Biochemistry & Physiology: Open Access
Open Access

Gold nanospheres; Gold nanorods; Dimethoate; Adsorption; Organophosphate pesticide; Environmental remediation

Introduction

Organophosphate pesticides are widely used in agricultural practices to control pests and increase crop yields. However, their extensive use has led to serious environmental concerns due to their persistence, toxicity, and potential bioaccumulation. Among these pesticides, dimethoate has been identified as a hazardous compound with adverse effects on aquatic ecosystems and human health. Therefore, developing effective strategies to remove dimethoate from contaminated water sources is crucial.

The change in dielectric constant of silver upon pesticide binding which is less compared to that of gold gives the gold advantage over silver or some cheaper metal nanomaterials. Nair and Pradeep supported gold nanoparticles on alumina and made online water filter to demonstrate technology of OPs removal from water in rural communities in India [1]. Moreover, water purification from an environmental perspective by using gold-poly nanocomposite in the form of a foam was described.

Rod-shape nanoparticles possess several advantages over the nanospheres, such as high surface area and good electron mediation capability. However, to date, to the best of our knowledge the use of gold nanorods for adsorption of OP dimethoate has not been reported [2]. In this contribution, we considered gold nanoparticles of two different shapes nanospheres and nanorods as adsorbents of dimethoate from aqueous solutions. The aim of our study was to characterize the interaction between dimethoate and gold nanorods. NSs and NRs have different physical and chemical properties, so the effects of these properties on their performance as adsorbents are discussed. We have also compared direct uses of investigated NPs for removal of dimethoate from drinking water [3].

Gold nanoparticles have gained significant attention in recent years due to their unique physicochemical properties and potential applications in various fields. Their high surface area, stability, and tunable surface properties make them promising candidates for pollutant adsorption. In this study, we explore the adsorption behavior of dimethoate onto gold nanospheres and nanorods and evaluate their efficacy as adsorbents for pesticide removal.

Gold nanospheres and nanorods were synthesized using wellestablished methods, and their structural and morphological properties were characterized using transmission electron microscopy and UVVis spectroscopy [4]. The adsorption experiments were conducted by adding known concentrations of dimethoate to solutions containing the AuNPs, and the adsorption kinetics and isotherms were studied.

The characterization results confirmed the successful synthesis of gold nanospheres and nanorods with distinct shapes and sizes. The UVVis spectra exhibited characteristic surface plasmon resonance peaks for each nanoparticle type, validating their synthesis. The adsorption experiments revealed that both gold nanospheres and nanorods exhibited significant adsorption capacities for dimethoate. The kinetics of adsorption followed a pseudo-second-order model, suggesting a chemisorption mechanism. Furthermore, the adsorption isotherms followed the Langmuir model, indicating monolayer adsorption [5].

Discussion

The adsorption of organophosphate pesticide dimethoate on gold nanospheres and nanorods has shown promising results in this study. The discussion section aims to provide a deeper understanding of the findings and highlight their significance.

The high adsorption capacity observed for both gold nanospheres and nanorods suggests that they are effective adsorbents for dimethoate removal from aqueous solutions. The large surface area of gold nanoparticles, combined with their unique surface properties, plays a crucial role in facilitating the adsorption process. The presence of thiol groups on the nanoparticle surface promotes strong interactions with the pesticide molecules, leading to efficient adsorption [6].

The kinetics of adsorption followed a pseudo-second-order model, indicating a chemisorption mechanism. This suggests that the adsorption process involves chemical bonding between the pesticide molecules and the gold nanoparticles’ surface. The chemisorption mechanism implies a more stable and irreversible adsorption, which is desirable for effective pesticide removal [7].The adsorption isotherms exhibited behavior consistent with the Langmuir model, indicating monolayer adsorption. The Langmuir model assumes a homogeneous adsorbent surface and assumes that adsorption occurs on a single layer of adsorbate molecules. The monolayer adsorption implies that the maximum adsorption capacity of the gold nanoparticles for dimethoate has been reached.

The unique geometry of gold nanorods may provide additional advantages for adsorption compared to nanospheres. The elongated shape of nanorods offers an increased contact area and improved accessibility for the pesticide molecules. This enhanced surface-tovolume ratio can contribute to higher adsorption capacities and potentially faster adsorption kinetics [8].

The findings of this study have important implications for the development of gold nanoparticle-based adsorbents for pesticide remediation. Gold nanoparticles have demonstrated their potential as efficient adsorbents for removing dimethoate from water sources. Further research can focus on optimizing the synthesis parameters of gold nanoparticles to enhance their adsorption capacities and improve their stability in various environmental conditions.

Additionally, it would be valuable to explore the regeneration potential of the adsorbents. Understanding whether the gold nanoparticles can be regenerated and reused after adsorbing pesticides would contribute to their practical application and cost-effectiveness [9].

While this study provides valuable insights into the interaction between gold nanoparticles and dimethoate, it is essential to consider the real-world conditions and potential interferences that may affect the adsorption process. Further studies should evaluate the performance of gold nanoparticle-based adsorbents in complex water matrices and assess their long-term stability and efficiency.

The high adsorption capacity of gold nanospheres and nanorods for dimethoate can be attributed to their large surface area and surface properties. The presence of thiol groups on the surface of AuNPs facilitates the formation of strong interactions with the pesticide molecules, leading to effective adsorption. Additionally, the unique geometry of nanorods may enhance the adsorption efficiency due to increased contact area and improved accessibility [10].

Conclusion

This study demonstrates the potential of gold nanospheres and nanorods as efficient adsorbents for the removal of the organophosphate pesticide dimethoate from aqueous solutions. The results indicate that the adsorption process follows a chemisorption mechanism and can be described by the Langmuir isotherm model. The findings pave the way for further research on the development of gold nanoparticle-based adsorbents for pesticide remediation and provide valuable insights into the interaction between nanomaterials and pesticide contaminants. Future studies can focus on optimizing the synthesis parameters, exploring the regeneration potential of the adsorbents, and assessing their performance under real-world conditions.

Conflict of Interest

None

Acknowledgement

None

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