Praperation Of Hydrogen Manganese Oxide/Cellulose Composite Film And Its Adsorption Performance On Lithium Ions

Seawater contains a large amount of lithium resources(the world's oceans contain about 2.6×1011 tons of lithium,an amount four orders of magnitude larger than the lithium reserves on land)awaiting development.The spinel-structured hydrogen manganese oxide(HMO)is an effective material for lithium adsorption,but its powder form limits its application in seawater lithium recovery.Here,a simple and environmentally friendly method was used to prepare a renewable and recyclable HMO/cellulose film(natural polymer cellulose as raw material and HMO as Li+adsorption particles)and use it to extract lithium ions from a lithium-containing aqueous The lithium adsorption performance of the composite membrane prepared under different conditions(HMO loading,cellulose concentration,membrane thickness,etc.)were studied by static adsorption experiments.Combined with adsorption kinetics model,adsorption isotherm model,the adsorption behavior of adsorbent was explored.At the same time,adsorption selectivity,desorption and cyclic regeneration of adsorbent were investigated.The efficiency of Li+extraction from seawater(ppb level)and its selectivity to Li+were studied.The hydrophilic and porous cellulose matrix film provided good accessibility to the Li+adsorption sites of HMO,as indicated by the minimal loss of Li+adsorption capacity of HMO/cellulose film as compared to HMO particle alone.The 50%-HMO/cellulose film exhibited a higher Li+adsorption capacity(21.6 mg g-1 HMO)than HMO/polymer(e.g.,polyvinyl chloride or polyacrylonitrile)films,which have been examined in the literature for Li+extraction.All tested adsorbents followed Langmuir-type and pseudo-second-order model Li+ adsorption.The kinetics analysis based on a pseudo-second-order model indicated that the Li+extraction rate of the HMO/cellulose film was three times higher than that achieved by the HMO particle alone(i.e.,0.075 cf 0.023 g mg-1 h-1).In the multi-salt solution,the HMO/cellulose film showed selective Li+adsorption;In addition,the adsorption capacity and mechanical strength of the HMO/cellulose film remained stable even after eight adsorption-desorption cycles.Furthermore,the HMO/cellulose film displayed high selectivity for Li+when exposed to seawater-the extraction of Li+reached 99%,whereas that of the other ions present in seawater(i.e.,Sr2+,K+,Ca2+)was less than 4%.In the cyclic adsorption experiment,the adsorption capacity of the HMO/cellulose film remained stable,Li+adsorbed on the film could be eluted with 0.5 mol L-1 HCl,and the desorption efficiency could reach more than 99%.The present findings demonstrate the potential of the present HMO/cellulose film for the recovery of Li+from seawater or waste water.