A two-in-one thiosemicarbazide and whole pine needle-based adsorbent for rapid and efficient adsorption of methylene blue dye and mercuric ions

• Published in: Environmental science and pollution research international 2024-03, Vol.31 (14), p.21591-21609
• Main Authors: Kumari, Babita, Chauhan, Sandeep, Chauhan, Ghanshyam S., Kumar, Kiran, Jamwal, Pooja, Ranote, Sunita
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Biodegradation; Cationic dyes; Color removal; Correlation coefficient; Correlation coefficients; Crystallinity; Dyes; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Imines; Industrial effluents; Industrial wastewater; Isotherms; Mercury (metal); Metal ions; Methylene blue; Oxidation; Pine needles; Recyclability; Research Article; Stretching; Surface charge; Textile industry wastes; Textile industry wastewaters; Thiosemicarbazides; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-32446-3

Herein, we report the synthesis of an oxidized pine needle-thiosemicarbazone Schiff base (OPN-TSC) from whole pine needles (WPN) as a dual-purpose adsorbent to remove a cationic dye, methylene blue (MB), and Hg 2+ ions in separate processes. The adsorbent was synthesized by periodate oxidation of WPN followed by a reaction with thiosemicarbazide. The syntheses of OPN and OPN-TSC were confirmed by FTIR, XRD, FESEM, EDS, BET, and surface charge analysis. The emergence of new peaks at 1729 cm −1 (–CHO stretching) and 1639 cm −1 (–COO − stretching) in the FTIR spectrum of OPN confirmed the oxidation of WPN to OPN. FTIR spectrum of OPN-TSC has a peak at 1604 cm −1 (C = N stretching), confirming the functionalization of OPN to OPN-TSC. XRD studies revealed an increase in the crystallinity of OPN and a decrease in the crystallinity of OPN-TSC because of the attachment of thiosemicarbazide to OPN. The values of %removal for MB and Hg 2+ ions by OPN-TSC were found to be 87.36% and 98.2% with maximum adsorption capacity of 279.3 mg/g and 196 mg/g for MB and Hg 2+ ions, respectively. The adsorption of MB followed pseudo-second-order kinetics with correlation coefficient ( R 2 of 0.99383) and Freundlich isotherm ( R 2  = 0.97239), whereas Hg 2+ ion removal demonstrated the Elovich ( R 2  = 0.97076) and Langmuir isotherm ( R 2  = 0.95110). OPN-TSC is regenerable with significant recyclability up to 10 cycles for both the adsorbates. The studies established OPN-TSC as a low-cost, sustainable, biodegradable, environmentally benign, and promising adsorbent for the removal of hazardous cationic dyes and toxic metal ions from wastewater and industrial effluents, especially the textile effluents. Graphical abstract