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1.

Purpose

The production of technosols to remediate polluted or sealed urban soils to sustain new green areas is mainly empirical. For this, our research aims to contribute with the scientific knowledge base for purpose designing of technosols. Since iron minerals play an important role for many different functions of soils, we simplified a technique to incorporate and stabilize iron minerals in a substrate: a sand coated with an amorphous iron (hydr)oxide, a 2-line ferrihydrite (2L-FH).

Materials and methods

The 2L-FH was precipitated by neutralization of a concentrated FeCl3 solution. The suspension was homogeneously mixed with the sand and the mixture was dried at 35 °C. The mechanical stability of the 21 2L-FH-coated sand was determined by shaking the aggregates in water for 0, 1, 10, 100, and 1 000 min. The degree of coating detachment and the properties of the coating after shaking were characterized through (a) Fe content, (b) zeta-potential and particle size of the detached particles, (c) the specific surface area (SSA) of the coated sand, and (d) its surface structure using scanning electron microscopy (SEM). A phosphate adsorption isotherm was performed to measure the P-sorption capacity of the shaken samples and to test the 2L-FH-quartz attachment stability against the surface charge reduction of the 2L-FH associated with P adsorption.

Results and discussion

A reduced Fe loss (30 %) and smaller sizes of the coating detached particles in the sample shaken for 1 000 min indicate that a fractioning and reattachment of these aggregates occurred during the agitation process, resulting in a smoother surface (SEM), and a larger SSA and P-sorption capacity. The coated shaken samples showed P-adsorption capacities (5.3–6.34 μmol P g?1) comparable to high loadings of phosphate in soils, and low detachment of Fe (7–14 %) in spite of negativity surface charge increase.

Conclusions

The practical novel coating process along with the 1 000-min shaking produced a mechanical resistant and P-adsorptive effective coated sand that could sustain the needs of plants in further experiments.
  相似文献   

2.
Purpose

Urban greenery provides a series of benefits for the environment and inhabitants of cities. However, the substrate preparation mostly implies the mining and erosion of valuable natural soils (e.g., peat). Purpose-designed substrates, preferably made of waste materials, could avoid the extraction damage. The present work aims at improving the production and lowering the costs of a functional stably coated sand with ferrihydrite. This functional substrate combines the Fe (hydr)oxide sorptive capacities and the fast drainage of sand. Thus, secondary raw materials were tested: a dredged sand and three Fe (hydr)oxides; one from groundwater, an industrial intermediate product, and a mining by-product.

Materials and methods

Three Fe (hydr)-oxides were structurally characterized by XRD, XRF analysis, and SSA measurements. Further, amorphous Fe (hydr)oxide concentrations were determined. Sludges of these Fe (hydr)oxides in different concentrations were hand-mixed with a dredged and a mined sand, and dried at 35 °C. The stabilization of the coating was made by heavy shaking (250 rpm) the coated sand with water (3:1 w:w) for 0, 10, and 1000 min, washing and drying at 35 °C afterwards. Thereafter, the effectiveness of this treatment was determined by the Fe concentration and pH of the coated sand, along with the particle size of the detached aggregates during shaking, and the pH in the washing water. The morphology of the coating was observed by scanning electron microscopy.

Results and discussion

All Fe (hydr)oxides were 2-line ferrihydrites with large SSA, and coated both sands. Only after 1000 min shaking, homogeneous and small ferrihydrite aggregates covered the sands surfaces (verified by SEM and particle size). The impurities of the ferrihydrites affected the stabilization of the coating. Calcium carbonates enhanced the aggregation and reattachment of the Fe aggregates to the sand during shaking, while phosphate reduced the reattachment by stabilizing the aggregates in the suspension.

Conclusions

Two out of three ferrihydrites were suitable to develop a stable coating. To coat dredged sand with both ferrihydrites lowers the cost and production time to obtain a functional substrate. One ferrihydrite has a high pH due to its high CaCO3 content, and sand coated with it may be used as an amendment for acidic clayey soils.

