Abstract:Natural self-purification, a potential mechanism in nature whereby mankind and the Earth are interrelated with each other, has been playing an increasingly important role in the field of harnessing contamination and remedying environment. Neverthelsss, the self-purification of natural minerals widely occurring in the inorganic world has been largely ignored. This means that only half of the potential self-purification capabilities offered by nature are recognized, exploited and utilized. Utilizing most of the natural self-purification functions of both the organic and the inorganic world is a reflection of implementation of the whole self-purification function. Pollutant treatment by natural minerals is based on the law of nature and reflects natural self-purification function in the inorganic world, similar to that of the organic world. The purification function of natural minerals for reducing pollutants is reflected mainly in the basic properties of environmental mineral materials. The basic properties of this function include surface adsorption, modified porous filtration, defects of crystal structure, ionic exchange, chemical activation, physical effect and micro-effect at nanometre levels as well as mineralogical-biological interactions. A series of case studies related to the natural self-purification, which were mostly completely by our group, are discussed in this paper. Mineralogical method and biological method are well matched in pollutants disposal and jointly constitute a natural system of self-purification in terms of pollution treatment and environmental remediation in the spheres of interaction between mankind and the earth surface.

Abstract:The interactions between minerals and microbes, which occur widely in nature and directly result in dissolution and formation of minerals, have profound impact on the environment. The interactions between minerals and microbes are helpful to remediation of the environment. The metal-reducing bacteria, for example, can degrade aromatic compounds like benzoate, benzene, toluene etc. through the oxidation process, or degrade (poly)nitroaromatic compounds and carbon tetrachloride through the reduction process by using Fe3 -oxide as the terminal electron acceptor. Microbes can cause some harmful elements such as U and Np to precipitate as insoluble mineral species through bacterial surface absorption or redox process. In addition, some microbes can actively oxidize sulphide minerals, resulting in the formation of acid mine drainage which is very hazardous to the environment.

Abstract:The surface reactions of sulfide minerals include surface oxidation, surface dissolution and surface adsorption. The release, adsorption and desorption of heavy metal elements from tailing are determined by the mechanism of the surface reactions of sulfide minerals. The contamination degree resulting from tailing is related to the surface reaction rate of sulfide minerals. Therefore, the studies of sulfide surface reactions are very important in the environmental evaluation and remediation of mines. This paper elaborates the research status of such sulfide surface reactions as reaction mechanism, surface structures, surface sites, reaction products and reaction rate, and deals with the progress of its application to mine environment. Some problems to be solved in the future study are also pointed out.

Abstract:The kinetics of interface reaction of environmental minerals is subjected to study the reaction rate of the toxic metal ions or hazard organic molecular on the mineral surfaces in earth surface environments and explore their interface reaction mechanism. On the mineral surfaces there exists a sort of functional groups that have very strong chemical activity. During the migration of the toxic metal ions or organic molecule on earth surface they would be reacted with the mineral surfaces and have different driving force and reaction rate for both of the surface functional groups and ions or molecule have different polarity, charge and Lewis acidity. These reactions process will forth control existing forms and stability of the toxic matter, as well as their migration and transformation in atmosphere, water system and sediments. This article gives a brief introduction about the kinetic theory of the interface reaction of environmental minerals and some application examples.

Abstract:In this paper, the recent advance in the study of the interactions between minerals and organic acids (both of small molecules and of large molecules) is presented. The stress is placed on the environmental significance and the mechanisms of the interactions at the interface between organic acids and minerals. The characteristics associated with the interactions and the difference in reactivity between small molecule organic acid and humic acid are discussed too. The interactions can control the transport, transformation and eventual fate of metals and organic contaminants as well as nutrient availability for biota. The interactions involve coexisting multiform mechanisms. The mechanisms are mainly affected by such factors as surface functional groups of organic acids and minerals, their content distribution, and the molecule mass and hydrophobic property of organic acids. The objective of this study is to raise the understanding of the interactions between minerals and organic acids as well as their environmental significance.

Abstract:In this paper, the seeping water and the sediments of the dam base in Fushui Reservoir, whose surrounding strata are mainly Silurian shale, were analyzed and investigated. The sediments are rich in Fe2O3 together with small amount of Al2O3 and SiO2. IR, XRD, SEM and TEM analyses show that crystalline minerals in the iron hydroxide sediments are mainly weakly-crystallized goethite with small amounts of illite and montmorillonite. There are some microtubular and spiral goethites scattered among the iron hydroxide colloidal cloud and submicrometer-size colloidal particles. The microtubular walls are found under TEM composed of nano-crystallines of goethite, and microspiral minerals are shown to have a resemblance to Gallionella bacteria in both morphology and size. It is obvious that they are closely related to microorganism mineralization.

Abstract:The contamination of water by arsenic might result from oxidation of arsenopyrite. In this paper, the oxidation and dissolution process of arsenopyrite was run under the action of acidic surface water in the temperature range of 15~45℃by using the mixed-flow reactor. The results show that the oxidation process of arsenopyrite is speeded up with increasing concentration of FeCl3solution and rising temperature of reaction within the temperature range of 15~35℃, whereas the reaction rate of arsenopyrite is reduced at 45℃, and that the arsenic released from the reaction of arsenopyrite with FeCl3acidic solutions whose concentration is lower than 1×10-4mol·kg-1is in the form of As(Ⅲ), which is likely to be soon oxidized into As(Ⅴ) in the FeCl3acidic solution.

