelens

Loiacono

et al. 2019

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Simultaneous removal of Cd, Co, Cu, Mn, Ni, and Zn from synthetic solutions on a hemp‐based felt. II. Chemical modification

Loiacono

Crini

Martel

et al. 2017

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International audienceIn this study, we propose a chemical pretreatment to improve the performance of a hemp-based material in felt formused as an adsorbent for removing the metals from aqueous mixtures of Cd, Co, Cu, Mn, Ni, and Zn. The felt was coated with amaltodextrin-1,2,3,4-butane tetracarboxylic polymer in order to provide ion-exchange properties to the material by introducing carboxylicgroups. It was characterized by solid-state 13 C-NMR technique and by Energy-dispersive X-ray spectroscopy. This new adsorbentwas then used in batch experiments and its performances were compared with those of non-modified hemp. Differentcontrolling experimental conditions have been investigated. Modified hemp exhibited strong adsorption capacities due to a chemisorptionmechanism (complexation, ion exchange): up to 25 mg/L (in reality, 150 mg of metals per L), all metals in the solutionwere removed. A modified hemp dosage of 1 g was able to remove 13.91 mg of metals in 100 mL of solution at a concentration of25 mg/L for each metal, whereas non-modified hemp only removed 7.4 mg in the same experimental conditions. Adsorption of metalsreached equilibrium in 60 min and the performances were pH-independent between 3 and 6, but dependent on the presence ofNaCl, except for Cu

Dithiocarbamate functionalized Al(OH)₃‐polyacrylamide adsorbent for rapid and efficient removal of Cu(II) and Pb(II)

Liu

Qian

Yang

et al. 2017

Heavy metal ions such as Cu2+ and Pb2+ impose a significant risk to the environment and human health due to their high toxicity and non‐degradable characteristics. Herein, Al(OH)3‐polyacrylamide chemically modified with dithiocarbamates (Al‐PAM‐DTCs) was synthesized using formaldehyde, diethylenetriamine, carbon disulfide, and sodium hydroxide for rapid and efficient removal of Cu2+ and Pb2+. The synthesized adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, scanning electron microscopy–energy dispersive X‐ray spectroscopy analysis, and transmission electron microscope measurements. Al‐PAM‐DTCs showed rapid removal of Cu2+ (<30 min) and Pb2+ (<15 min) with high adsorption capacities of 416.959 mg/g and 892.505 mg/g for Cu2+ and Pb2+ respectively. Al‐PAM‐DTCs also had high capacities in removing suspended solids and metal ions simultaneously in turbid bauxite suspensions. FTIR, thermodynamic study, and elemental mapping were used to determine the adsorption mechanism. The rapid, convenient, and effective adsorption of Cu2+ and Pb2+ indicated that Al‐PAM‐DTCs has great potential for practical applications in purification of other heavy metal ions from aquatic systems. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45431.