  相似文献   

3.
Reactions of zinc with iron-oxide coated calcite surfaces at alkaline pH   总被引：1，自引：0，他引：1  
Both iron oxides and carbonate minerals, such as calcite, can sorb zinc (Zn), and therefore are important in controlling the solution concentration and availability of Zn to plants growing in calcareous soil. When present together, interactions between these components affect their sorption behaviour. We investigated changes in the reactions of Zn with calcite at alkaline pH, as the calcite surface was progressively coated by iron oxide. Coated calcite surfaces were prepared that had from 0.05 to 1.45% iron oxide. The initial concentration of Zn and the amount of iron oxide on the calcite were the most critical factors affecting adsorption, precipitation of solid phases, and the desorbability of sorbed Zn. For pure calcite at small initial Zn concentrations (< 2.5 × 10?5 m ) adsorption was dominant; with increasing concentration, precipitation of hydrozincite (ZHC) became more important. With increasing amounts of iron oxide the amount of Zn adsorbed increased, the desorbability of the Zn decreased, and precipitation became progressively less evident, and at 1.45% iron oxide content there was no evidence of any precipitation of ZHC. The calculated maximum adsorption attributable to the iron oxide coating was inversely proportional to the thickness of the oxides on the calcite, and greatly exceeded that of iron oxide as a separate phase. The common occurrence of iron‐coated carbonates in calcareous soils and their capacity to adsorb Zn contributes to the problems of Zn deficiency, for which these soils are noted.  相似文献   

4.
Effect of iron oxide on phosphate sorption by calcite and calcareous soils   总被引：3，自引：0，他引：3  
Pure calcite (AR grade CaCO3) was treated with ferrous perchlorate solution to give a surface coating of iron (Fe) oxide. Maximum sorption (xm) of phosphate (P) by the calcite increased from 18.2 to 160 mg P kg?1 as the amount of coating increased from 0.00 to 16.0 g Fe2O3, kg?1 CaCO3. Evidence for Fe oxide coatings on carbonate minerals in two Sudanese soils was obtained by optical microscopy and electron-probe microanalysis. The relative contributions of carbonate and Fe oxide minerals, and Fe oxide coatings to P sorption in these soils were calculated, based on an assumed model of oxide distribution. Separate-phase Fe oxide was the major contributor (30–40%) to P sorption in the soils; the Fe oxide coatings on carbonate minerals were only minor contributors (< 6%), and the contribution of uncoated carbonate minerals was found to be negligible (<1 %). These results suggest a very minor role for carbonate minerals, even when coated with Fe oxide, in the sorption of P by these calcareous, Sudanese soils.  相似文献   

5.
Rare earth mineral based adsorbent viz. lanthanum oxide was investigated for potential application in defluoridation of drinking water for isolated and rural communities. Results of batch experiments indicated about 90% removal in 30 min from a 4 mg L−1 synthetic fluoride solution. The effects of various parameters like contact time, pH, initial concentration, and sorbent dose on sorption efficiency were investigated. Adsorption efficiency was dependent on initial fluoride concentration and the sorption process followed BET model. Variation of pH up to 9.5 has insignificant effect on sorption and beyond a pH of 9.5, the effect was drastic. Among anions investigated, carbonates exhibited high detrimental effect on fluoride adsorption while anions like bicarbonates, chlorides, and sulfates did not seriously affect the process. Adsorbent showed negligible desorption of fluoride in distilled water. Alum was more effective regenerant than HCl and NaOH. Results of cyclic regeneration with alum indicated that the sorbent could be regenerated for ten cycles without significant loss of sorption capacity. Studies with upflow fixed-bed continuous flow columns indicated the usefulness of sorbent for fluoride removal in continuous flow process.  相似文献   

6.
A novel silicate mesoporous material, SBA-15 supported Fe2O3, was synthesized by post-synthesis method via ultrasonic-assisted route. The desulfurization test from a gas mixture containing 0.1 vol% H2S was carried out over SBA-15 supported Fe2O3 in a fixed-bed system at atmospheric pressure and room temperature. The effects of the chemical nature of Fe2O3 and the textural properties of the material on desulfurization capacity were studied. Materials before and after the desulfurization test were characterized using nitrogen adsorption, XRD, TEM, FTIR, XPS, ICP and other standard methods. The characterization results suggest that modification process does not change the two-dimensional hexagonal mesostructure of SBA-15. Iron species disperses inside channels and the outside surface in the crystalline phase of iron oxide. The material with iron content of 31.3 wt% presented highest H2S uptake capacity. Structural properties of the material also play important roles in desulfurization performance besides the catalytic effects of iron oxide. The basic feature of material and enough oxygen supply are benefit for the reaction. SBA-15 supported Fe2O3 can be an effective alternative to capture H2S from gas streams.  相似文献   

