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Graphitic Carbon Nitride and Nickel-Doped Graphitic Carbon Nitride for Doxycycline Removal: Adsorption Efficiency and Mechanistic Insights

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Adsorption is a simple yet effective technique for the removal of emerging contaminants. In this study, pure graphitic carbon nitride (g-C 3 N 4 ) and nickel-doped g-C 3 N 4 (Ni- g -C 3 N 4 ) were synthesized via a thermal polycondensation method and evaluated as adsorbents for doxycycline removal. Structural and morphological characterization was performed using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy. The results confirmed the successful incorporation of Ni 2+ into the g-C 3 N 4 matrix, with homogeneous Ni 2+ distribution and no secondary phases. Morphological analysis indicated that nickel doping induced only slight changes in the g-C 3 N 4 morphology. Adsorption experiments revealed that both materials exhibited enhanced adsorption capacity at pH 9, with Ni- g -C 3 N 4 achieving a significantly higher removal efficiency (53.4%) compared to g-C 3 N 4 (14.2%). This improvement was attributed to Ni 2+ -induced positively charged regions, facilitating stronger adsorbate–adsorbent interactions. Kinetic analysis demonstrated that doxycycline adsorption onto Ni- g -C 3 N 4 followed a pseudo-second-order model. Among the tested isotherm models, the Sips model provided the best fit, yielding maximum adsorption capacities of 37.889 mg·g –1 for g-C 3 N 4 and 116.265 mg·g –1 for Ni- g -C 3 N 4 . Theoretical calculations corroborated experimental findings, confirming that Ni 2+ incorporation in the g-C 3 N 4 structure enhances adsorption capacity by facilitating strong chemical bonds between doxycycline and the Ni- g -C 3 N 4 adsorbent surface.

Source: Langmuir

DOI: 10.1021/acs.langmuir.5c03760

Authors: Daniela Cristina Feitosa Angelo, Raíssa Santos Sousa, Rafael Meuredi Pinheiro Souza, Douglas Henrique Pereira, Gleice Botelho

Institutions: Universidade Federal do Tocantins, Instituto Tecnológico de Aeronáutica

Language: English

Topic: Adsorption and biosorption for pollutant removal

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,500