The Study Of Characteristics And Oil Absorption Of Chemically Modified Corn Stalks

With urbanization and industrial development, the world is confronted with a widevariety of impacts from petroleum products and their derivatives. During extraction, refining,transfer, storage and especially transportation on the open seas, large quantities of petroleumpollutants are produced and released into the aquatic environment, which affects the oceanecology and the natural environment seriously.In order to minimize the pollution, primary task is to prevent the spread of oil from largeareas of contamination. Then various integrated strategies should be adopted to keep the riskfrom becoming an ecological disaster, and reduce the social, environmental and economicimpact from oil pollutions. Generally, conventional techniques for oil spill pollution includemechanical extraction, chemical dispersants, in situ burning, and bioremediation. Mechanicalextraction by Sorbents seems to be the most economical and efficient countermeasures in oilspill cleanup. Oil sorbent materials are able to concentrate and transform oil contaminantsfrom liquid into solid or semi-solid phase, which becomes much easier to handle in aconvenient manner without significant oil draining out.In the present study, corn stalks were used as oil sorbent materiel. They were abundantagricultural by-products, and widely distributed throughout the world. Corn stalks have manyadvantages, such as low density and cost, non-toxicity and biodegradation with faint fragrance.So it can be used as oil sorbent materials to enlarge their scope of application and raise theutilization rate of resources. However, unmodified raw agricultural waste has a low oiladsorption capacity and variable physical stability. Therefore, modification should be carriedout to boost its performance.In this study, powdered raw corn stalk (RCS) was modified with styrene, Butylmethacrylate and styreneby means of suspension polymerization, to obtain two new crude oilabsorption materials, styrene grafted corn stalks (SCS) and Butyl methacrylate and styrenegrafted corn stalks (BMS-CS). Then the performanceof raw corn stalks (RCS), SCS andBMS-CS as potential sorbent materials for oil removal in pure oil medium and oil/watermedium were investigated. Some factors，such asparticle size, contact time, adsorptiontemperature, oil retention and reusability were also determined to evaluate the most suitableadsorption condition. The physico-chemical structure of RCS, SCS and BMS-CS wasperformed by Scanning Electron Microscopy, Fourier transform infrared spectroscopy, X-raydiffraction analysis, respectively. The following conclusions were obtained.1) The optimum conditionsfor SCS was as follows: the quality of RCS, initiator ammonium BPO, monomer styrene, cross-linked agent MBA were3.00g,0.30g,12.0mL,0.02g, respectively; and the reaction was conducted simultaneously at60°C for6h. Theoptimum conditions determined by orthogonal experiment for BMS-CS were as follows:concentrations of initiator ammonium ceric nitrate, monomer n-butyl methacrylate andstyrene were2.0mmol/L,0.6mol/L and0.012mol/L, respectively; the dosage of cross-linkedagent N, N’-methylene-bis-acrylamide was0.1%(relative to the quality of RCS); and thereaction was conducted simultaneously at50°C for25h.2) SEM analysis showed that SCS and BMS-CS were corroded and became rougher thanRCS. The increase of roughness was also convinced by the decline in crystallinity. Newlyemerging absorption peaks in FT-IR spectra indicated that hydrophobic groups had beengrafted to the surface of RCS. Based on the results of FT-IR, SEM and XRD analyses, rawcorn stalk (RCS) was successfully grafted withstyrene, BMA and styrene. Both of themenhanced oil absorption capacity of modified material. Additionally, the cellulose structurewas not destroyed apparently after modification. This can be beneficial to the subsequenttreatment.3) Performance measurement showed that at room temperature oil absorption capacitiesof RCS and BMS-CS were5.23g/g,16.73g/g, and20.12g/g, respectively. It was obviousthat the latter was higher than the former. The absorption experiment exhibited that SCS andBMS-CShad rapid oil sorption equilibrium. Sorption capacity decreased significantly with theincreaseof temperature while it depended only slightly on particle size. Additionally, theabsorbed oil could be removed from sorbentby a simple mechanical press, and SCS andBMS-CS could be reused. Therefore, they exhibited good oil sorption properties, rapid oilsorption equilibrium, excellent oil/waters electivity, high oil retention and re-usability. Inshort, the above investigation indicated that RCS and BMS-CS were possible to be used asanattractive natural materials since being cellulosic or protein based, it was cheap, innocuousand biodegradable except for the former advantages.