Structure Characterization and Dephosphorization Effect Analysis of Oyster Shell-silica Micropowder Waste Water Dephosphorization Materials

In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping oyster shell and silica micro-powder.Different concentrations of phosphorus-contained waste water were simulated with potassium dihydrogen phosphate solution,the effect of dephosphorization was tested with phosphomolybdenum blue spectrophotometer method,and the crystal phase and microstructure of materials were characterized by XRD and SEM methods. It was indicated that dephosphorization was completed in 6 h when the initial phosphorus concentration in waste water was lower than 15 mg/L, and the dephosphorization time prolonged as the increase of phosphorus concentration. It was observed that the pH value of waste water influenced dephosphorization significantly, and neutral subalkalic environment favored dephosphorization. When the pH value was 11, the efficiency of dephosphozation was the greatest. For waste water with an initial concentration of 20 mg/L, the dephosphozation rate is close to 100% in8 h.

Preparation of Multifunctional β-hemihydrate Gypsum using Oyster Shell Powder as the Partial Replacement of Ag/TiO2 Particle

This work aimed to use oyster shell powder (OSP) as the partial replacement of Ag/TiO2 particle to obtain multifunctional β-hemihydrate gypsum.Thus,the β-hemihydrate gypsum was mixed with different contents of OSP and Ag/TiO2 particle.Antibacterial and MB removal experiments were conducted to assess the antibacterial characteristic and photocatalytic activity of β-hemihydrate gypsum with Ag/TiO2 particle and OSP.Besides,the formaldehyde degradation test was carried out to evaluate its formaldehyde removal ratio.Moreover,their setting times,compressive and flexural strengths at 1,3,and 28 days were comparatively analyzed.The experimental results prove that the composite use of OSP and Ag/TiO2 particle provide feasible multifunction for the β-hemihydrate gypsum.They can further improve the bactericidal rates and exhibit extra MB removal ratios compared with the gypsum plasters with single Ag/TiO2 particle.Besides,they can increase the formaldehyde degradation ratios,and this promotion is related to the introduction of Ag/TiO2 particle.However,OSP delays the initial setting time but promotes the final setting time of β-hemihydrate gypsum,and Ag/TiO2 particle hardly affects the setting times.Furthermore,OSP reduces the strengths of plasters at 1,3,and 28 days.But in general,the composite addition of OSP and Ag/TiO2 particle increase the compressive and flexural strengths of gypsum plasters at 1,3,and 28 days.These results provide theoretical guidance for the recycling of OSP and the preparation of gypsum-based products with antibacterial and formaldehyde degradation capabilities.

Biological oyster shell waste enhances polyphenylene sulfide composites and endows them with antibacterial properties

To date,there is no research that deals with biological waste as fillers in polyphenylene sulfide(PPS).In this study,oyster shells were recycled and treated to prepare thermally-treated oyster shells(TOS),which were used as PPS fillers to make new bio-based antibacterial composite materials.The effect of varying the content of TOS was studied by means of structure and performance characterization.PPS/TOS composites were demonstrated to have an antibacterial effect on the growth of E coli and S.aureus.Qualitative analysis showed that when the TOS content was≥30%and 40%,the composite materials had an apparent inhibition zone.Quantitative analysis showed that the antibacterial activity increased with the TOS content.Fourier transform infrared spectroscopy indicated the formation of hydrogen bonds between the molecular chains of TOS and PPS and the occurrence of a coordination reaction.At 10%TOS,the composite tensile strength reached a maximum value of 72.5 MPa,which is 9.65%higher than that of pure PPS.The trend of bending properties is the same as that of tensile properties,showing that the maximum property was reached for the composite with 10%TOS.At the same time,the crystallinity and contact angle were the highest,and the permeability coefficient was the lowest.The fatigue test results indicated that for the composite with 10%TOS,the tensile strength was 23%lower than static tensile strength,and the yield strength was 10%lower than the static yield strength.The results of the study showed that TOS not only could reduce the cost of PPS,but also could impart antibacterial properties and enhance the mechanical and,barrier properties,the thermostability,as well as the crystallinity.

