STUDY ON THE ISOTHERMS OF THE INTERACTION BETWEEN SUSPENDED PARTICLES AND Cu (Ⅱ) IN THE HUANGHE RIVER

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PLATEAU TYPE E(%)-pH CURVES OF INTERFACIAL EXCHANGE BETWEEN LIQUID AND SOLID IN SEAWATER

A study on the curves of the exchange ratio E(%)-pH on the liquid-solid interface of the systems Zn(II) with clay minerals (Kaolinite , illite and montmorillonite), Zn(II) with hydrous ferric oxides (amorphous ferric oxide, goethite and hematite). Zn(II) with hydrous manganese oxide (y-MnOOH, manganite and 5-MnO2) etc . in seawater resulted in the discovery of new plateau type exchange ratio ?%)-pH curves not yet reported in literature. The two factors that decide the growth , decline and the change of the " plateau type " curve are : (1) the inherent characteristics of systems , which can be explained by the exchange constants i(i=1 ,2 , 3 . etc .) of interfacial stepwise ion / coordination particle exchange between liquid and solid ; and (2)The theory of interfacial stepwise ion/coordination(the amount of solid exchange reagent)particle exchange in seawater was applied to explain the experimental results of the above study and a general formula was derived for the plateau type exchange ratio E(%)-pH c     

Plateau typeE(%)- pH curves of interfacial exchange between liquid and solid in seawater

A study on the curves of the exchange ratioE(%)- pH on the liquid-solid interface of the systems Zn (II) with clay minerals, (Kaolinite, illite and montmorillonite), Zn (II) with hydrous ferric oxides (amorphous ferric oxide, geothite and hematite), Zn (II) with hydrous manganese oxide (γ-MnOOH, manganite and δ-MnO₂) etc. in seawater resulted in the discovery of new plateau type exchange ratioE(%)-pH curves not yet reported in literature. The two factors that decide the growth, decline and the change of the “plateau type” curve are: (1) the inherent characteristics of systems, which can be explained by the exchange constants (i=1, 2, 3, etc.) of interfacial stepwise ion/coordination particle exchange between liquid and solid; and (2) . The theory of interfacial stepwise ion/coordination particle exchange in seawater was applied to explain the experimental results of the above study and a general formula was derived for the plateau type exchange ratioE(%)-pH curves. The theoretically simulated and calculated curves coincided well with the experimental results. This paper provides new and powerful experimental basis to support the theory of interfacial stepwise ion/coordination particle exchange in seawater. The project was supported by the National Natural Science Foundation of China.     

Fourier-transform infrared spectroscopic studies on the interaction among marine trace metal ions,solid particles and organics

IR spectra of Cu (II)-marine solid particle systems show that Cu(II)-marine solid particle ion exchange causes a stepwise change in the surface H-bonding hydroxyl groups on illite, montmorillonite, CaCO₃, γ-AlOOH and goethite, but that this does not affect the surface free hydroxyl groups on illite, montmorillonite and CaCO₃, and framework hydroxyl group on goethite and on γ-AlOOH. Over the range of Cu (II) exchange amounts in the present experiment, four stepwise changes were discovered for the surface H-bonding hydroxyl group on illite, while two stepwise changes were observed on the other marine solids. The interfacial stepwise ion exchange theory was first demonstrated by the above experimental evidence.     

Study on the isotherms of the interaction between suspended particles and Cu (II) in the Huanghe River

The isotherms of the interaction between the suspended particles and Cu²⁺, and the effects of lysine and asparaginic acid on the isotherms in the Huanghe (Yellow) River were studied by applying the theory and method of interfacial stepwise ion/coordination particle exchange. We obtained a new stepped river isotherm, formed by two curves joined together with a “plateau” in the middle. The adsorption equilibrium constantsK ₁ andK ₂ were calculated by using the isothermal equation of surface stepwise ion exchange. Amino acid in small amount promotes exchange adsorption of the suspended particles with Cu²⁺. The degree of promotive action relates to the isoelectric point of amino acid. The promotive effect of lysine is bigger than that of asparaginic acid. Project 29361001 supported by NSFC.     