7.
Abstract

The environmental impact of crop wastes and the high cost of peat moss (PM) force scientists to find alternative growing media. In a pot experiment, peanut shell (PS) and corn wastes (CWs) were evaluated as growing media in comparison with PM in three different mixing ratios with washed sand. The mixing ratio were M1?=?1:1 raw material to sand, M2?=?1:2 raw material to sand, and M3?=?1:3 raw material to sand. The tested plant was lettuce (Lactuca sativa L.). The obtained results showed that PS medium contained available nitrogen (N) and phosphorus (P) higher by 121% and 38% above the PM medium. Availability of potassium (K) in CW medium was higher by 167% than PM. The EC, pH, OC, and C/N ratio of PM were higher by 227%, 4%, 128%, and 99% above the CW and by 1,473%, 9%, 74%, and193% above the PS, respectively. The highest significant values of growth parameters were recorded in PM medium. The highest total cost and lowest net profit were recorded with the use of PMM1, whereas the lowest cost and the highest net profit were obtained with PSM2. Physiochemical characteristics of peanut shell suggested that it can be economical alternative growing media for PM.  相似文献   

8.
Abstract

Rice–wheat cropping system covers about 24 million hectares in China, India, Pakistan, Nepal, and Bangladesh, and zinc deficiency is widespread in rice–wheat belts of all these five countries. The current practice of applying zinc sulfate heptahydrate (ZnSO4 · 7H2O) to soil is problematic because of the poor quality of the nutrients available in the market to the farmers. Zinc (Zn)–coated urea is therefore being manufactured to guarantee a good‐quality Zn source. This article reports the results from a field study conducted to study the relative efficiency of zinc sulfate and zinc oxide (ZnO)–coated ureas in rice–wheat cropping system. The highest grain yield of rice–wheat cropping system was obtained with 2.0% coating of urea. Zinc sulfate was also a better coating material than ZnO. Partial factor productivity, agronomic efficiency, apparent recovery, and physiological efficiency of applied Zn decreased as the level of Zn coating was increased.  相似文献   

9.
Eruptions from Talang volcano on 12 April 2005 distributed volcanic ash over portions of the Solok District of West Sumatra, Indonesia. Unleached and leached pristine volcanic ash were collected immediately after the eruption, and the third sample was collected after 2 years. The mineralogy and chemical properties of pristine volcanic ash and volcanic ash deposits that were weathered for 2 years from the 2005 eruption of Mt. Talang, Sumatra, were studied to characterize the volcanic ash, identify the primary minerals present, and determine its chemical properties. Results showed that the volcanic ash contained 30% noncrystalline minerals (or volcanic glass); the remaining ash is composed of crystalline minerals such as labradorite, hypersthene, augite, hornblende, olivine, opaque ferromagnetic minerals, and rock fragments. Notable differences in pH values were observed as the pH tended to become more acidic from the unleached, leached, and weathered volcanic ash, but the ash did not give much response to the sodium fluoride (NaF) test. Total sulfur gradually decreased from 3.28% in unleached ash to 1.93% after 2 years. Available phosphorus (P) in the unleached volcanic ash was 68 mg kg?1, and this value was decreased by 15 % after 2 years of being exposed to the atmosphere, while phosphate retention ranged between 52.8% and 66.8%. Cation exchange capacity (CEC) was low with the value of 10 cmolc kg?1 although base saturation was high, exceeding 75%. The low acid oxalate–extractable silicon (Si), aluminum (Al), and iron (Fe) values of 0.07%, 0.25% and 1.17%, respectively, show the scarcity of secondary amorphous compounds in the ash. Total elemental analysis indicated that no differences were found in total silica oxide (SiO2) content of all samples, with a value about 56%, and this volcanic ash can be classified as basaltic andesite. We observed that removal of chemical elements by leaching was large for calcium oxide (CaO), magnesium oxide (MgO), and sodium oxide (Na2O) as the values decreased in time. Solid-state 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) studies indicated that Al occurred in both tetrahedral and octahedral forms. Silicon was not present in the tetrahedral layer. An intense peak at ?92 ppm was indicative of the presence of aluminosilicates.  相似文献   