Preparation of Iron-Pillared Bentonite/Oyster Shell Composite and Phosphate Adsorption in Water

Iron-pillared bentonite(FB)was prepared by Fe(III)modified bentonite,and then the composites(FB-OS)were prepared by iron-pillared bentonite and oyster shell powder.The composites were characterized by FTIR,SEM,TGA,and EDS,and the phosphorus removal test was carried out.The results showed that FB-OS contained a large amount of CaO.Its structure was compact,but there were gaps in it.The maximum bending stress and compressive strength were 43.7 N and 0.927 MPa,respectively.The phosphorus removal test showed that the phosphorus removal rate of FB-OS was more than 90%,and measured the maximum adsorption capacity was 48.31 mg/g.A large amount of spherical products were produced on the surface and inside of FB-OS after phos-phorus removal,it was speculated that spherical products were amorphous calcium phosphate in the paper.Ana-lysis indicated that there was chemical adsorption during phosphorus removal.The kinetic equation of phosphorus adsorption by FB-OS was qt=10:193t/1+2:574t (R^(2)=0.995).The adsorption rate was mainly controlled by outerfilm diffusion and intraparticle diffusion.

改性剂对高密度聚乙烯复合材料的性能研究

采用回收的牡蛎壳经高温煅烧改性后为增强填料,马来酸酐接枝聚乙烯(PE-g-MAH)为改性剂与高密度聚乙烯采用熔融共混法制备了纳米复合材料。使用电子万能拉力机、X射线衍射仪(XRD)和差示扫描量热仪(DSC)对复合材料的结构、形貌和结晶性能进行了表征。探究了改性剂以及牡蛎壳粉含量对高密度聚乙烯复合材料综合性能的影响。结果表明:煅烧后的牡蛎壳粉可以提升复合材料的力学性能,且改性剂可以很好改善牡蛎壳粉与高密度聚乙烯之间的相容性,当牡蛎壳粉的质量含量为1%时,复合材料的综合性能最好。

牡蛎壳粉对水产品废水中化学需氧量吸附特性的研究

采用废弃牡蛎壳粉热改性对水产品废水中化学需氧量(CODcr)进行吸附试验,研究了天然牡蛎壳粉、热改性400,850℃条件下牡蛎壳粉用量、温度、pH值、振荡时间对牡蛎壳粉吸附水产品废水中的CODcr影响。同时,以热改性850℃牡蛎壳粉为研究对象进行正交试验。结果表明,牡蛎壳粉对CODcr的最佳吸附条件为牡蛎壳用量1.5 g,温度35℃,pH值8,振荡时间30 min。在此条件下,牡蛎壳粉对废水中CODcr的吸附率可达到72.52%。影响牡蛎壳粉对水产品废水中CODcr的吸附的因素依次是牡蛎壳粉用量、温度、pH值、振荡时间,热改性850℃牡蛎壳粉可用于水产品废水处理。

水分管理配施锰肥对牡蛎壳粉调控水稻镉吸收的影响

为研究水分管理配施锰肥对牡蛎壳粉调控水稻Cd吸收转运的效果,采用盆栽试验,在两种水分管理(持续淹水、干湿交替)条件下,分析了水稻抽穗前后牡蛎壳粉配施不同用量硫酸锰肥(0、50、100 mg·kg-1)对根际土壤Cd、Mn形态及含量和水稻Cd、Mn含量分布以及水稻根系Cd吸收转运OsNramp5基因表达的影响。结果表明:单施牡蛎壳粉(OS处理)在两种水分条件下均显著降低了土壤有效态Cd和有效态Mn含量,在持续淹水条件下对糙米Cd含量没有显著影响,但在干湿交替条件下显著降低了糙米中Cd含量。在持续淹水条件下,与OS处理相比,牡蛎壳粉配施锰肥(OSMn处理)可使土壤有效态Mn含量显著增加5.4%~10.9%;OSMn处理根OsNramp5相对表达量上调85.6%~105.9%,促进了水稻对Cd的吸收;OSMn50处理铁膜、根和秸秆中Cd含量分别增加了46.9%、52.9%、33.7%,但秸秆-糙米中Cd的转移系数降低了47.8%,糙米中Cd含量降低了30.0%,随着Mn肥添加量增加,OSMn100处理铁膜-根、秸秆-糙米中Cd的转移量分别增加了35.3%、23.9%,糙米中Cd含量增加了25.2%。在干湿交替条件下,随着Mn肥添加量增加,OSMn处理土壤有效态Mn、土壤无定形和游离态Mn氧化物含量显著增加,而土壤有效态Cd含量逐渐降低;与OS处理相比,OSMn50处理根OsNramp5的相对表达量增加了256.8%~322.8%,显著增加了水稻不同部位Mn含量,但对糙米和根中Cd含量没有显著影响;OSMn100处理秸秆-糙米中Cd的转移系数增加了38.9%,水稻糙米中Cd含量增加了15.3%。研究表明,在持续淹水条件下,牡蛎壳粉配施50 mg·kg-1Mn肥可进一步降低水稻糙米中Cd含量,但过量配施Mn肥会促进水稻籽粒中Cd的累积,与干湿交替相比,牡蛎壳粉配施Mn肥在持续淹水条件下能更有效地降低糙米Cd累积。

