Biomass material derived hierarchical porous TiO2: Adjustable pore size for protein adsorption

In this paper, a simple and reproducible approach combining biomass materials Acacia mangium tannin extract (BA tannin) and triblock copolymer pluronic (P123) as dual template was first presented to synthesize hierarchically porous TiO2. Nontoxic and low-cost titanium sulfate (Ti(SO4)2) replaced conventional poisonous and costly organic alkoxide. Attractively, biomass materials BA tannin processed sulfonic group and phenolic hydroxyl group, which played an important role to act as coordinating ligands to control hydrolysis rate of metal salt. Thermogravimetric (TG) analysis was used to evaluate the calcination temperature and X-ray photoelectron spectra (XPS), X-ray powder diffraction (XRD), nitrogen sorption isotherms, mercury intrusion porosimetry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the chemical composition, crystalline structure and pore architecture features of TiO2. The results showed that TiO2 possessed multiscale porous structure with macropore of about 4 μm and mesopore of about 13 nm, and the pore structure can be adjusted by varying the ratio of P123 and BA tannin. Batch adsorption experiment exhibited the satisfied adsorption capacity of 42 mg/g for lysozyme (Lyz). And the real application of TiO2 was also tested using leather softening wastewater, which indicated that dual-templated TiO2 with hierarchical porosity was a good candidate for use as an adsorbent for biomacromolecule in wastewater treatment. [Display omitted] •A simple, low-cost, environmental and reproducible approach was first reported using biomass material BA tannin and triblock copolymer pluronic P123 as dual template to synthesize hierarchical porous TiO2.•Varying the ratio of P123 and BA tannin played an important roles in the synthesis of hierarchical porous TiO2 with adjustable pore diameter.•TiO2 material with hierarchical porosity showed superior adsorption capacity of proteins compared with single porosity structure.