10.
The oxygen status in soils is fundamental to a number of earth-science processes including biological, physical and chemical interactions. Since oxygen is time consuming and often difficult to measure in soils, this research explores the use of zero-valent iron rods as a means of estimating oxygen content in soils. Zero-valent iron rods (polished nails) were placed in three soil toposequences and the surface coatings formed by oxidation were compared to measured oxygen concentrations taken every three weeks for one year. When water was present in the soils, the oxygen was measured as dissolved oxygen and in drained conditions it was reported as percent. Coatings on iron metal rods inserted in the soil appear to correlate well with specific oxygen ranges. Rods in soils with O2 concentrations below about 2 mg l− 1 do not develop bright (7.5YR 4/4 to 5/8) oxide/oxyhydroxide coatings, but instead formed black (10YR 2/1–2) coatings. Rods in soils with O2 concentrations between about 2% to 5% develop variegated bright (7.5YR 4/4 to 5/8) oxide/oxyhydroxide coatings indicating soil drainage and microsite differences in O2 concentrations. Rods in soils with O2 concentrations above about 5% with adequate moisture are almost completely coated with bright (7.5YR 4/4 to 5/8) iron oxide/oxyhydroxides. Mineralogy of oxide/oxyhydroxide coatings could not be established by XRD presumably due to the short-range order crystal structure of the metal oxide/oxyhydroxides. This method provides a simple and inexpensive means to qualitatively estimate the ranges of O2 status in soils. This research may have implications in hydric soil determination, horticultural and agricultural applications, as well as, remediation techniques.  相似文献   

11.
The research was focused on the synthesis and characterization of zinc (Zn)-coated urea fertilizer. Zinc oxide (ZnO) particles were coated on urea granules through two different coating techniques, i.e., slurry coating and wet coating, and the release rate of the coated Zn was measured up to 24 hours. Slurry coating technique showed better Zn release rate and morphology of coated urea granules as compared with wet coating technique using different binders, i.e., water, molasses, paraffin oil, and the combined mixture of honey bee wax and gum arabica. Urea granules synthesized through wet coating technique have a low amount of Zn as compared with slurry-coated urea granules. Urea granules coated through slurry coating technique and molasses, paraffin oil, and water (MPW) as a binder were the best in term of coating efficiency, uniform size distribution of ZnO-coated particles, granule's morphology, and release rate of Zn from coated formulations.  相似文献   

12.
A granular media synthesized using iron oxide nanoparticle-coated alumina (IONA) has been demonstrated as an effective solid catalyst in the heterogeneous catalytic ozonation of para-chlorobenzoic acid (pCBA). TEM analysis showed that iron oxide nanoparticles with an average size of 5–20 nm were well-coated onto an alumina surface. It was determined that the iron oxide nanoparticle coating increased the specific surface area by 54 times and the functional group density by 1.5 times. During catalytic ozonation at acidic pH levels, it was clearly observed that IONA increased the degradation of pCBA (98 %) through effective hydroxyl radical formation compared to bare alumina (9 %) under continuous ozonation processes. In comparing the R ct value, which represents the ratio of ozone exposure to hydroxyl radical exposure, the R ct of IONA was approximately four times higher than for bare alumina. In addition, IONA showed good stability for catalytic ozonation of pCBA in the reusability tests.  相似文献   

13.
Four kinds of slow release fertilizers were prepared out by coating common compound fertilizer [nitrogen (N)-phosphorus pentoxide (P2O5)-potassum oxide (K2O):15-15-15] with four kinds of superfine phosphate rock powder (SPRP) which accounting for 60% of the total coated materials in mass. Electronic microscope scanning, static water releasing test, soil incubation experiment, and a field experiment were conducted on their nutrient release mechanisms and their effects on physiologic traits of Chinese cabbage. The results showed that all these four kinds of SPRP could markedly improve microstructure and thus release rate. However, their capacity was inferior to controlled release fertilizer (CRF). The four homemade fertilizers increased chlorophyll content, photosynthetic rate, and transpiration rate in the leaves of Chinese cabbage during its late growth stage, and improve the superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) enzyme activities during its ball period. In addition, the four homemade fertilizers improved yield by 20.62%～33.41% and 18.94%～24.44%, respectively, over the common compound fertilizer during 2009 and 2010, and improved sugar-acid and soluble sugar and VC contents of the head of Chinese cabbage at the harvest stage. There are not obvious differences of physiological traits between the J2 coated CCF fertilizer (JCRF2), Y2 coated CCF fertilizer (YCRF2), and Resin coated CCF fertilizer (CRF). Nutrient release characters and agricultural effect of four homemade fertilizers follow the order: JCRF2≈YCRF2>JCRF1≈YCRF1.  相似文献   

