Excellent acid resistance and MXene enhanced photothermal conversion of bilayered porous solar evaporator fabricated by palygorskite and pectin.

Acidic wastewater comes from a wide range of sources in industrial process. The traditional treatment method of acidic wastewater is acid-base neutralization which consumes a lot of chemicals. In recent years, much attention has been paid to the treatment of wastewater through solar interfacial evaporation. However, many of the reported evaporators present challenges in terms of poor acid resistance and costly raw materials. In this article, the three-dimensional porous MXene/PPAL aerogel was prepared by directional freeze-drying using inexpensive Palygorskite (Pal) and renewable pectin, then a moderate amount of MXene was sprayed onto the aerogel surface to create a double-layer solar evaporator. The prepared evaporator exhibited great mechanical properties with a compressive strength of 0.85 MPa at 70 % strain, and high vapor rate of 1.5474 kg m−2 h−1 that equals 94.7 % photothermal conversion efficiency. Furthermore, photothermal conversion efficiency of the solar evaporator in 5 % H 2 SO 4 solution (p H = 1) was 90.2 %, which was only slightly different from that in pure water. The results provided a new technology that easy recovery of acidic wastewater and reused treated water from industrial acidic wastewater through economical and efficient solar interfacial evaporation. [Display omitted] • MXene-PPAL has advantages of low cost, simple and scalable manufacture process. • MXene-PPAL shows excellent energy conversion efficiency of 94.7 % under 1 sun irradiation. • MXene-PPAL shows excellent acid resistance with a high energy conversion efficiency of 90.2 % obtained even in 5 wt% H 2 SO 4 under 1 sun irradiation. [ABSTRACT FROM AUTHOR]