Understanding competitive adsorption between phosphate and selenite at iron oxide interfaces is essential for predicting selenium retention and mobility in phosphate-affected soils and sediments. This study investigated their competitive adsorption on ferrihydrite using batch experiments, time-resolved Fourier transform infrared spectroscopy coupled with two-dimensional correlation spectroscopy (2D-COS), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations. Increasing the initial P(V) concentration from 0 to 500mg/L decreased the equilibrium Se(IV) adsorption capacity from 39.82 to 13.72mg/g and reduced the uptake rate. This inhibitory effect persisted at a lower initial Se(IV) concentration of 50μg/L. Se(IV) retention decreased markedly with increasing pH, whereas P(V) adsorption showed weaker pH dependence. Time-resolved 2D-COS showed that the phosphate-associated spectral response preceded the selenite-associated response, indicating earlier development of phosphate-related interfacial changes. XPS showed that the normalized surface atomic fraction of Se decreased from 4.71% to 1.57% in the presence of phosphate, whereas the corresponding P fraction decreased only from 10.87% to 9.40%. Representative DFT configurations yielded adsorption energies of -1.83eV for H2PO4- and -1.27eV for HSeO3-, supporting a stronger binding tendency for phosphate. Overall, phosphate suppressed selenite retention through earlier interfacial responses, preferential competition for reactive surface sites, and stronger relative binding. These findings suggest that phosphate inputs may increase dissolved Se availability in phosphate-affected environments.

Colloids can potentially affect the efficacy of traditional acid mine drainage (AMD) treatment methods such as precipitation and filtration. However, it is unclear how colloids affect antimony (Sb) migration in AMD, especially when natural organic matter (NOM) is present. To conduct an in-depth investigation on the formation and migration behavior of NOM, iron (Fe), Sb and NOM-Fe-Sb colloids in AMD, experiments were performed under simulated AMD conditions. The results demonstrate significant variations in the formation of NOM-Fe-Sb colloids (1-3-450 nm) as the molar ratio of carbon to iron (C/Fe) increases within acidic conditions (pH = 3). Increasing the C/Fe molar ratio from 0.1 to 1.2 resulted in a decrease in colloid formation but an increase in particulate fraction. The distribution of colloidal Sb, Sb(III), and Fe(III) within the NOM-Fe-Sb colloids decreased from 68 % to 55 %, 72 % to 57 %, and 68 % to 55 %, respectively. Their distribution in the particulate fraction increased from 28 % to 42 %, 21 % to 34 %, and 8 % to 27 %. XRD, FTIR, and SEM-EDS analyses demonstrated that NOM facilitates the formation and crystallization of Fe3O4 and FeSbO4 crystalline phases. The formation of the colloids depended on pH. Our results indicate that NOM-Fe-Sb colloids can form when the pH <= 4, and the proportion of colloidal Sb fraction within the NOM-Fe-Sb colloids increased from 9 % to a maximum of 73 %. Column ex- periments show that the concentration of NOM-Fe-Sb colloids reaches its peak and remains stable at approxi- mately 3.5 pore volumes (PVs), facilitating the migration of Sb in the porous media. At pH >= 5, stable NOM-Fe-Sb colloids do not form, and the proportion of colloidal Sb fraction decreases from 7 % to 0 %. This implies that as pH increases, the electrostatic repulsion between colloidal particles weakens, resulting in a reduction in the colloidal fraction and an increase in the particulate fraction. At higher pH values (pH >= 5), the repulsive forces between colloidal particles nearly disappear, promoting particle aggregation. The findings of this study provide important scientific evidence for understanding the migration behavior of NOM-Fe-Sb colloids in AMD. As the pH gradually shifts from acidic to near -neutral pH during the remediation process of AMD, these results could be applied to develop new strategies for this purpose.

