Fabrication of green poly (L‐lactic acid) hybrid membrane through incorporation of functionalized natural halloysite nanotubes

Abstract

BACKGROUND Membrane technology has attracted increasing interest in the field of separation and purification. Unfortunately, conventional membrane materials are usually derived from non‐renewable fossil resources that are difficult to degrade at the end of their life. In this work, as a sustainable alternative to the conventional polymer membrane, the biobased ploy (L‐lactic acid) (PLLA) hybrid membrane was successfully fabricated through the incorporation of modified natural halloysite nanotubes (HNTs). RESULTS The PLLA/HNT hybrid membranes were analysed by attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and contact angle measurement. The pure water flux of the hybrid membrane increased from 140.3 to 329.7 L.m−3.h−1, while the bovine serum albumin (BSA) rejection ratio decreased from 94.3 to 82.7% with increasing HNT loading content from 0 to 1 wt%. Moreover, the addition of HNTs could also enhance the antifouling performance of the hybrid membrane. CONCLUSION The green PLLA/HNT hybrid membrane was successfully made from the recoverable and biodegradable PLLA and naturally occurring HNTs. Compared with the PLLA‐based membranes reported in the literature, the PLLA/HNT hybrid membranes presented relatively high permeability, moderate BSA rejection, and good antifouling performance. The green poly (L‐lactic acid) hybrid membranes hold great promise for practical application as they can contribute to a circular economy and sustainable development. © 2022 Society of Chemical Industry (SCI).

Development of Mixed-Dimensional Membranes Comprising Halloysite Nanotubes and Kevlar Aramid Nanofiber for Enhanced Small-Molecule Dye/Salt Separation

“…This may be attributed to the fact that HNTs contain a high number of hydrophilic groups −OH, which improves the hydrophilicity of the mixed-dimensional membrane and helps water pass through the membrane. This is in good agreement with the test measurements of the contact angle test. , The flux decreases when the content of HNTs increases to 35%. This is mainly because when the HNTs content is high, HNTs will agglomerate in the membrane and it is difficult to disperse evenly, increasing the transmission resistance of water and reducing the flux.…”

“…The rough membrane surface leads to the increase of its effective filtration area, accompanied by the large number of hydrophilic groups of HNTs. Therefore, the mixed-dimensional membrane of HNTs/KANF increased the hydrophilicity and improved the permeability. , …”

“…The water contact angle decreased from 75.3° of the 0% HNTs/KANF membrane to 73.4, 71.6, 70.3, and 67.5° with the increasing HNTs loading in the KANF, indicating that the HNTs increased the hydrophilicity of the membrane. This may be because the natural hydrophilic functional groups (such as −OH) introduced by HNTs enhanced the surface hydrophilicity of the membrane. , The zeta potential of the membranes and HNTs powder was tested to study the charge characteristics of the membrane surface. When pH = 7, the zeta potential of HNTs powder is about −34.6 mV.…”

“…This is mainly related to the hydrophilicity of HNTs. HNTs exist more on the membrane surface, which is more conducive to the role of HNTs …”

Enhanced mechanical and tribological properties of epoxy‐based coatings by in‐situ synthesized silicon dioxide nanoparticles

“…In addition, the peak intensity gradually weakens along with the increase of the inorganic content, which resulted from the disorder of the epoxy molecular chain 37,38 . As shown in the FTIR spectra (Figure 2b), the characteristic absorption peaks of the epoxy resin appeared at 827 and 1225 cm −1 corresponding to COC bonds 39 . Besides, the in‐situ synthesized nanoparticles show the characteristic peaks of SiO bonds at 1036 cm −1 , and the broad peak at 3310–3470 cm −1 should be caused by NH 2 and OH.…”