3-mercaptopropyltrimethoxysilane-Modified Multi-walled Carbon Nanotubes as a New Functional Adsorbent for Flow Injection Extraction of Pb(II) from Water and Sediment Samples

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)In the present study, a novel synthesized adsorbent material based on 3-mercaptopropyltrimethoxysilane-functionalized multi-walled carbon nanotubes was used to increase the Pb2+ adsorption from aqueous solutions in a flow injection solid-phase extraction system coupled to flame atomic absorption spectrometry. Spectroscopic and microscopic techniques (Fourier transform infrared spectroscopy, energy dispersive spectroscopy, and scanning electronmicroscopy) were employed to confirm the chemical modification of the adsorbent surface. Preconcentration conditions (sample pH, flow rate, buffer solution, and eluent concentrations) were optimized using factorial and Doehlert matrix designs that made it possible to construct a linear graph in the 5.0- to 130.0-mu gL(-1) range (r=0.9999) and estimate detection and quantification limits (1.7 and 5.7 mu gL(-1), respectively). The method precision was found to be 4.20 and 1.97% for 5.0 and 100.0 mu gL(-1) Pb2+ solutions, respectively. When using the 3-mercaptopropyltrimethoxysilane-functionalized multi-walled carbon nanotubes, the sensitivity for the Pb2+ trace determination was improved to 95 % compared with the oxidized multi-walled carbon nanotubes, thus evidencing the significant enhancement of the adsorption capacity. The developed method was successfully applied to the analysis of Pb2+ species in different water samples and the PACS-2 marine sediment-certified reference material.223960696081Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Instituto Nacional de Ciencia e Tecnologia de Bioanalitica (INCT)Fundacao Araucaria do ParanaFAEPE-UELConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Adsorption

Removing of wastewater pollutants by novel adsorption techniques is urgent as they are continuously defiling the limited freshwater resources, seriously affecting the terrestrial, ecosystems, aquatic, and aerial flora and fauna. Emerging carbon nanotube (CNT)-based adsorbent materials are effective for efficient handling of wastewater pollutants. This chapter describes the mechanisms of CNT, and its forces to host the wastewater pollutants. Such details would help to considerably improve the performance of classical adsorbent technologies. Additionally, the functionalization of CNT and adsorption isotherms are considered as they have been significantly used for achieving maximum adsorption capacity and disclosing the adsorption phenomena of CNT, respectively. Some multifunctional CNT-based adsorbent are also discussed with reusability phenomena which need to be addressed before large-scale implementation of CNTs for water purification. Some suggestions and research clues are given to inform investigators of potentially disruptive CNT technologies and/or optimize the CNT sorption performances that have to be investigated in more detail