The reaction mechanisms Fe(II) abiotic oxidation produce ·OH by CaCO3-induced in acid mine drainage (AMD) are well-documented, but little is known about the influence of extracellular polymeric substances (EPS) secreted by microorganisms on Fe(II) oxidation in AMD. In this study, ·OH production was experimently measured from oxygenation of simulated AMD in the presence of EPS. The cumulative ·OH increased from 56.75 to 158.70 µM within 24 h at pH 3 with the increase in EPS concentration from 0 to 12 mg/L. An appropriate pH (about 6) and EPS (6 mg/L) concentration were required for the moderate rate of Fe(II) oxidation. Besides, the yield of ·OH increased remarkably with the addition of Fe3+. In the presence of EPS, ·OH production is attributed mainly the complexation of Fe(II) with EPS, of which is rich of carboxyl and hydroxyl groups. The findings provide fundamental supplement of ·OH production from Fe(II) oxidation by microorganisms in natural AMD.

The high concentration Fe3+ in sample had interference on the determination of iron species by spectrophotometric method in which 1,10-phenanthroline was used to as a chromogenic agent. The F− could mask absolutely the effect of Fe3+ when F−/Fe3+ molar concentration ratio was 13.3. The temperature or light did not affect the masking action of F−. Low temperature and dark conditions favored the stability of chromophoric complex. This method is suitable for the measure of iron species where the concentration of Fe3+ is far more than that of Fe2+ in samples.

The high concentration of ferric (Fe 3+ ) in sample has interference on the determination of ferrous(Fe 2+ ) concentration by spectrophotometric method which 1, 10-phenanthroline is used to as chromogenic agent.Appropriate concentration of fluorine ion (F -) can complex Fe 3+ to eliminate interferences which the F -concentration is 13.3 time greater than that of Fe 3+ .The temperature and light do not affect the masking action of F -. Low temperature and dark conditions favour the stability of chromophoric complex.This method is suitable for determination iron species in the presence of high concentration of Fe 3+ in sample.

Using nutrient solution culture method, the effects of Cu2+on seed germination, seeding growth of Otte-lia acuminatas were studied.The results showed that effect of exogenous Cu2+within the concentration varied from 0.1 to 10 mg/L on seed germination rate of Ottelia acuminatas showed no significant difference compared with con-trol ( p>0.05 ) , while for the inhabitation of germination potential , germination index and vital index , there was significant difference compared with control ( p<0.05 ) in higher concentration .Cu2+had an inhibitory effect on chlorophyll and carotinoid content of Ottelia acuminatas, and there was significant difference compared with control (p<0.05 ).With increasing concentration of Cu2+, the activities of superoxide dismutase ( SOD), peroxidase ( POD) , soluble protein contents of seedling showed increasing at beginning and then decreasing; At the same time, the activity of catalase (CAT) was consistently decreasing, and there was significant difference compared with control ( p<0.05 ) . This study could provide certain theoretical support for the natural Ottelia acuminatas conservation .

通过营养液培养法，研究Cd2＋对海菜花种子萌发及幼苗初期叶绿素含量、抗氧化酶活性及可溶性蛋白质含量的影响。结果表明，各浓度（0．1～2．0 mg／L）Cd2＋处理抑制海菜花种子的萌发，但与对照无显著差异（P＞0．05）；海菜花种子的发芽势、发芽指数、活力指数整体随Cd2＋处理浓度的增大而下降，当Cd2＋处理浓度较高时，与对照差异显著（P＜0．05）。 Cd2＋胁迫明显降低海菜花叶片中叶绿素a、叶绿素b、类胡萝卜素含量，且与对照差异显著（P＜0．05）。随着Cd2＋浓度增大，超氧化物歧化酶（ SOD）活性、过氧化物酶（ POD）活性、可溶性蛋白质含量先升高后降低；过氧化氢酶（CAT）活性呈持续降低趋势，且与对照差异显著（P＜0．05）。随Cd2＋胁迫浓度增大，其对海菜花的毒害作用增强。

选择土霉素为模式药物,研究了不同浓度的外源溶解性有机物质(有机肥、腐殖酸、L-苹果酸)对黄壤中土霉素降解的影响.结果表明,在加入有机肥、腐殖酸和L-苹果酸后,无论黄壤是否灭菌,土霉素在黄壤中的降解速率都显著提高,半衰期明显缩短,并且其降解动态均符合一级动力学方程.