14.
周敏  徐则林  刘新  杜辉辉 《土壤》2022,54(4):810-816
本研究选取代表性层状硅酸盐蒙脱石，两种代表性氧化铁(水铁矿、针铁矿)，合成蒙脱石-水铁矿、蒙脱石-针铁矿二元复合体，通过宏观吸附以及光谱学技术探究钨(WO42-)在蒙脱石-氧化铁复合体上的吸附行为和潜在机制。结果表明：氧化铁紧密覆盖在蒙脱石表面，使表面颗粒更加细小；钨的吸附量随pH升高而降低，3种吸附剂对钨吸附量大小顺序为：蒙脱石-水铁矿>蒙脱石-针铁矿>蒙脱石；原位红外光谱实验表明，钨在蒙脱石表面主要以外圈络合物形式存在，而在蒙脱石-氧化铁复合体上形成内圈络合物(Fe-O-W)，且在低pH时，形成聚合态钨；X-射线光电子能谱进一步表明，针铁矿和水铁矿表面铁羟基参与了钨的络合反应。本研究证实，氧化铁覆盖不仅增大蒙脱石对钨的吸附量，而且使钨由外圈络合物形态转变为内圈络合态，进一步生成聚合态钨。研究结果对预测钨在土壤中的迁移转化、生物有效性和归宿有重要指导意义。  相似文献   

15.
The influence of ion exchange processes on the apparent solubility of fluoride compounds was examined by observing changes in free F? and total F levels when suspensions of sparingly soluble fluoride species (e.g., CaF2, AlF3) and aluminium smelter wastes were equilibrated with a range of materials having different cation exchange capacities. The exchanger materials used included synthetic resins, clay minerals, a humic acid and Mn(IV) oxide. The amount of fluoride ion released from the fluoride salts and F? rich wastes was found to increase in the presence of solids capable of exchanging cations, and the magnitude of the effect tended to be determined by the number of exchange sites available and the affinity of the fluoride compound cation for the exchange material. In some instances (e.g., with illite and alumina wastes) the released fluoride ion attacked the substrate and formed soluble complex ions.  相似文献   

16.
Copper oxide nanoparticles were immobilized on quartz sand and their catalytic activity for the degradation of an organic dye was investigated. The use of nanoparticles as catalysts for non photo-induced oxidation of water contaminants is relatively new. The CuO catalyst has shown promising results when suspended in free form in batch systems. Because heterogeneous catalysis is often the preferred mode of operation for application of catalytic technology, we studied the effect of immobilization of the nanoparticles on quartz sand in a flow-through system and its implication for the catalytic process. The coated sand was packed in a column and its catalytic activity for the degradation of an organic dye was investigated in a series of flow-through experiments with hydrogen peroxide as the oxidant. Control experiments with uncoated sand were also performed for comparison. The coated sand demonstrated high catalytic ability, achieving complete oxidation of the dye. During the reaction, CO2 was produced, leading to a decrease in the water saturation in the column and reduced contact surface between the nano-CuO catalysts and the dye solution. The degradation was improved by enabling a longer residence time of the dye in the column, yielding up to 85% degradation of the dye. These results suggest that CuO nanoparticle-coated sand is an efficient catalyst for complete degradation of the organic dye.  相似文献   

17.
汉江与嘉陵江源区土壤团聚体分布特征及机制研究   总被引：1，自引：1，他引：0  
以汉江与嘉陵江源区黄土母质上发育的土壤为研究对象,通过对土壤团聚体和理化性质的试验分析和数据解析,研究了两地土壤团聚体的分布规律及发生机制。结果表明:(1)汉江源区(LJH)团聚体的R 0.25、MWD、GMD值由A层的83.73%,2.17和1.11分别降为C层的59.18%,0.40和0.26,嘉陵江源区(YJS)由A层的69.72%,1.03和0.46降为C层的56.55%,0.52和0.27,分形维数(D)则随土层深度的加深而增大,即前者的D值由A层的2.46增为C层的2.53,后者由A层的2.50增为C层的2.57,表明土壤团聚体稳定性随土层深度增大而减弱,其中>2,1~2 mm团聚体对保持土壤的稳定性具有重要贡献。(2)土壤有机质、铁铝氧化物和颗粒组成中的粉粒是促进土壤大团聚体形成并维持其稳定性的重要影响因素,而SiO 2、K 2O、黏粒、砂粒和碳酸钙在不同土壤环境中对团聚体稳定性起到截然相反的作用,即前三者在LJH剖面中对团聚体稳定性不利,在YJS剖面中反而有利于维持其稳定性,后两者促进LJH剖面团聚体形成,却破坏YJS剖面稳定性,Na 2O水溶解后则对团聚体具有分散作用。(3)汉江源区的土壤,A层团聚体稳定性强于嘉陵江源区,粉粒、有机质和铁铝氧化物为其主导因素,Bt层土体致密,通透性弱,不利形成团聚体,稳定性弱于后者,C层为母质层,两地团聚体稳定性皆较差,其不同发生层之间土体稳定性的差异要大于嘉陵江源区。  相似文献   