The effect of amino acids on copper (II)-goethite ion exchange in seawater

In seawater, aside from metal elements and suspended particles, organic substances amount to about 500–2,000 ug carbon/l^[8], which is not neglegible in comparison with that of minor metal elements. But in the study of the interaction of the three constituents (metal elements, organics, and suspended particles), the effect of organics in seawater on the surface reaction of metal element—suspended particles has usually been neglected. Recent theoretical research^{[1, 11]} confirmed the importance of the effect of organics in seawater on the surface reaction of metal element—suspended particles. Generally, the effect of organics on the reaction of metal ions, especially Cu(II), on a solid surface is either promotive^[2] or inhibitive^{[7, 9]}. So far the fact that organics cannot affect the surface reaction of Cu(II) ions on solids has not been reported in literature. Our experimental results showed that none of the amino acids in seawater affect Cu(II)-goethite ion exchange under certain experimental condition (such as amino acid of lower concentration and lower pH). It was known that the metal ion-organics complex in a liquid competing with solids for metal ions may inhibit the surface reaction of metal ions on solids, but the mechanism of the complex reaction of metal ions competing with solids is not known yet. In fact, the decrease of surface site-exchanging due to the surface reaction of organics on solids is also inhibitive. It is also explained by the ion exchange isotherm of the “amino acid-Cu(II)-geothite” system. This result further demonstrates that the theory of interfacial stepwise ion exchange is applicable to the metal ion exchange isotherm with the presence of organic substances in the system. Projects supported by the Science Fund of the Chinese Academy of Sciences     

The distribution and variation of elements in sediments off the Huanghe (Yellow) River mouth

Surface sediment samples collected off the Huanghe (Yellow) River mouth during the period 2007–2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray fluorescence spectrometry. Results demonstrate that sediment grain size is the dominant factor controlling the spatial variations of elemental concentrations. Correlation and cluster analyses allowed classification of the study area into four geochemical regions: Regions I and III are characterized by high concentrations of Al₂O₃, Fe₂O₃, MgO, Na₂O, K₂O, Cr, Cu, Mn, Ni, Pb, V, and Zn, and contain fine-grained sediments with mean grain size (M _z)<22 μm; and; Regions II and IV contain mostly coarse-grained sediments, and are characterized by high concentrations of SiO₂, Na₂O, and Zr. The sediment entering the sea from the Huanghe River and its tributaries is enriched in Ca. Thus, the Ca/Al ratio was used as an indicator of the proportion of sediments in the study area that originated from the Huanghe River. Ca/Al ratios decrease from Regions I and II (located in the nearshore zone of the Huanghe River delta) to Regions III and IV (distributed in the offshore zone of the northern Huanghe River delta, southern and southeastern Laizhou Bay area).     

Geochemical Characteristics and Sources of Some Chemical Components in Sediments of Zhuiiang（Pearl） River Estuary

Sediment cores with length of 25 - 45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al2O3 , Fe2O3, CaO, TiO2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and grain sizes were analyzed. Sediments in Zhujiang River Estuary are characterized by relatively coarse grain size. The grain sizes of the sediments in the area outside the estuary are relatively finer than those in the north part of the estuary but coarser than those in the middle of Lingdingyang and have a trend similar to the spatial distribution trend of some chemical components such as Fe2O3, Al2O3, TiO2, V, Cu, Ni, Zn and Y. This showed that grain size is an important factor that controls the spatial distribution and depth profile of chemical elements in the Zhujiang River Estuary. Frequent re-suspension, re-transportation and redistribution of settled sediment on estuary floor could be deduced from the spatial distributions and depth profiles of chemical components. Except for CaO and Sr, the chemical components always enrich at the west side of, in the middle of, and at the north side of, the estuary. Fe2O3, Al2O3, Ti, V, Cr, Ni, Zn, Cu and Y in Zhujiang River Estuary sediments mainly result from rock and soil weathering except that parts of Cr, Ni, Zn Cu and Y are anthropogenic. CaO and Sr in sediments originate from marine source. Although Co as well as Pb derives from anthropogenic sources, human activities related to Co might differ from the activities related to Pb.     

The surface reaction on liquid-solid interface of “amino acid-Cu(II)−MnO2” system in seawater

The results obtained from the Cu(II)%-pH curve of the system in the presence of added amino acid indicated that the added amino acids of higher concentration can inhibit the Cu(II)-σ-MnO₂ ion exchange and that their inhibiting effects decrease in the following sequence when the initial amino acid concentrations are 20.00 ppm: histidine > cystine > glutamic acid > proline > alanine > glycine. The determination of amino acid in solution performed with an amino acid analyser showed that added amino acids react chemically on the surface of the σ-MnO₂ According to thermodynamic equilibria relations in the system, amino acids can be changed to amines because of their decarboxylation on the surface of the σ-MnO₂. Considering (1) the effect-inhibiting factor of amine F_A(β, K_a, pH) representing the complex potential of amine with Cu(II) in solution and (2) the acidic constant of −NH ₃ ⁺ group in the amine molecule representing the ability of cation exchange of the amine with σ-MnO₂, the inhibiting seqence of added amino acid of 20.00 ppm (Eq.(1)) is reasonable. Thus added amino acids do inhibit Cu(II)-σ-MnO₂ ion exchange because (1) the amino acid and/ or amine, which is the decarboxylate of the corresponding amino acid, complex with Cu(II) in solution and compete with σ-MnO₂ for Cu(II); (2) the cation exchange of the amino acid and/or amine reduce the exchange site on the surface of the σ-MnO₂. The results obtained from the isotherms indicated that the theory of interfacial stepwise ion exchange can be extended to the Cu(II) σ-MnO₂ ion exchange system in the presence of added amino acid.     