牡蛎壳粉沥青胶浆路用性能研究

基于“双碳”背景下,以拓宽牡蛎壳绿色废物利用为途径,探索其用作沥青矿粉的可行性。通过制备牡蛎壳矿粉进行微观特性分析发现,与白云岩矿粉相比,牡蛎壳粉末颗粒更细,比表面积更大,表面更粗糙,密度更低,具有更优的黏结力。在此基础上进一步通过动态剪切流变、多重应力蠕变恢复和弯曲梁流变等试验对比了5种粉胶比条件下牡蛎壳粉沥青胶浆的路用性能,从而确定了最佳粉胶比掺量和施工温度。研究结果表明:与白云岩矿粉沥青胶浆相比,牡蛎壳粉沥青胶浆具有更优的高温抗车辙性能和力学稳定性,其低温性能虽略逊于白云岩矿粉沥青胶浆,但仍满足较好的低温抗裂性能要求。鉴于牡蛎壳粉具备良好的路用性能、经济性与环保性,其在路面新建及养护工程中具有较好的应用前景。

不同生育期施用牡蛎壳粉对小麦籽粒镉积累的影响

减少作物可食用部位镉(Cd)积累是降低人体Cd暴露风险的有效途径。牡蛎壳粉因能改善土壤酸化程度、促进作物增产和减少Cd在作物中的积累而备受关注。为明确不同生育期施用牡蛎壳粉对小麦籽粒Cd富集的影响,本研究设置不施用牡蛎壳粉(CK)、拔节期施用牡蛎壳粉和抽穗期施用牡蛎壳粉3个处理,分析不同生育期施用牡蛎壳粉对小麦各器官Cd积累和分配的影响。结果表明:拔节期施用牡蛎壳粉和抽穗期施用牡蛎壳粉都能显著增加小麦千粒质量及地上部干质量,小麦籽粒Cd含量分别降低24.9%和37.7%。2个时期施用牡蛎壳粉处理对籽粒总Cd吸收量影响不大,籽粒中Cd的分配比例略有增加。抽穗期施用牡蛎壳粉能更有效促进Cd在穗下节间的积累。总之,抽穗期是小麦籽粒中Cd积累的关键期,此时期施用牡蛎壳粉能增加Cd在穗下节间的滞留,减轻Cd对小麦植株生长的胁迫,小麦籽粒产量增加,从而导致小麦籽粒Cd含量的降低。

