Robust, sustainable cellulose composite aerogels with outstanding flame retardancy and thermal insulation.

Robust and sustainable cellulose composite aerogels were prepared by incorporating MgAl-layered double hydroxide (MgAl-LDH) as green nanofillers and flame retardants. Two series of aerogels combining MgAl-CO3 LDH (MA-C) and MgAl-H2PO4 LDH (MA-P) were achieved, in which both MA-C and MA-P were uniformly dispersed in cellulose substances. The cellulose composite aerogels with 1.8 wt% of MA-C (denoted as CAC) and MA-P (denoted as CAP) displayed excellent mechanical properties, increased by 2.6 and 2.8 times compared with neat cellulose aerogels (CA), respectively. The peak of heat release rate (PHRR) of CAC and CAP reduced by 41 % and 50 % compared with the neat one, respectively, demonstrating the outstanding flame retardancy. The reduction in smoke production ratio (SPR) was 79 % for CAC and 75 % for CAP, respectively, indicating enhanced smoke suppression performance. Therefore, the high performance flame-retardant cellulose composite aerogels exhibit an application prospect in green advanced engineering field.

Highly efficient adsorption and recycle of phosphate from wastewater using flower-like layered double oxides and their potential as synergistic flame retardants.

Here, a novel Mg/Al-layered double oxide (MgAl-LDO) with a flower-like architecture was synthesized through facile green co-precipitation and calcination methods for phosphate separation and recycle from wastewater. The as-prepared MgAl-LDO demonstrated high specific surface area of 200.17 m2/g based on its 3D hierarchical flower-like structure. The phosphate adsorption was well conformed to Pseudo-second-order kinetic model and Langmuir model, suggesting a homogeneous monolayer chemisorption with a maximum adsorption capability of 103.61 mg P/g. The existence of Cl-, NO3- ions did not interfere with phosphate adsorption, while high concentration SO42- and CO32- affected the phosphate adsorption. In addition, adsorption mechanism analysis revealed that high-efficiency phosphate capture by MgAl-LDO was mainly due to the electrostatic adsorption, surface inner-sphere complexation, ligand exchange and precipitation combined process. Remarkably, the phosphate adsorbed MgAl-LDO (P-LDO) can be employed as synergistic flame retardant to improve the flame retardancy of paper.