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.

牡蛎壳粉对市政污泥好氧发酵过程重金属钝化的影响

为增强市政污泥好氧发酵过程重金属的钝化效果,通过添加质量分数为10%、15%、20%的牡蛎壳粉(OS)(标记为OS10、OS15、OS20)与市政污泥进行好氧发酵,探究其对重金属钝化的影响及作用机制。结果表明:与对照(CK)相比,添加OS优化了堆体理化环境,显著促进了Zn、Cu和Cr向稳定态转化,其中OS15效果最优,钝化率分别为55.81%、59.58%和47.28%;傅里叶红外光谱(FTIR)和X射线衍射(XRD)分析表明,OS15样品中存在较强的碳酸盐C—O振动峰,且在发酵后形成了新的重金属碳酸盐矿物;此外,添加OS显著增强了有机质降解相关菌群的丰度,冗余分析(RDA)表明,假单胞菌属(Pseudomonas)和黄单胞菌属(Luteimonas)与重金属的钝化呈显著正相关关系。综上,在市政污泥好氧发酵中添加OS可以增强重金属的钝化效果,以15%添加比例效果最优。

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.

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.

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.

牡蛎壳微粉改性水泥基复合材料性能及微观结构研究

以牡蛎壳粉部分替换传统水泥基材料,在实现牡蛎壳废物利用的同时可有效降低建材成本。利用牡蛎壳粉作为普通硅酸盐水泥掺合料,探讨其不同掺杂量及不同粉磨方式对水泥胶砂强度及安定性的影响,确定了牡蛎壳粉的适宜添加量,并用XRD、SEM及EDS等测试分析手段表征不同掺量下胶凝试块的结构及性能变化。实验结果表明,牡蛎壳的球磨方式对水泥胶砂强度有明显影响,掺加湿法球磨牡蛎壳粉的胶凝材料的强度高于相应的掺加干法球磨的样品。牡蛎壳粉的掺加量为5%时,试样的抗压强度和抗折强度分别达到49.2 MPa和7.55 MPa,显著高于未掺加的空白样品。通过安定性实验制得的试样经过预养、沸煮之后,表面均光滑、无裂纹,体积无明显膨胀或收缩,表明掺杂牡蛎壳粉的胶凝材料安定性良好。微观结构表征结果显示牡蛎壳粉在水泥胶凝材料中独立存在,主要起惰性填充作用。利用牡蛎壳微粉部分替代水泥基材料是可行的,既可以改善水泥基材料综合性能,又能节约材料成本、减少环境污染,具有良好的应用前景。

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.

牡蛎壳粉土壤调理剂施用量对土壤理化性质及茄子农艺性状和品质的影响

以‘农友704’茄子为试验对象,以常规施肥为对照(CK),设置增施750、1500、2250、3000、3750kg/hm^(2)(T_(1)~T_(5))5个牡蛎壳粉土壤调理剂用量水平,研究牡蛎壳粉土壤调理剂对土壤理化性质及茄子农艺性状和品质的影响,以期筛选其在茄子大田种植中的最佳施用量。结果表明,牡蛎壳粉土壤调理剂能够提高茄子叶绿素含量和株高,促进茄子果实发育,其中T_(4)处理表现最好,茄子叶绿素含量(现蕾期)、株高(现蕾期)、单果重、果实纵径都显著高于CK,较CK分别提高3.25%、7.24%、8.50%、5.75%,对茄子果实品质有一定的提升,茄子钙含量较CK提高2.3%~13.7%。增施牡蛎壳粉土壤调理剂能够降低土粒密度,提高土壤中氮和钾元素含量,提高土壤速效养分含量,碱解氮和速效钾含量较CK最高分别提高6.98%(T_(5))和42.39%(T_(4))。主成分分析表明,牡蛎壳粉土壤调理剂3000 kg/hm^(2)是茄子大田生产中的最佳选择。

Fully Recycled Syntheses Using Recycled Concrete Powder, Oyster Shell and Wood Powder: Effect of Combined Ground Treatment on Mechanical Strength and FTIR, XRD, and SEM Characterization