牡蛎壳粉-木醋液促进市政污泥好氧发酵的腐殖化

为提高市政污泥传统好氧发酵产品的肥效,该文以市政污泥为原料、稻壳为辅料,通过添加物料总质量15%的牡蛎壳粉(OS组)、添加2%的木醋液(WV组)及联合添加15%的牡蛎壳粉+2%的木醋液(OS-WV组),探究牡蛎壳粉联合木醋液对市政污泥好氧发酵腐殖化进程及其产物肥效的影响。结果表明,OS-WV组可优化堆体理化性质并提高氮磷养分,发酵结束时,OS-WV组发酵产物的TN、NH_(4)^(+)-N、NO_(3)^(-)-N、TP、Olsen-P分别达到19.15、0.025、0.43、23.89、1.74 mg/g,显著高于其他实验组;OS-WV组堆体的腐殖化程度更高,胡敏素(HU)向胡敏酸(HA)和富里酸(FA)转化的强度更大。傅里叶红外光谱结果分析表明,联用牡蛎壳粉和木醋液可促使堆体中多糖类物质降解,增加芳构化程度,从而强化了腐殖化过程;三维荧光光谱分析表明,牡蛎壳粉和木醋液在促进生成高分子量和结构复杂的腐殖质(HS)组分方面具有协同作用;经过为期40 d的小白菜盆栽实验,验证了OS-WV组发酵产物的植物促生长效果最佳。15%牡蛎壳粉联合2%木醋液施用于市政污泥好氧发酵堆体,可促进堆体腐殖化进程并提高发酵产物的肥效。

牡蛎壳粉施用量对酸性耕地土壤中砷、铬的钝化效果初探

为了将漳州市丰富的牡蛎壳资源充分应用于钝化修复酸性耕地土壤中砷(As)、铬(Cr)污染,以受As、Cr污染的弱酸性耕地土壤为对象,采用盆栽试验研究牡蛎壳粉施用量对土壤中As、Cr污染的钝化效果,试验设置5个牡蛎壳粉施用量梯度:0(CK)、0.2(Atr 1)、0.4(Atr 2)、0.6(Atr 3)、0.8 g·kg^(−1)(Atr 4)。结果表明:酸性耕地土壤经牡蛎壳粉处理后,随施用时间的推移土壤pH值呈增加趋势;施用后60 d,Atr 1、Atr 2、Atr 3、Atr 4处理土壤pH值分别比CK增加0.50、0.83、1.10和1.31个单位,牡蛎壳粉施用量与土壤pH值呈极显著正相关线性关系(P<0.01)。牡蛎壳粉处理对土壤中As、Cr全量无显著影响(P>0.05),而可显著降低土壤中As、Cr的生物有效性(P<0.05),Atr 1、Atr 2、Atr 3、Atr 4处理同CK比较,土壤中有效态As比率分别下降2.45%、3.37%、3.48%和3.66%,有效态Cr比率分别下降1.82%、2.99%、3.06%和3.52%。Atr 1、Atr 2、Atr 3、Atr 4处理修复土壤中As污染的钝化效果分别为30.21%、41.83%、42.90%和45.03%,Cr污染的钝化效果分别为44.01%、68.42%、70.10%和80.47%;牡蛎壳粉施用量与钝化土壤中As、Cr污染的效果具有抛物线型变化关系,相关系数(r)分别为0.9861和0.9893(P<0.01)。本研究结果表明,牡蛎壳粉对酸性耕地土壤中As、Cr污染均有良好的钝化效果,施用量分别为0.62 g·kg^(−1)和0.69 g·kg^(−1)土壤时,钝化修复土壤中As、Cr污染的效果最佳达47.06%和79.06%。本研究结果还需在大田生产上进一步验证。

牡蛎壳粉及其铝盐、铁盐改性产物处理高浓度含磷废水研究

牡蛎壳广泛应用于污水中磷的去除,但是将牡蛎壳作为吸附剂来处理高浓度含磷废水的研究较少。本研究以天然牡蛎粉为实验对象,探究牡蛎壳粉及其铁盐、铝盐改性产物对1000 mg·L^(-1)模拟含磷水的处理效果。结果表明,Langmuir和准二级动力学模型能更好地拟合牡蛎壳粉对高浓度含磷废水的吸附过程,R^(2)值分别为0.992和0.983。牡蛎壳粉对磷的理论饱和吸附量达到212 mg·g^(-1),且在pH为3时牡蛎壳粉对磷的吸附效果最好。当牡蛎壳粒径为100目时,其对磷的单位吸附量达到(41.96±4.58)mg·g^(-1)。在质量分数分别为1%~5%的铝盐、铁盐改性牡蛎壳粉获得的复合材料中,用1%Al(NO 3)3溶液改性的牡蛎壳粉对磷的吸附效果最好,单位吸附量达到了(55.73±4.34)mg·g^(-1),比未改性牡蛎壳粉提升了27%。本研究结果表明牡蛎壳及其铝盐、铁盐改性产物对高浓度含磷废水具有良好的除磷效果,值得进一步研究。

