Removal of Heavy Metal Ions from Wastewaters: An Application of Sodium Trithiocarbonate and Wastewater Toxicity Assessment

Abstract

The synthesis and application of sodium trithiocarbonate (Na2CS3) for the treatment of real galvanic wastewater in order to remove heavy metals (Cu, Cd and Zn) was investigated. A Central Composite Design/Response Surface Methodology (CCD/RSM) was employed to optimize the removal of heavy metals from industrial wastewater. Adequacy of approximated data was verified using Analysis of Variance (ANOVA). The calculated coefficients of determination (R2 and R2adj) were 0.9119 and 0.8532, respectively. Application of Na2CS3 conjugated with CCD/RSM allowed Cu, Cd and Zn levels to be decreased and, as a consequence, ∑Cu,Cd,Zn decreased by 99.80%, 97.78%, 99.78%, and 99.69%, respectively, by using Na2CS3 at 533 mg/L and pH 9.7, within 23 min. Implementation of conventional metal precipitation reagents (NaOH, Ca(OH)2 and CaO) at pH 11 within 23 min only decreased ∑Cu,Cd,Zn by 90.84%, 93.97% and 93.71%, respectively. Rotifer Brachionus plicatilis was used to conduct the assessment of wastewater toxicity. Following the application of Na2CS3, after 60 min the mortality of B. plicatilis was reduced from 90% to 25%. Engagement of Na2CS3 under optimal conditions caused the precipitation of heavy metals from the polluted wastewater and significantly decreased wastewater toxicity. In summary, Na2CS3 can be used as an effective heavy metal precipitating agent, especially for Cu, Cd and Zn.

Sodium trithiocarbonate cathode for high-performance sodium–sulfur batteries

“…Na 2 CS 3 has been reported as an effective precipitating agent to remove heavy metals from galvanic wastewater for decades. 40,41 Trithiocarbonates can be easily formed from a reaction between carbon disulde (CS 2 ) and other sulde sources. [42][43][44] Here, the synthesis of Na 2 CS 3 was carried out by a one-step wet ball milling of sodium sulde (Na 2 S), and an excess amount of CS 2 in a mole ratio of 1 : 3.…”

Environmental and human health implications of metal(loid)s: Source identification, contamination, toxicity, and sustainable clean-up technologies

“…The metal hydroxides that are inexplicable in the alkaline medium are increased when the pH is changed. For metal(loid)s removal, layered double hydroxides are produced in the case of trivalent ions (Thomas et al, 2021). To create a hydroxide precipitate, several precipitants such as lime, calcium hydroxide, ammonium hydroxide, and sodium hydroxide are presented.…”

Removal of Zinc from Concentrated Galvanic Wastewater by Sodium Trithiocarbonate: Process Optimization and Toxicity Assessment

“…Recent studies have shown that polluted waters or industrial wastewaters may contain varying amounts of zinc, for example, 52.8 mg/L (electroplating company, Atom, Dubna, Russia) [ 14 ], 10 mg/L, being approximately 80% and 20% in the form of Zn 2+ and ZnSO 4 (aq), respectively [ 15 ], 33.3 g/L (spent acid solution from the pickling stage of a galvanizing plant) [ 16 ], 1392.1 mg/L (zinc plating industry) [ 17 ], 22.7 mg/L (galvanic wastewater) [ 18 ] and 49.8 mg/L (zinc electroplating industry) [ 19 ].…”

“…It consists of the use of alkaline reagents (NaOH, CaO, Ca(OH) 2 and Na 2 CO 3 ) for the precipitation of sparingly soluble metal hydroxides in which its solubility depends on the pH of the wastewater. However, this method has some limitations, i.e., using high doses of alkaline reagents, large volumes of sludge and limited effectiveness in the case of amphoteric hydroxides and in the presence of complexing compounds [ 18 , 26 , 27 , 28 , 29 , 30 , 31 ]. In these cases, additional precipitants are used to ensure that the concentration of metals in the wastewater treatment is reduced to the legal requirements.…”