Resource-efficient pre-treatment with partial desalination approach using graphene-MXene coated cellulose filters for desalination plants

The impact of the water crisis is significant, and among the available solutions, the desalination of seawater and brackish water stands out. Herein, a simple, energy-efficient, and scalable, dual-functional method for pretreatment followed by partial desalination of seawater is reported. A hybrid filtration setup was employed, consisting of naturally available, environmentally friendly adsorbents such as fine sand, carbon, and cellulose filters coated with graphene oxide (GO) and Ti₃C₂T _<i>x</i> MXene. These materials are arranged in layers forming a sandwich structure, allowing seawater to pass through naturally by gravity, without external pressure, making the system highly energy-efficient. The lab-made hybrid filter can process up to ∼2 L of water per hour using a small effective filtration area of ∼63 cm². The influence of coating concentration was studied using four different concentrations, where 1 mg mL^-1 coatings showed better performance for both GO and MXene. After filtration, the water was analysed using various quality parameters, and the filter components were examined <i>via</i> FESEM with EDS to assess morphology and elemental composition. Among GO and MXene, GO-coated filters performed better, achieving a satisfactory pretreatment and a 17.7% reduction in salinity without any external energy input. The salt rejection is mainly attributed to adsorption and electrostatic interactions between the coated materials and dissolved ions in seawater.