Study on the Structures and Properties of Copper Removal Adsorbent Prepared from Sinter-free Pulverized Oyster Shell Materials

A hollow tubular copper removal adsorbent was prepared with oyster shell and cement as the main raw materials. The effects of different formulas, different initial copper concentrations and different pH values of samples on the copper removal efficiency were investigated to determine the optimal conditions for copper removal. The content of copper in the wastewater is determined by Atomic Absorption Spectrophotometer. The microstructure and elemental composition of the samples were characterized by scanning electron microscopy（SEM） and EDS. As a result, the formula with the content of cement to be 8 wt% and the oyster shell powder of 92 wt% is optimal. Under the condition of 30 ℃, when the pH value was 9.0, the Cu2＋ adsorption capacity of the sample could reach 0.59 mg/g at 48 h. SEM analysis revealed that there are abundant pores in the sample, which is beneficial for Cu2＋ absorption on the adsorbent.

Structure and Property Characterization of Oyster Shell Cementing Material

Oyster shell powder was used as the admixture of ordinary portland cement.The effects of different addition amounts and grinding ways on the strength and stability of cement mortar were discussed and proper addition amount of oyster shell powder was determined.The structure and property changes of cementing samples with different oyster shell powder contents were tested by XRD and SEM means.The results revealed that compressive and rupture strengths of the sample with 10% oyster shell powder was close to those of the original one without addition.Stability experiment showed that the sample prepared by pat method had smooth surface without crack and significant expansion or shrinkage after pre-curing and boiling,which indicated that cementing material dosed with oyster shell powder had fine stability.XRD and SEM observation showed that oyster shell independently exists in the cementing material.

Synthesis of Calcium Hexaluminate from Waste Slag of Aluminum and Oyster Shell

Waste aluminum slag and oyster shell were used as raw materials to synthesize calcium hexaluminate（CA6）. The effects of different source materials of CaO and sintering temperature on the structures and properties of CA6 were investigated,respectively. The results show that compared to calcium oxide,oyster shell can lower the formation temperature of CA6,hence CA6 can be detected at 1300 ℃ by using oyster shell as the starting raw materials. Increasing the sintering temperature can promote the crystal growth. CA6 crystals show typical platelet shape,and its optimum sintering temperature falls in the 1450～1550 ℃ region. The bulk density is 1.54～1.83 g/cm^3,the apparent porosity is 44.1～55.2% and the flexural strength is 10.8～25.3 MPa.

Preparation of Calcium Phosphate with Oyster Shells

Oyster shells have received attention for use as a calcium resource. For this study, calcium phosphate was prepared from phosphoric acid and oyster shells. The influences of the concentration of phosphoric acid and pH in the preparation conditions were studied from the yields of calcium phosphate and unreacted carbonate, and the Ca/P ratios in precipitates. The yield of calcium phosphate and carbonate was low in the preparation condition with 0.1 mol/l of phosphoric acid. The obtained precipitates were the mixture of calcium hydrogen phosphate dihydrate and the unreacted calcium carbonate. The reactivity of the oyster shells with phosphoric acid was discussed from the yields and Ca/P ratios in precipitates.

改性牡蛎壳粉/高密度聚乙烯纳米复合材料的制备及其性能研究

将牡蛎壳进行回收,采用高温煅烧改性后与高密度聚乙烯采用熔融共混法制备了纳米复合材料。使用FTIR、XRD、SEM和TG对复合材料的结构、形貌和耐热性能进行了表征,并研究了改性后牡蛎壳粉对高密度聚乙烯性能的影响。结果表明,改性后的牡蛎壳粉可以提升高密度聚乙烯纳米复合材料的综合性能。当改性后牡蛎壳粉的含量为1%时,纳米复合材料的综合性能最好。

