The Effect Of Iron-Manganese-Silicon On The Biomass Composition Of Eichhornia Crassipes

Eichhornia crassipes (i.e. water hyacinth) has been listed as one of the world's top ten harmful weeds, due to its strong reproductive capacity. In recent decades, many scholars have tended to use water hyacinth, in control and utilization of water hyacinth. Water hyacinth has a strong water purification function, accumulation ability for heavy metals, and its post-harvest biomass is also a potentially excellent adsorbent, but the role of metal ions in vivo is not clear. To investigate the role of iron, manganese and silicon in water hyacinth biomass, the paper studies the distribution of iron, manganese and silicon, and their influence on Cu, Mg, P, and K in water hyacinth. And FT-IR, XRD, SEM-EDX were used to characterize its functional group abundance, crystallinity, and the element distribution in the plant materials. The main results are as follows:(1) Except for Mn, FeSi, FeMnSi treatments, the sequence of Fe content in the three parts of plant is root> leaf> stem; the sequence of manganese content in the different parts of plant (except for Si and Fe treatments) is root> stem> leaf; the order of silicon content in the three parts of plant (except for Mn treatment) is root> stem> leaf. Silicon in plant benefited iron to accumulate in the roots, but less iron transfer to the stems and leaves. Manganese increased iron allocation to leaves, in order to facilitate photosynthesis when iron deficiency. Iron can reduce the content of manganese in plant, silicon increases the content of manganese and manganese help absorption of silicon in the water hyacinth root. High concentration of iron inhibits the absorption of high concentration manganese in water hyacinth and promotes the water hyacinth's absorption of low concentration manganese, but inhibits manganese accumulation in roots. The different distribution of iron, manganese, silicon in the water hyacinth will be affected to some extent of water hyacinth biomass material features.(2) Low concentration iron favors magnesium accumulation in water hyacinth roots, inhibits the absorption of Cu in plant. High concentration iron avail the absorption of Cu in stems and leaves. Low concentration iron inhibits the absorption of P in water hyacinth, but high concentration iron enhances the absorption of P, especially in roots. Iron can significantly promote the absorption of water hyacinth on K, but with the increase of the concentration of iron, iron inhibits the absorption of water hyacinth on K. Manganese promotes the magnesium accumulation in plant root, inhibit the accumulation of magnesium in stems and leaves. Mn inhibits the absorption of Cu in plant roots. Low concentration manganese inhibits the accumulation of P in water hyacinth stems and leaves, favors plant root uptake of phosphorus, but high conconcentration manganese inhibits plant uptake of phosphorus. Silicon favors the absorption of magnesium in water hyacinth root and inhibits the accumulation of magnesium in stems and leaves. Silicon favors the absorption of magnesium in water hyacinth root and inhibits the accumulation of magnesium in stems and leaves. To the contrary, silicon inhibits the absorption of Cu in water hyacinth root and favors the accumulation of Cu in stems and leaves. Silicon is no significant effect on P absorption in water hyacinth roots, but inhibits the accumulation in stems and leaves. Silicon inhibits the uptake of K. The effect of iron, manganese and silicon in the water hyacinth affect Mg, Cu, P, K distribution for water hyacinth biomass material the formation needs further study.(3) The rules of adsorption sites in water hyacinth are:the sequence of acidic sites amount among the three parts of plant is root> stem> leaf, in the treatment of Fe, Mn and their combination, and leaf> stem> root in Si treatment. Mn and Si can enhance acidic sites of the plant, in which Mn plays a great role, but Fe reduces the acidic sites. Fe reduces the alkaline sites in leaves and enhances the alkaline sites in root and stem of water hyacinth. Mn promotes the alkaline sites in roots and reduces alkaline sites in stems and leaves. Si reduces the alkaline sites in water hyacinth roots and leaves and promotes stems to produce more alkaline sites. High concentration Mn for water hyacinth produces more alkaline sites and high concentration iron for plant produces more alkaline sites in stems and leaves. This shows that different concentrations of iron, manganese, silicon in water environment can change some extent of characteristics of charge, thus changing the nature of the water hyacinth biomass.(4) FT-IR spectra show that:Mn and Si treated stalks of water hyacinth have more amorphous material, such as lignin, pectin and xylan (hemicellulose), which have more C=C,-CH2,-C-O,-OH,-COOH and acidic sites. Fe increases-CH3 functional group, which can reduce adsorption sites, is not conducive to the chemical modification of biomass materials..(5) X-ray diffraction pattern shows that:the cellulose of roots and leaves of water hyacinth has low crystallinity; silicon and iron can enhance the crystallinity in roots, manganese reduces cellulose crystallinity of the roots. Iron and manganese can reduce the cellulose crystallinity of plant stems and leaves. High concentration iron can increase the cellulose crystallity of plants, especially of plant roots. Manganese reduces cellulose crystallinity of the plant. Fe, Mn and Si has the same contribution on the crystallization of water hyacinth biomass and their functional groups.(6) SEM-EDX analysis shows that:C, O, Si, P and Na is the composition of cell wall elements, and mainly in the plant cell wall, Ca and S is more evenly distributed. High concentration of iron and manganese makes the plant cell wall and the root surface distribution Fe and Mn, also enhance the level of P, Al absorption. Different elements distribution in plant tissues is caused by nutritional conditions of Fe, Mn, Si, and has ralation with biomass structure and adsorption characteristics.