Novel hydrophilic straw biochar for the adsorption of neonicotinoids: kinetics, thermodynamics, influencing factors, and reuse performance

Recent advances and prospects of neonicotinoid insecticides removal from aquatic environments using biochar: Adsorption and degradation mechanisms

In recent years, neonicotinoid insecticides (NNIs), representing a new era of pest control, have increasingly replaced traditional classes such as organophosphorus compounds, carbamates, and pyrethroids due to their precise targeting and broad-spectrum efficacy. However, the high water solubility of NNIs has led to their pervasion in aquatic ecosystems, raising concerns about potential risks to non-target organisms and human health. Therefore, there is an urgent need for research on remediating NNI contamination in aquatic environments. This study demonstrates that biochar, characterized by its extensive surface area, intricate pore structure, and high degree of aromaticity holds significant promise for removing NNIs from water. The highest reported adsorption capacity of biochar for NNIs stands at 738.0 mg·g-1 with degradation efficiencies reaching up to 100.0 %. This review unveils that the interaction mechanisms between biochar and NNIs primarily involve π-π interactions, electrostatic interactions, pore filling, and hydrogen bonding. Additionally, biochar facilitates various degradation pathways including Fenton reactions, photocatalytic, persulfate oxidations, and biodegradation predominantly through radical (such as SO4-, OH, and O2-) as well as non-radical (such as 1O2 and electrons transfer) processes. This study emphasizes the dynamics of interaction between biochar surfaces and NNIs during adsorption and degradation aiming to elucidate mechanistic pathways involved as well as assess the overall efficacy of biochar in NNI removal. By comparing the identification of degradation products and degradation pathways, the necessity of advanced oxidation process is confirmed. This review highlights the significance of harnessing biochar's potential for mitigating NNI pollution through future application-oriented research and development endeavors, while simultaneously ensuring environmental integrity and promoting sustainable practices.

Imidacloprid removal by modified graphitic biochar with Fe/Zn bimetallic oxides

Coping with the critical challenge of imidacloprid (IMI) contamination in sewage treatment and farmland drainage purification, this study presents a pioneering development of an advanced modified graphitic white melon seed shells biochar (Fe/Zn@WBC). The Fe/Zn@WBC demonstrates a substantial enhancement in adsorption efficiency for IMI, achieving a remarkable removal rate of 87.69% within 30 min and a significantly higher initial adsorption rate parameter h = 4.176 mg g-1·min-1. This significant improvement outperforms WBC (12.22%, h = 0.115 mg g-1·min-1) and highlights the influence of optimized adsorption conditions at 900 °C and the graphitization degree resulting from Fe/Zn bimetallic oxide modification. Characterization analysis and batch sorption experiments including kinetics, isotherms, thermodynamics and pH factors illustrate that chemical adsorption is the main type of adsorption mechanism responsible for this superior ability to remove IMI through pore filling, hydrogen bonding, hydrophobic interaction, electrostatics interaction, π-π interactions as well as complexation processes. Furthermore, we demonstrate exceptional stability of Fe/Zn@WBC across a broad pH range (pH = 3-11), co-existing ions presence along with humic acid under various real water conditions while maintaining high removal efficiency. This study presents an advanced biochar adsorbent, Fe/Zn@WBC, with efficient adsorption capacity and easy preparation. Through three regeneration cycles via pyrolysis method, it demonstrates excellent pyrolysis regeneration capabilities with an average removal efficiency of 92.02%. The magnetic properties enable rapid separation facilitated by magnetic analysis. By elucidating the efficacy and mechanistic foundations of Fe/Zn@WBC, this research significantly contributes to the field of environmental remediation by providing a scalable solution for IMI removal and enhancing scientific understanding of bimetallic oxides-hydrophilic organic pollutant interactions.

Green algae Ulva lactuca-derived biochar-sulfur improves the adsorption of methylene blue from water

The present investigation explores the efficacy of green algae Ulva lactuca biochar-sulfur (GABS) modified with H2SO4 and NaHCO3 in adsorbing methylene blue (MB) dye from aqueous solutions. The impact of solution pH, contact duration, GABS dosage, and initial MB dye concentration on the adsorption process are all methodically investigated in this work. To obtain a thorough understanding of the adsorption dynamics, the study makes use of several kinetic models, including pseudo-first order and pseudo-second order models, in addition to isotherm models like Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich. The findings of the study reveal that the adsorption capacity at equilibrium (qe) reaches 303.78 mg/g for a GABS dose of 0.5 g/L and an initial MB dye concentration of 200 mg/L. Notably, the Langmuir isotherm model consistently fits the experimental data across different GABS doses, suggesting homogeneous adsorption onto a monolayer surface. The potential of GABS as an efficient adsorbent for the extraction of MB dye from aqueous solutions is highlighted by this discovery. The study's use of kinetic and isotherm models provides a robust framework for understanding the intricacies of MB adsorption onto GABS. By elucidating the impact of various variables on the adsorption process, the research contributes valuable insights that can inform the design of efficient wastewater treatment solutions. The comprehensive analysis presented in this study serves as a solid foundation for further research and development in the field of adsorption-based water treatment technologies.

Adsorption of direct blue 106 dye using zinc oxide nanoparticles prepared via green synthesis technique

Zinc oxide nanoparticles (ZnO-NPs) have in recent times shown effective adsorption capability for the confiscation of colour contaminants from aqueous environments (aquatic ecosystems or water bodies) due to the fact that ZnO contains more functional groups. Direct blue 106 (DB106) dye was selected for this present study as a model composite due to its wide range of uses in textiles (cotton and wools), woods, and paper industries, as well as their therapeutic applications, along with its potential for impairments. This study therefore focuses on the use of DB106 dye as a model composite due to its wide range of uses in textiles (cotton and wools), woods, and paper industries, as well as their therapeutic applications and their potential for impairments. Furthermore, the surface functionalization, shape, and composite pore size were revealed by TEM, FTIR, UV, and BET techniques. The current study uses green synthesis method to prepare ZnO-NPs as an adsorbent for the DB106 dye molecules adsorption under various conditions using the batch adsorption process. The adsorption of DB106 dye to the ZnO-NPs biosorbent was detected to be pH-dependent, with optimal adsorption of DB106 (anionic) dye particles observed at pH 7. DB106 dye adsorption to the synthesized ZnO-NPs adsorbent was distinct by means of the linearized Langmuir (LNR) and pseudo-second-order (SO) models, with an estimated maximum adsorption capacity (Q_m) of 370.37 mg/g.