DISTRIBUTIONS OF TOTAL, INORGANIC AND ORGANIC PHOSPHORUS IN THE SEDIMENTS NEAR THE HUANGHE RIVER ESTUARY

For some hundred surface sediment samples from five cores taken in two cruises near the Huanghe River Estuary, total phosphorus (TP (.inorganic phosphorus (IP (and organic phosphorus (OP)were determined.On the average, 527×10-6, 455×10~6 and 72×10-6 were found for TP,IP and OP for the surface sediments taken in the two cruises. The distribution of OP and IP was controlled by the sample particle size: OP content increased with the decreasing of the sample particle size, while the maximal value of IP was found in the silt fraction due to the existence of apatite in our samples. Vertical distributions reflected well the channel change of the Huanghe River. Results from the multiple regressions between the three forms of phosphorus and the percentages of different particle size agreed well with the analytical data.     

Morphodynamic evolution of the Xiaoqing River mouth: a Huanghe River-derived mixed energy estuary

In an estuary,tidal,wave and other marine powers interact with the coast in different ways and affect estuary morphology as well as its evolution.In the Huanghe(Yellow) River estuaries and nearby delta,there are many small sediment-affected estuaries with a unique morphology,such as the Xiaoqing River estuary.In this study,we investigated the special evolution and genetic mechanism of the Xiaoqing River estuary by analyzing graphic and image data with a numerical simulation method.The results show that NE and NE-E tide waves are the main driving force for sandbar formation.Sediment shoals have originated from huge amounts of sediment from the Huanghe River,with consequent deposition at the Xiaoqing River mouth.The lateral suspended sediments beyond the river mouth move landward.Siltation takes place on the northern shoreline near the river mouth whereas erosion occurs in the south.The deposits come mainly from scouring of the shallow seabed on the northern side of the estuary.Storm surges speed up deposition in the estuary.Development of the sediment shoals has occurred in two steps involving the processes of growth and further southward extension.Although the southward shift increases the river curvature and length,the general eastward orientation of the estuary is unlikely to change.Processes on the adjacent shorelines do not affect the development of the sediment shoals.The study presents a morphodynamic evolutionary model for the Xiaoqing River estuary,with a long-term series cycle,within which a relatively short cycle occurs.     

APPLICATION OF REMOTE SENSING AND FUZZY MATH TO STUDY OF SUSPENDED SEDIMENTS DIFFUSION NEAR THE HUANGHE RIVER DELTA

Sediment grain size parameters and the percent of sand and clay near the Huanghe River Delta are used to estimate the Huanghe Riser load diffusion with fuzzy analysis. The results are confirmed by field investigation and the landform changes of the river estuary and sediment diffusive pattern indicated by Landsat MSS, TM images.     

Spatial variations in depth-distribution of trace metals in coastal wetland sediments from Quanzhou Bay, Fujian Province, China

Four short cores were obtained from the coastal wetland of the Quanzhou Bay, Fujian Province, China, and sediment samples were analyzed with a Mastersizer 2000 for grain size analysis and an Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) for trace metal analysis. The results of grain size analysis show that the wetland sediments are mainly composed of silt and clay, and the distribution of median grain size is affected by human activities obviously. The results of trace metal analysis show that the wetland sediments mainly originate from terrestrial materials in the Luoyangjiang River estuary and from contaminants discharged from adjacent rivers in Shuitou area. The heavy metal contamination in Luoyangjiang estuary decreased from 1984 to 2004 due to industry transformation, but has increased since 2004 because of the discharge of contaminants to the Jinjiang River and much living sewerage to the bay, and a large number of trace metals are trapped within Spartina alterniflora marsh.     

GEOCHEMICAL CHARACTERISTICS OF SEDIMENTS AND ANALYSIS OF THE CHANGJIANG ESTUARY ENVIRONMENT

Analysis of material from three 55- cm long cores collected with box corer m summer of 1988 in the Changjiang Estuary region yielded data on the sedimentation rate, granulometric composition and contents of carbonates, organic matter, Al, Fe, Mn, Zn, Cu and Pb there. Subsequent study of the data led to the conclusion that there is no obvious pollution in the region based on the absolute value of the content of heavy metals, but the region is in potential danger of being polluted as seen by the obvious increase of sedimentation flux of heavy metals to and the enrichment of them on the surface sediment during the last several years, e.g. Pb increased by 10-20μg/g, Zn by about 30μg/g, Cu by 5-10μg/g and Mn by 150μg/g.A ferromanganese redox interface was found at about 40 cm depth of sediments where Fe and Mn and associated trace metals are enriched. The trace metals such as Zn, Cu have (but Pb does not) the same source, forms, displacement mechanism and geochemical behaviours as those of Fe and Mn in t     

Evaluation of the Bioavailability of Metals in Sediment from the Southern Coastal Wetland of the Qiantang Estuary by Using Diffusive Gradients in Thin Films Technique

Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.     

