Extraction of precious metals from industrial solutions by the pine ( Pinus sylvestris ) sawdust-based biosorbent modified with thiourea groups

Лосев, В. Н.; Elsufiev, Eugene V.; Buyko, Olga V.; Трофимчук, А. К.; Horda, R.V.; Legenchuk, O.V.

doi:10.1016/j.hydromet.2018.01.016

Cited by 46 publications

(11 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Firstly, NH 4 SCN postpones the rising pHRR as a suitable O 2 − consuming reductant. NH 4 SCN with a melting temperature of 149.6 • C can transform into thiourea at 140~180 • C [22], the strong alkaline condition triggers the prior oxidizing reaction and the firing provides the conditions for the formation of sulfate, this implies that the phase change performance of NH 4 SCN is limited or inhibited, but the reducibility is beneficial for retarding flame-propagation by consuming O 2 . Secondly, NH 4 SCN mainly favors the formation of a continuous layer as a dopant for reinforcing the siliceous layer, due to its natural amorphousness [32], which facilitates its diffusion and migration in the amorphous geopolymeric coatings, and the formation of carbonate and sulfate prompts a continuous and compact siliceous layer as a barrier filler.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, the heat absorption of S5 decreased slightly and a tiny left-shift of the peak temperature occurred compared with that of S2 as shown in Figure 6. It has been reported that the transformation of NH 4 SCN into thiourea occurs at approximately 140 • C [22,23], no endothermic peak appeared at 140 • C, implying that the NH 4 SCN reacted under strong alkaline conditions. Due to its high solubility and ionized NH 4 + , the prior reaction between NH 4 + and OH − occurs with heat released, leading to a slight decrease in absorption heat, evidenced by the shrunken area h S5 (224.1 J•g −1 ) of the endothermic peak in comparison to h S2 (297.6 J•g −1 ).…”

Section: Tg/dscmentioning

confidence: 96%

See 1 more Smart Citation

Ecological Ammonium Thiocyanate-Modified Geopolymeric Coating for Flame-Retarding Plywood

Wang

Zhao

2019

Coatings

View full text Add to dashboard Cite

An ecological ammonium thiocyanate (NH4SCN)-modified geopolymeric coating was facilely prepared for flame-retarding plywood. The effect of NH4SCN on the flame resistance was preliminarily investigated using cone calorimeter (CC), scanning electron microscope (SEM), X-ray diffraction (XRD), and thermal gravimetry (TG). The results show that 1 wt.% NH4SCN as dopant is of paramount importance to generate a compact and continuous coating. The formation of a smooth, intact, and uniform-swelling siliceous layer during combustion facilitates enhanced fire resistance, evidenced by the increased fire performance index (FPI), reduced fire growth index (FGI), and 39.7% decreased value of peak heat release rate (pHRR), in comparison to those of the sample without NH4SCN. Because of the reducibility of O2-consuming NH4SCN, the compact shielding-layer containing carbonate and sulfate, as well as the release of NH3, the NH4SCN-modified geopolymeric coating exerts an enhancement on the flame-retardant efficiency.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Tg/dscmentioning

confidence: 96%

Ecological Ammonium Thiocyanate-Modified Geopolymeric Coating for Flame-Retarding Plywood

Wang

Zhao

2019

Coatings

View full text Add to dashboard Cite

show abstract

“…For example, Mallakpour et al developed a new hydrogel nanocomposite biosorbent by embedding calcium carbonate nanoparticles into tragacanth gum for the removal of Pb 2+ ions from water samples [230]. Similarly, pine (Pinus sylvestris) sawdust was modified with thiourea groups and utilized for the extraction of precious metals from industrial solutions [231]. Table 9 shows additional examples of recently reported natural biosorbent materials for extraction of metals.…”

Section: Biosorbent Extractionmentioning

confidence: 99%

Evolution of Environmentally Friendly Strategies for Metal Extraction

et al. 2020

View full text Add to dashboard Cite

The demand for the recovery of valuable metals and the need to understand the impact of heavy metals in the environment on human and aquatic life has led to the development of new methods for the extraction, recovery, and analysis of metal ions. With special emphasis on environmentally friendly approaches, efforts have been made to consider strategies that minimize the use of organic solvents, apply micromethodology, limit waste, reduce costs, are safe, and utilize benign or reusable materials. This review discusses recent developments in liquid- and solid-phase extraction techniques. Liquid-based methods include advances in the application of aqueous two- and three-phase systems, liquid membranes, and cloud point extraction. Recent progress in exploiting new sorbent materials for solid-phase extraction (SPE), solid-phase microextraction (SPME), and bulk extractions will also be discussed.

show abstract

“…This can be achieved by selecting suitable chelating agents. The chelating groups that are widely used for preconcentration of precious metals are imidazole, thioguanidine, dithizone, mercapto groups, amino groups, and thioureas [ 18 ]. In several studies, N, N-diethyl-N'-benzoylthiourea (DEBT) has been recorded as a selective complexing agent for precious metals [ 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Selective Preconcentration of Gold from Ore Samples

Refiker

Merdıvan

Aygün

2018

International Journal of Analytical Chemistry

View full text Add to dashboard Cite

A simple and selective method has been developed for preconcentration of gold in ore samples. The method is based on use of N, N-diethyl-N'-benzoylthiourea (DEBT) as selective chelating agent and Amberlite XAD-16 as solid sorbent. Sorption behavior of gold with DEBT impregnated resin under optimized conditions has been studied in batch process. The gold ion capacity of the impregnated resin is calculated as 33.48 mg g−1 resin (0.17 mmol g−1 resin). The selective preconcentration of metal was examined using gold chelates prepared in column process under optimized conditions: pH, flow rate, volume of sample solution, nature of eluent, flow rate, and volume of eluent. Under optimum conditions, gold ions at the concentration of 0.015 μg mL−1 with a preconcentration factor of 6.7 have been determined by flame atomic absorption spectrometry (FAAS). The accuracy of the proposed method was validated by the analysis of a Cu-ore (semi-certified) supplied by CMC (Cyprus Mining Company, North Cyprus) and a certified reference material, Gold Ore (MA-1b Canmet-MMSL). Satisfactory results were obtained with a RSD of 7.6%. The highly selective proposed method does not require any interference elimination process.

show abstract

Extraction of precious metals from industrial solutions by the pine ( Pinus sylvestris ) sawdust-based biosorbent modified with thiourea groups

Cited by 46 publications

References 35 publications

Ecological Ammonium Thiocyanate-Modified Geopolymeric Coating for Flame-Retarding Plywood

Ecological Ammonium Thiocyanate-Modified Geopolymeric Coating for Flame-Retarding Plywood

Evolution of Environmentally Friendly Strategies for Metal Extraction

Selective Preconcentration of Gold from Ore Samples

Contact Info

Product

Resources

About