Abstract:A study of the formation of goethite, hyrogoethite and hematite under the bacterial action indicates that the bacterial action includes the whole process of solution and adsorption, complexation, transformation and crystallization-nucleation. The action of bacteria on minerals is characterized by specialization. Bacterial action not only dissolves the original minerals and form new minerals but also produces the differences in microenvironments of organic chemistry, which can help to form new different minerals. This is called organic crystallization action. At the same time, bacterial action affects the crystalline structures and the surface properties of the minerals.

Abstract:Natural minerals are products of different sorts of evolution in nature. They possess abundant information of environmental changes in different times and spaces during the course of formation and transformation, and hence serve as information carriers of environmental changes. The research of environmental evolutionary laws indicated by natural minerals in loess layers, rivers, lakes, sea and atmosphere can recognize the relationship between environmental changes and micromorphology, microstructure, chemical composition, chemical property, geophysical property, genesis and paragenetic associations of minerals. Minerals can thus be used as information carriers.

Abstract:The authors chose magnetotactic bacteria of the loess-paleosol sequences of China as a target and made successive studies on magnetotactic bacteria in layers of Duanjiapo section, layers of Xifeng section as well as S5-1 layer in Luochuan section by such means as TEM, SEM, biochemical experiments, and organic geochemistry.The results show that they consist of membrane and cytoplasm as well as magnetosomes and gas balls arranged along long axes. Under the suitable conditions, a lot of magnetosomes grow in the magnetotactic bacteria. Magne- tosomes consist of Fe2O3·H2O, and can be discharged from the bacterial bodies to surrounding environment. This can change Fe2+to Fe3+and increase magnetic susceptibility in the layers, especially in the paleosol layers. The product of magnetotactic bacteria in the loess section of China is a function of temperature, humidity, pH value and content of iron at the surface. They are obviously different from magnetotactic bacteria in the lake and swamp in shape, quantity and arrangement of magnetosomes, and hence the magnetotactic bacteria in loessial re- gion of Northwest China constitute a typical ecological species.

Abstract:Components of atmospheric particles were studied by XFR, XRD, IR and SEM, and the results show that they are basically the same in different parts of Hefei City. Mineral components of atmospheric particulates include illite, gypsum, chlorite, quartz, feldspar, calcite, dolomite and noncrystalline substances. There are abundant Ca, Pb Co, Cu and Zn in the particulates. Analytical results demonstrate that atmospheric particulates come mainly from concrete industry and traffic, and partly from air dust and soot of industrial stoves in Hefei City. There exists plenty of gypsum in atmospheric particulates, which account for the fact that SO 2 pollution is relatively severe in Hefei area.

Abstract:Based on X-ray diffraction and scanning electron microscopic analyses of Quaternary clayey soil from Kunming basin area, the authors have extensively studied the combination, mineralogy and micro-textures of the clay minerals, and discussed the relationship between the clay minerals and the land subsidence under the overdraft of the groundwater which may alter the combination, micro-textures and physicochemical conditions of the clay minerals. The results show that, under the same condition, the content, mineral combination and micro-textures of the clay minerals play most important roles in leading to land subsidence.

Abstract:In this paper, the significance of studying minerals in coals is expounded, the components and characteristics of such major minerals in coals as clay mineral, carbonate, quartz and sulfide are described, and the relationship between minerals and archaic sedimentary environment is also discussed. In addition, the new advances made both at home and abroad in mineral research of coals are recounted, and the present mineral researches on coal are summed up.

Abstract:This paper has dealt with TiO 2/minerals compound photocatalysis material carried by natural zeolites and bentonite, and studied their degradation and discoloration characteristics to organic dyes RB under color illumination. The experiment has proved that samples not calcined have better photocatalysis capacity than those disposed at high temperature. The decoloration ratio of RB solution with TiO 2/zeolites is 100 percent and that with bentonite is 94 percent. Both XRD and TG-DTA analytical results show that anatase can be formed directly at the surface of minerals and combined solidly with the minerals, accompanied by the adjustment of mineral structures.

Abstract:Mineral fertilizers were prepared by the cation exchange method. The adsorption isotherms of Zn2 -adsorbing montmorillonite and vermiculite assume double "S" shape, while the adsorption isotherms of Zn2 - adsorbing zeolite are of "Langmuir" form. The adsorption capacity gradation of three Zn2 -adsorbing minerals is montmorillonite > vermiculite > zeolite. The result of potted plant shows that the biomass of the second batch of corn applied with zinc fertilizer is better than CK (without application of zinc fertilizer). In the first batch, the biomass of vermiculite-Zn is the best, whereas in the second batch, the biomass of montmorillonite-Zn is the best. XRD, IR, DTA and TG were also used to analyze the crystal structure of minerals and mineral zinc fertilizers. The results reveal that vermiculite-Zn can be used as quick-acting zinc fertilizer, while montmorillonite-Zn can be used as long-acting slowly-released zinc fertilizer.