不同改良剂对酸性烟田的改良效果及其对烤烟生长的影响

为比较不同改良剂的烟田应用效果,本研究通过田间试验探究了碱渣、牡蛎粉和石灰3种改良剂对酸性烟田土壤酸度、烤烟产量与品质及经济效益的影响。结果表明,3种改良剂施用均有效提高土壤pH,降低交换性酸和可溶性铝(Al)的含量,提升土壤交换性盐基阳离子含量。碱渣对土壤酸度的改良效果最佳,可使土壤pH提高0.38个单位,交换性酸和可溶性Al含量降低90.9%和39.8%。同时,碱渣处理中土壤交换性Ca^(2+)和Mg^(2+)含量分别增加了72.8%和91.9%。随着土壤性质的改善,3种改良剂均促进了烤烟的生长,提升了烟叶产量与内在品质。3种改良剂使烟叶产量增加6.0%~9.5%,上等烟比例提高4.0%~16.9%,产值增加11.7%~19.5%,净增收益增加4593.00~9270.30元/hm^(2),其中碱渣的增产增收幅度最大。此外,改良剂的施用优化了烤烟化学成分组成,其中牡蛎粉处理烟叶的品质最佳。总体看,利用碱渣改良酸性烟田具有广泛的应用前景,但在实际应用中,需注意控制碱渣Na和Cl元素含量。

牡蛎壳粉改良膨胀土的工程特性及微观机理研究

为探究固体废弃物牡蛎壳粉对膨胀土工程特性的改良效果,以广西宁明膨胀土为研究对象,对牡蛎壳粉掺量分别为0%,3%,6%,9%和12%的膨胀土开展一系列胀缩特性试验以及干湿循环条件下的直剪试验,并通过SEM试验分析了改良前后膨胀土的微观结构特征。试验结果表明:牡蛎壳粉可有效降低土体的胀缩性,提高土体的黏聚力。土体的自由膨胀率、无荷膨胀率、有荷膨胀率、膨胀力、线缩率等随牡蛎壳粉掺量增加而降低,在牡蛎壳粉掺量为9%时有稳定趋势。牡蛎壳粉掺量为9%时,土体黏聚力达到峰值;所有掺量土体的黏聚力均随干湿循环次数增加而降低,均在干湿循环4次时趋于稳定,且掺牡蛎壳粉土体黏聚力的降低幅度要低于未掺量土体;经历6次干湿循环后,牡蛎壳粉掺量为9%土体的黏聚力相对于未掺量土体增加了42.38%。土体内摩擦角的变化规律性不明显,但整体上掺牡蛎壳粉土体的内摩擦角大于未掺量土体。微观结果显示掺入牡蛎壳粉增强了土体的稳定性,减缓了膨胀土在经历干湿循环后裂隙、孔隙的发育。牡蛎壳粉对膨胀土胀缩特性、强度特性等具有一定的改性效果。研究结果为实现牡蛎壳粉改良膨胀土提供理论基础数据。

牡蛎壳粉土壤调理剂对土壤理化性质及小白菜农艺性状和品质的影响

为探究牡蛎壳粉土壤调理剂对土壤理化性质及小白菜生长和品质的影响,以小白菜为试验对象,常规施肥为CK,设置增施750、1500、2250、3000、3750 kg·hm^(-2)(T1~T5)5个牡蛎壳粉土壤调理剂用量水平,以期筛选其在小白菜大田种植中的最佳施用量。结果表明,不同土壤调理剂用量均能提高小白菜产量和叶片相关生长指标,T3处理表现最好,小白菜株高、单株质量、叶面积和叶质量都显著高于CK,较CK分别提高4.49%、44.51%、18.25%和26.38%;增施土壤调理剂可以改善小白菜品质,提高土壤中氮元素含量,促进磷元素的吸收,小白菜蛋白质、钙和维生素C含量较CK最高分别增加10.97%(T3)、19.21%(T4)、33.74%(T2),土壤中全氮和碱解氮含量较CK最高分别增加5.65%和5.73%(T2)。综上,2250 kg·hm^(-2)牡蛎壳粉土壤调理剂施用量对提高小白菜产量和长势效果最明显,且能一定程度上改良土壤和提高小白菜品质。