Effects of Cu2+ on physiological and biochemical indices of Ottelia acuminatas were studied by means of nutrient solution culture. The exogenous Cu2+ with varieties of concentrations (0. 01 mg/L, 0. 05 mg/L, 0. 10 mg/L, 0. 20 mg/L and 0. 40 mg/L) exhibited inhibitory effects on chlorophyll contents and carotinoid content in O. acuminatas leaves. The activities of superoxide dismutase(SOD),peroxidase(POD), soluble protein and leaf Cu2+ contents showed an "in-crease-first-and-deerease-afterwards" response to the increase of exogenous Cu2+concentration, however, the activity of cat-alase( CAT) was continuously decreasing, indicative of intolerance of O. acuminatas to copper stress.

为准确测定黄壤中土霉素残留量,建立固相萃取-高效液相色谱法提取以及测定黄壤中土霉素残留量.通过对提取缓冲液、流动相比例以及流速等测定条件研究,HPLC测定结果表明,提取液为Na2EDTA-Mcllvaine,流动相为乙腈:1/1 000甲酸(V:V=15:85),温度为25℃,流速为1.0 mL· min-1,紫外检测波长为350 nm是测定黄壤中土霉素残留量最适宜方法.相关系数(n=18)为0.997;检出限为0.09mg·kg-1;回收率(n=18)为88.1％～95.3％;相对标准偏差(RSD,n=18)为3.3％～11.7％.

Antibiotics, especially tetracyclines (TCs) are widely used in agriculture in world. The adverse effects of TCs contaminants on non-targets organisms have generated an interest in the fate of TCs in soil environment. In order to illustrate the effects of soil temperature on degradation of TCs such as oxytetracycline (OTC) in soils, the degradation of OTC in three soils including fluvo-aquic soil, black soil and red soil were investigated at the temperature of 5 degrees C, 15 degrees C, 25 degrees C respectively. The contents of OTC in three soils decreased gradually with time. The degradation rate of OTC was higher at 25 degrees C than at 5 degrees Cand 15 degrees C. The degradation curve of OTC in three soils could be described by the first-order kinetic model and the correlation coefficients ranged from 0.8895 to 0.9922. Under the same conditions, OTC degradation rate was higher at the initial added level of 20 mg kg(-1) than that at the initial added level of 200 mg kg(-1). The differences in degradation of OTC in three soils were also observed. OTC degradation in fluvo-aquic soil is faster than that in the other two soils.

Wave dissipation for perforated-breakwater has been investigated in this paper.The relationships of wave transmissivity and reflectivity among the constructed width,the wave steepness and the slope are carefully studied by physical simulation.The results of tests indicate that the perforated-breakwater with 1.2Hm and slope for 1:1.5 has the good characteristics of dissipating waves.

Traditionally,we regarded the management object related to ocean as the standard to set up governmental departments and divide its functions,but now this practice needs to be changed.It is essential that when discussing the modern government's functions in the marine management,we should understand it from the perspective of protecting civil rights,offering public services and improving public welfare.The basic responsibility of national marine management is to provide marine public goods,including safeguarding the marine rights and interests,maintaining the marine activity order,supplying the marine public goods,exploiting the marine resources and protecting the marine environment and so on.Therefore,the reform of marine administrative management system in China should play down the views of "resource management" or "marine program";meanwhile,we should understand exactly the prevalent opinions like "integrated management",get rid of the narrow departmental view,look at the governmental functions in marine management from the duty of marine management and adjust the set-up of governmental departments and its function allocation in the light of the actual conditions.

By using the normal wave model,this paper studies the cross-section profile of the Beidaihe beach with or without the shore nourishment through the measurements of limit wave height at three kinds of water levels,and the wave height inside and outside the bar and stable terrain of beach strand.The analysis data shows that the wave transmission coefficient decreases with the water level dropping.The sediment carrying capacity of littoral current weakens enough so that sediment may deposit in the lee of artificial bar.To a certain extent,the shore nourishment can prevent the loss of sediment offshore.The research result can provide scientific data for the design and implementation of the engineering for protecting the beach and promoting the silt.