THE REMOVAL OF Zn,Cd,Pb,AND Cu IN THE CHANGJIANG ESTUARY

The waters with salinity from 10 to 23 comprise the main removal region of ion and particulateforms of heavy metals in the Changjiang estuary.The positive correlationships between Zn,Cd,Pb,Cuand the reciprocal of transparency,COD and chlorophyll-a showed that the removal of heavy metalsclosely correlate with the distribution of suspensions,the adsorption of organic materials and theassimilation by organisms.The removal of heavy metals in the Changjiang estuary water were consistentwith the sedimentation rate of the sediments in these waters,sediment types and the distributions ofheavy metals contents in the sediments.     

Changes in Huanghe （Yellow） River estuary since artificial re-routing in 1996

With the combination of historical data, field observations and satellite remotely sensed images(Landsat TM/ETM and CBERS), changes in Huanghe (Yellow) River estuary since 1996 when artificial Chahe distributary was built up were studied, mainly including water and sediment discharge from the river, tides, tidal currents, suspended sediment diffusion, coastline changes and seabed development. During following six and half years (up to the end of 2002), runoff and sediment loads into the river mouth declined dramatically. At the beginning of the re-routing, abundant sediment loads from the river filled up nearshore shallow water areas so that the newborn delta prograded quickly. With rapid decrease of sediment loads transported to the estuary, the delta retrograded. In 1997, subaerial tip of the abandoned delta receded 1.5km; its annual mean recession rate was about 150 m in following years. In addition, marine dynamic condition near the artificial outlet had also changed. Under the interaction of ocean and river flow, most of incoming sediment loads deposited in the vicinity of the outlet. Seabed erosion occurred at the subaqueous delta front. Between 1999 and 2002, erosion thickness averaged at 0.3 m in the subaqueous delta of 585.5 km2.     

THE INTRINSIC ACIDITY CONSTANTS AND SPECIFIC SURFACE AREA OF MARINE SOLID PARTICLESII. THE RELATIONSHIP BETWEEN THE INTRINSIC ACIDITY CONSTANT AND THE TERNARY SURFACE COMPLEX

This paper deals with the infrared spectra of " amino acid- clay , calcium carbonate and y-AlOOH" and " Cu (II )-clay-amino acid" model systems, and shows that the model of the ternary surface complex is M-OHLCu (L = amino acid) for marine solid particle-Cu (II)-amino acid. Study of the formation mechanism of the ternary surface complex shows that the specific surface area , and especially the intrinsic acidity constant, determine whether the ternary surface complex is easily formed, and that factor, FTSC,quantifies the relationship between the promoting effect of organics on Mt-marine solid particle ion exchange and the intrinsic acidity constant and specific surface area.     

The origin,historical variations,and distribution of heavy metals in the Qiongzhou Strait and nearby marine areas

We analyzed heavy metal concentrations in a number of surface sediments and cores from the Qiongzhou Strait and surrounding marine areas.The areas of high concentrations are primarily outside the eastern mouth of the Qiongzhou Strait and on the west side of the Leizhou Peninsula,whereas the areas of low concentrations are located primarily in the eastern Qiongzhou Strait.The maximum Cd,Pb and Zn concentrations in the samples collected in our study do not exceed the official standards for marine sediments,whereas the concentrations of Cr and Cu slightly exceed the standards.Correlations exist between the concentrations of Cu,Pb,Zn,Cr and Cd,and the concentrations of these metals are positively correlated with the mean particle size(φ value),indicating that the finer sediments have adsorbed greater amounts of heavy metal elements than the coarser sediments.An evaluation of the potential environmental risks demonstrates that certain indices of heavy metal pollution and environmental risks are relatively low and may be assigned low risk levels,thereby indicating that,in terms of heavy metals,the marine sedimentary environment in this region is only mildly impacted.Our analysis of the contaminant origins shows that the heavy metals in this region primarily originate in the Pearl River Estuary and that a small amount of them is derived from local runoff.The elevated heavy metal concentrations from the upper sections of the cores started 130 years ago,which indicats that heavy metals in the surface sediments are primarily due to human activities associated with industrialization.     

DETERMINATION OF SEDIMENTARY RATE IN ESTUARY AND COAST BY ~(228)Th TECHNIQUE

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