Fabricating whole pine needles biomass with phenylhydrazine-4-sulphonic acid for effective removal of cationic dyes and heavy metal ions from wastewater

• Published in: Chemosphere (Oxford) 2024-09, Vol.364, p.143103, Article 143103
• Main Authors: Kumari, Babita, Chauhan, Sandeep, Kumar, Kiran, Singh, Sudershan, Ranote, Sunita, Kumar, Rajesh, Chauhan, Ghanshyam S.
• Format: Article
• Language: English
• Subjects: Phenylhydrazine-4-sulphonic acid; Pine needles; Rapid adsorption; Reusability; Schiff base; Sustainable adsorbent
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2024.143103

We applied a holistic, sustainable, and green approach to develop an effective multipurpose adsorbent from whole pine needles (PNs), a forest waste lignocellulosic biomass. The PNs were oxidized and modified with phenylhydrazine-4-sulphonic acid (ɸHSO3H) to OPN-ɸHSO3H. The latter was characterized and tested as an adsorbent for cationic dyes, malachite green (MG), methylene blue (MB), crystal violet (CV), and metal ions (Hg2⁺ and Pb2⁺). The adsorption followed different kinetic models: Elovich for MG and MB, pseudo-second-order for CV, and pseudo-first-order for Hg2⁺ and Pb2⁺. Langmuir isotherm indicated maximum adsorption capacities of 303.4 ± 8.91 mgg−1 (MG), 331.4 ± 17.50 mgg−1 (MB), 376.6 ± 22.47 mgg−1 (CV), 210.8 ± 28.86 mgg−1 (Hg2⁺), and 172.9 ± 20.93 mgg−1 (Pb2⁺) within 30 min. Maximum removal efficiencies were 99.0% (MG), 98.0% (MB), 96.04% (CV), 95.5% (Hg2⁺), and 89.8% (Pb2⁺). The adsorbent demonstrated significant regeneration and reusability over ten cycles, proving highly efficient for both cationic dyes and metal ions, with wide potential for practical applications where more than one adsorbate is present. [Display omitted] •Pine needles (PN) were oxidized in two steps with TEMPO, and NaIO4.•-CHO of OPN reacted with phenylhydrazine-4-sulphonic acid to form Schiff-base.•Schiff-base proved selective adsorbent for MB, CV, MG, Hg2+, and Pb2+ ions.•Adsorption was highly rapid and efficient with high adsorption capacity.•High adsorption capacity even after ten cycles of regeneration and reusability.