The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from oyster shell farming. However, there is a lack of evidence on the possibility of producing a fully recycled composite consisting of recycled concrete and oyster shell without the need for new cement and natural aggregates. In this study, recycled concrete powder (RCP) and oyster shell were used to produce a green composite. Separate ground and combined ground (separate ground and co-ground) RCP and oyster shells are used to determine the effects of grinding approaches on the mechanical and chemical properties of the composite. The composite samples were molded via press molding by applying 30 MPa of pressure for 10 minutes. The results revealed that the composite prepared via the combined ground approach presented the highest flexural strength compared to the separate ground and unground samples. The FTIR and XRD characterization results revealed no chemical or phase alterations in the raw materials or the resulting composites before and after grinding. SEM analysis revealed that combined grinding reduced the particles’ size and improved the dispersion of the mixture, thereby increasing the strength.

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。

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。

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。

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。

贝壳粉对豆渣厌氧发酵的影响研究

豆渣作为一种有机废弃物,其含有较高的化学需氧量,随意排放会产生恶臭,滋生蚊蝇。我国贝壳数量庞大,价格低廉,将生蚝贝壳研磨成的粉末作为豆渣厌氧发酵的添加剂这一应用具有广阔前景。本研究设计四组实验,同时向豆渣与活性污泥接种质量比例为2∶3的底物中分别添加0,2.0,4.0和8.0 g的生蚝贝壳粉并记为T_(1)、T_(2)、T_(3)和T_(4),并对发酵体系pH值、电导率(EC)、化学需氧量(COD)、气体成分及含量和挥发性脂肪酸(VFAs)等指标进行研究。结果表明,产甲烷能力最好的是生蚝贝壳粉添加量为8.0 g的T_(4),其间共产生甲烷气体371.2 L/kg VS added,其次分别是T_(3)、T_(2)、T_(1)。研究证明在豆渣厌氧发酵过程中,添加生蚝贝壳粉可有效维持厌氧体系pH值、加快厌氧发酵进程、促进厌氧发酵顺利进行。

高岭土-牡蛎壳粉改性材料的制备及其对海水、淡水中氨氮与磷酸盐的去除效果

为实现水中磷酸盐、氨氮的吸附去除,将牡蛎壳粉和高岭土以质量比3∶1比例混合,在不同条件(MgO添加量:0%、2%、4%、8%、12%;温度:0、600、700、800、900、1000℃)下制备并筛选出吸附效果最佳的改性牡蛎壳粉,通过扫描电镜、傅里叶红外光谱仪、比表面与孔隙度分析仪和X射线衍射仪对改性牡蛎壳粉进行表征。采用动力学模型和等温吸附模型拟合吸附过程,并分析初始pH、吸附柱对改性牡蛎壳粉、磷酸盐和氨氮吸附的影响。结果表明:MgO添加量为8%,煅烧温度为800℃时,改性牡蛎壳粉吸附性能最佳,对磷酸盐的去除率分别为91.7%(海水)和82.25%(淡水),对氨氮的去除率分别为36.67%和47.71%;改性牡蛎壳粉对磷酸盐的吸附符合准二级动力学模型和Freundlich模型,最大磷酸盐吸附量分别为108.37(海水)、101.99(淡水)mg/g,对氨氮的吸附符合Langmuir模型,最大氨氮吸附量分别为0.27(海水)、0.38(淡水)mg/g;酸性条件有助于磷酸盐的吸附,中性条件则更利于氨氮的吸附;在吸附柱中改性牡蛎壳粉对氨氮和磷酸盐的吸附量分别为0.12、78.95 mg/g(海水)和0.17、70.34 mg/g(淡水);应用其处理入海口污水中磷酸盐和氨氮,去除率分别为96.83%、9.7%,出水达到Ⅰ类水标准。研究表明,改性牡蛎壳粉成本低,具有高效去除水中磷酸盐和氨氮的应用潜力。

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。