Water contamination by heavy metals, cyanides and dyes is increasing globally and needs to be addressed as this will lead to water scarcity as well as water quality. Different techniques have been used to clean and renew water for human consumption and agricultural purposes but they each have limitations. Among those techniques, membrane technology is promising to solve the issues. Nanotechnology present a great potential in wastewater treatment to improve treatment efficiency of wastewater treatment plants. In addition, nanotechnology supplement water supply through safe use of modern water sources. This chapter reviews recent development in membrane technology for wastewater treatment. Different types of membrane technologies, their properties, mechanisms advantages, limitations and promising solutions have been discussed.

In this study, a simple, rapid and effective in-syringe micro-solid phase extraction (MSPE) method was developed for the separation and preconcetration of parabens (methyl, ethyl, propyl and butyl paraben) in environmental water samples. The parabens were determined and quantified using high performance liquid chromatography and a photo diode array detector (HPLC-PDA). Chitosan-coated activated carbon (CAC) was used as the sorbent in the in-syringe MSPE device. A response surface methodology based on central composite design was used for the optimization of factors (eluent solvent type, eluent volume, number of elution cycles, sample volume, sample pH) affecting the extraction efficiency of the preconcentration procedure. The adsorbent used displayed excellent absorption performance and the adsorption capacity ranged from 227–256 mg g⁻¹. Under the optimal conditions the dynamic linear ranges for the parabens were between 0.04 and 380 µg L⁻¹. The limits of detection and quantification ranged from 6–15 ng L⁻¹ and 20–50 ng L⁻¹, respectively. The intraday (repeatability) and interday (reproducibility) precisions expressed as relative standard deviations (%RSD) were below 5%. Furthermore, the in-syringe MSPE/HPLC procedure was validated using spiked wastewater and tap water samples and the recoveries ranged between from 96.7 to 107%. In conclusion, CAC based in-syringe MSPE method demonstrated great potential for preconcentration of parabens in complex environmental water.