Owing to the complexity of the dynamic environment of seabed,the problem has manifested itself in the destruction of submarine pipelines,and the erosion of sea bed is one of the reasons.After theoretical analysis and experimental study on the angle of repose of scour pit under the action of unidirectional flow in this work,the correlativity and variation law was found which has the reference value for further research in the protective technology of submarine pipeline.

Submarine pipeline is one of most important parts of the ocean oil field exploitation system,which can be damaged by the very complex ocean environment. To make the pipeline self-burying, thispaper proposes to use flexible spoiler instead of rigid spoiler attached on the top of the pipeline, which cannot only increase the scour depth and range, but also abate both turbulence intensity the rigid spoiler actson the flow above the pipe and wake flow vortex so as to decrease vibration of the pipe. The quadraticcurved surface equation of deformed flexible spoiler and deflection of free end formula are deduced on thebasis of dynamical relation under the conditions of both interstice ratio is zero and is not zero. A series ofexperiments has been conducted under unidirectional current in which different material and length of flex-ible spoilers were installed on the top of the pipeline and the deformation of flexible spoilers is measured.By comparing the maximum deflection of free end and deformation of curved surface calculated by formu-las with the data measured from experiments, find the two values are very close to each other. Thereforethe formulas can be used to calculate the deformation of flexible spoiler attached on top of the pipeline ap-proximately.

In order to study the local scour around the horizontal cylinder near sand bed,a 2-d numerical model of local scour based on N-S equations and finite volume method is established through the redevelopment in FLUENT code.Firstly,the flow field around the horizontal cylinder is calculated by using standard k-eequations,and the bed-load transport rate is computed by the selected empirical formula related to the bed shear stress via UDF(user defined function).Then,the bed profile is simulated by means of dynamic mesh.The model is verified by the physical experiment.The results show that the predictions agree well with the experimental results,which certifies the numerical model's reliability.

According to the characteristics of flow around the submarine pipeline,using the method which is used to analyze jets,the velocity profiles in the free shear region are obtained through properly simplifying the governing equations.A systematic experimental research on the characteristics of the flow velocity field around the submarine pipelines is conducted by ADV and the rules of velocity and turbulent intensity changes in different flow areas are also investigated.The measure results agree well with the theoretical analysis.These results make a theoretic foundation for the further research on protection technique of submarine pipelines.

In order to study the characteristics of flow around the submarine pipeline with spoiler,a novel method using experiment and numerical simulation is proposed in this paper.The numerical model is discredited by finite volume method and selects standard k e turbulence model.By contrastive analysis,the numerical results agree well with the experimental results.In addition,the spoiler's influences on the stagnation point of upstream,velocity field,pressure distribution of pipeline,drag coefficient,lift coefficient,and the seabed shear stress at various gap ratios are investigated.These results might be useful for further study of submarine pipeline erosion and protection.

In order to investigate the effects of plastic film mulching(PFM) on maize growth and phosphorus uptake,effects of PFM were studied on dry mass accumulation,phosphorus content,phosphorus uptake,phosphorus distribution,and phosphorus harvest index of corn receiving different fertilizers in field condition.The results were presented as follows: 1) PFM could significantly increase the dry mass of corn at different growth stage.The largest percentage of dry mass occurred at seedling and jointing stages of corn with the values of 24.9%-126.3%.At the seedling stage,dry mass of corn was more strongly increased by PFM,with the application of just phosphorus fertilizer than with the application of phosphorus and potassium,or nitrogen,and potassium fertilizers at the same time.2) PFM could also significantly increase the phosphorus content,phosphorus accumulation of above part of corn,and its effect is stronger at the early growth stage of corn than that at the late growth stage.At the presence of PFM,the content of phosphorus,and accumulation of phosphorus of corn are higher at the treatment of P than those at other treatments such as CK,PK,and NPK.The content of phosphorus and accumulation of phosphorus of corn were increased by 56.3% and 253.0%,respectively,at the treatment of phosphorus fertilizer and PFM.PFM has no significant effects on phosphorus transferring rate of corn.