18.
为探讨C36多元醇(简称C36)对C18多元醇(简称C18,对照)包膜材料缓控释性能的影响,该文以C18为对照膜材,将C36与C18分别按照质量比1:2、2:3、1:1共混聚合制备成3种新型包膜材料,在相同工艺下依次制造成包膜厚度均为2.5%(膜材占核芯肥料的百分比)的包膜尿素,分别记作PCU1、PCU2、PCU3、PCU4,其中PCU1为对照。通过坠落撞击前、后包膜尿素的释放率评价C36作为包膜材料的效果。研究结果表明:C36与C18共混聚合包膜尿素的外观及耐撞击性能明显优于对照处理的,表现为包膜层光泽明亮、膜质均匀、膜层韧性好,同期静水培养的颗粒表面积较对照的增加了23%。该文提出了肥效期保持率(tR)的概念,并用其评价包膜肥料耐撞击性能。共混聚合物C36:C18比例为2:3时,包膜尿素耐撞击性能最优,受撞击后肥效期保持率tR可高达88%左右,为对照处理的2.5倍以上。该处理包膜尿素的初期溶出率、微分溶出率最小,与对照PCU1处理的无明显差异。C36嵌入C18共混聚合生成的新包膜材料对包膜尿素肥效期的影响与两者的比例和包膜材料的用量有关,当C36:C18为2:3,包膜材料用量(2.5%)小于常规用量(3%~4%)时,虽然包膜尿素的肥效期没有延长,但是包膜完整、膜层均匀、韧性强,在包膜肥受到强烈撞击的情况下能够很好地保持原有肥料的肥效期,即能保持包膜肥料的缓控释性能。因此,在C18多元醇嵌入适量C36多元醇是改良C18多元醇包膜材料,增加其包膜肥肥效期保持率的有效方法。  相似文献   

19.
Abstract

The capacity of 36 Western Australian soils to adsorb phosphorus (P) was measured by three different methods: P retention index (PRI), P buffering capacity (PBC), and P adsorption (PA). The P adsorption values measured by all three methods varied markedly with soil type. When the P adsorption values were correlated with several soil properties, using simple and multiple linear regressions, PRI, PBC, or PA values were found to be significantly correlated with the aluminium oxide content of the soils. In addition, PBC and PRI was correlated with organic carbon content. The role of aluminium oxide (Al2O3) in the soil was apparently more important in determining the P adsorption capacity of the soils than that of iron (Fe), even though the iron oxide (Fe2O3)content of all the soils studied was consistently higher than the aluminium oxide content. The relationship between P adsorption and the selected soil properties, as determined by multiple linear regression, explained 45–59% of the variation: arabic PRI = ‐10.87 + 9.94 organic C (%) + 160.02 Al2O3 (%), r2 = 0.45.

arabic PBC = ‐0.004 + 1.532 organic C (%) + 22.26 Al2O3 (%), r2 = 0.57.

arabic PA = 3.52 + 248.75 Al2O3 (%), r2 = 0.59.

  相似文献   

20.
In this investigation, a novel water-insoluble slow-release fertilizer, biuret polyphosphoramide (BPAM), was formulated and synthesized from urea, phosphoric acid (H(3)PO(4)), and ferric oxide (Fe(2)O(3)). The structure of BPAM was characterized by Fourier transform infrared (FTIR) spectroscopy. Subsequently, a coated slow-release BPAM fertilizer with superabsorbent was prepared by ionic cross-linked carboxymethylchitosan (the core), acrylic acid, acrylamide, and active carbon (the coating). The variable influences on the water absorbency were investigated and optimized. Component analysis results showed that the coated slow-release BPAM contained 5.66% nitrogen and 11.7% phosphorus. The property of water retention, the behavior of slow release of phosphorus, and the capacity of adsorption of cations were evaluated, and the results revealed that the product not only had good slow-release property and excellent water retention capacity but also higher adsorption capacities of cations in saline soil.  相似文献   

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