A Large-scale Preparation Of Cellulose Based Adsorbent And Its Application

With the rapid development of industrial society, the heavy metal pollution has been seriousdue to human’s frequent activities of heavy metals mining, smelting, processing and commercialmanufacturing. It is a threat to safe drinking water and human health that the heavy metalwastewater was discharged into environment directly. therefore, it’s of great necessary fortreatment of heavy metal pollution. Until now, the methods used in heavy metal wastewatertreatment are precipitation, redox, ion exchange, solvent extraction, electrolysis et al. Most ofthese control methods have issues of high operating costs, operational complexity, secondarypollution et al, however, adsorption method has been favored by many researchers for its lowcost, easy operation and so on. Seeking a kind of cheap eco-adsorbent with high efficiency ofheavy metal adsorption which is easily prepared and can be used in industrial production, hashigh ecological and economic value.On the basis of preliminary studies, the paper directly use the crushed waste mulberrybranches as a raw material, acrylic acid (AA) and acrylamide (AM) as monomers, ammoniumpersulfate (APS) as initiator, N, N-methylenebisacrylamide acrylamide (MBA) as a crosslinkingagent, graft synthesis of a series of cellulose based adsorbent material with a porous structure via50times magnification process，and used for separation and recovery of heavy metal ions inwater environment. Single factor experiment is used to explore the optimal preparationconditions of adsorbent material under the measurable indicator of absorbency, optimizinglarge-scale preparation technical of cellulose based adsorption material, Regulation of itscomponents, Structure, surface and interface physical and chemical properties. To explore thecellulose-based adsorbent potential for practical application, systematic study of cellulose-basedadsorbent material components, as well as pH, temperature, time, initial concentration of heavymetal ions and other environmental factors on the adsorption effect of Cr (Ⅲ), Cu (Ⅱ), Co (Ⅱ)three kinds of heavy metal ions, besides, the competitive adsorption property of metal ions andthe regeneration performance of the sample were also studied. The results are shown asfollowing:1. The large scale preparation of cellulose based adsorption material and its performance studyOn the basis of the previous studies, implementation an enlarged production of celluloseadsorption material by50times. The synthetic conditions were optimized as follow: MBP50g, the mass ratio of MBP/AA/AM is1.2/3.8/1, reaction temperature70℃, initiator4.0g,crosslinking agent1.5g. The resultant cellulose-based absorbent materials obtained adsorptioncapacity of655.9g/g,247.4g/g,63.1g/g under45℃in deionized water, tap water,0.9wt%NaCl solution respectively. Water absorption ratio of the sample was83%of the first cycle aftereight cycles of adsorption-desorption, indicating an excellent capacity of repeat waterabsorption. The water retention capacity of samples can reach90.5%and63.7%at thetemperature of25℃and40℃respectively，when the pressure is30Kpa, the water retentioncapacity of about80%, indicating that the sample has good water retention capacity; Degradationexperiment shows an perfect biodegradability of cellulose based adsorbent.2. The study of adsorption behavior of cellulose-based materials for heavy metal ions.TheBy the study of the effect of sample dosage, ion initial concentration, PH, temperature andother factors on the adsorption properties, explore the competitive adsorption of metal ions andrecycling performance of materials, it can be concluded that the heavy metal uptake capacity ofmaterial increased with the increase of solution pH, resulting from the decrease of electrostaticrejection at high pH. Temperature had no significant effect on the adsorption behavior of metalions and the metal ions uptake capacity of sample in the order of Cu(Ⅱ)＞Cr(Ⅲ)＞Co(Ⅱ).Metal ion adsorption process in line with the pseudo-second-order kinetic model, indicating thatthe adsorption of metal ions in the sample belongs to the chemical adsorption; adsorptionisotherm in line with Langmuir equation, indicating that the sample has a uniform surface andadsorption energy. The priority order in multi-component adsorption was Cr(Ⅲ)＞Cu(Ⅱ)＞Co(Ⅱ). The metal ion uptake capacity of the sample for Cu(Ⅱ) was83%of the first cycle aftersix cycles of adsorption-desorption, indicating an excellent reusability of sample.In this paper, based on previous studies, achieve50times the cellulose-based absorbentmaterial enlarge production, with realistic reference value for the subsequent industrialproduction. Agricultural waste resources as raw materials to produce environmentally friendlyabsorbent material and successfully applied to the removal of heavy metal ions in aqueoussolution, it open up new ways to prevent water pollution via combining the removal of heavymetal ions in aqueous solution and resource conservation management two hot spots, form a newcleaner production technology and conducive to the development of recycling economy.