Abstract:Organobentonite was synthesized by placing cetyltrimethylammonium bromide (CTMAB) surfactants into montmorillonite layer in bentonite. The factors affecting the capacity of organobentonite for adsorbing such organic contaminants as phenol, aniline, benzene, toluene and xylene from refuse percolate were investigated, and the laws governing the adsorption of organic contaminants are summarized. It is shown that the key factor affecting the adsorption of organic contaminants by organobentonite is the amount of the modification reagent. When the amount of modification reagent is identical, the ability of organobentonite with Na is obviously better than that of 6% directly-modified organobentonite, and the influence of organobentonite prepared by heat treatment on adsorbing organic contaminants is different from that prepared by acid treatment. The organobentonite can be used to build liner of landfill.

Abstract:Heavy metal pollution produced by human activities has now become a very serious environmental problem. In this paper, the authors briefly describe the origin and seriousness of heavy metal pollution in our environment and summarize the modes of occurrence of heavy metals in soil, water and sediments. The layer silicates and clay minerals are emphatically discussed for the purpose of preventing and controlling heavy metal pollutants, and the mechanism, possibility and current application of their functions against heavy metal pollution are also dealt with. In addition, the authors present here a new idea that layer silicates and their weathered products can serve as a carrier of harmful heavy metal elements in environmental protection.

Abstract:This paper deals with the removing of pyritic sulfur from coal by means of biotechnology, which includes bioleaching and microbial retreat and floatation. The coal samples used , whose total sulfur was 2.30%, were taken from the Third Hongyang Mine in Shenyang. Through the process of bioleaching which lasted for 20 days, the total sulfur was reduced to 1.2% and the removing rate of sulfur was 47.83%. The suspension of thiobacillus ferrooxidans (T.f for short) can affect the desulphurizing results notably in the process of microbial retreat and floatation. Under the reasonable condition, the removing rate of sulfur can be increased by 10% or so in the period of microbial pretreatment which lasted for only 3 to 10 minutes.

Abstract:A three-component mineral material consisting of mica, clay and carbonate was used to make a composite characterized by heat insulation, insulation, anti-static pressure. Its chemical composition, mineral phase, electric property, mechanical property and temperature in use were analysed. The ordinary procedure has been established for composing the mica composite and the thin board. The test under high temperature and medium pressure shows that the mica composite has good properties of heat insulation, insulation, and anti-static pressure. It can replace the asbestos board in the process of firing the man-made diamond products.

Abstract:One of the most important properties of tourmaline is its electric property. Tourmalines have spontaneous and permanent poles, which form electrostatic fields around tourmaline particles with c axial planes as two poles. The effect of the electrostatic field of tourmaline can be expressed as follows: under the action of the electrostatic field, water molecules are electrolyzed and hence produce active molecules H3O and OH-, in which the former attract impurities or dirts to tourmaline surface, thus purifying the water, whereas the latter combine with water molecules to form negative ions, hence improving living conditions of the mankind; charged particles are attracted by electric fields so that charged particulates in air are attracted to tourmaline and the air is purified. Tourmaline has high mechanical and chemical stability: compared with other minerals with absorption capacities such as zeolite and montmorillonite, tourmaline shows high repeated availability without saturation limit, so its application to the environmental protection field has brilliant prospect.

Abstract:XRD and IR analyses show that the main phase of Xiangtan manganese ore from Hunan Province which contains manganese oxides is monoclinic cryptomelane. The accurate crystal_chemical formulae of natural samples 1#and 2#are (K0.51Na0.13Ca0.027)(Al0.168Fe0.091Zn0.046P0.043Ni0.027Ti0.021Mg0.016) Mn2+0.162Mn4+7.452 O16and (K0.57Na0.034Ca0.018)0.622(Mn7.695Ti0.022Cu0.02Ni0.02Zn0.006Al0.003)7.766, respectively, which are calculated by the combination of the magnetic system and electron microprobe analyses. This cryptomelane belongs to nano grade particles because the diameter of its crystal particles is between 30nm to 110nm as shown by Atomic Force Microscope (AFM). The parameters of crystal cell area0=0.9803 nm,b0=0.2849 nm,c0=0.9665 nm,β=91.2°, which are given by the correction of the Reitveld Powder Diffraction Profile Fitting Technique.There are two kinds of tunnels in the crystal structure, and K+ions are located in the larger tunnels constructed by [MnO6] octahedrons. Generally, the crystal_chemical characteristics of natural cryptomelane possess five favorable environmental properties, i.e., surface adsorption, redox, ion exchange, tunnel and nano particle effect.

Abstract:The study on intercalation or adsorption of some organic compounds in kaolinite or its surfaces and its stability is made in this paper. The organic compounds include dimethyl sulphoxide, acrylamide and silane coupling agents. The c-axis spacing in kaolinite expands to a large value of 1.1454 nm as a result of intercalation of polar compound into kaolinite. Acrylamide can be intercalated into kaolinite by virtue of dimethyl sulphoxide and is stable in kaolinite after being heated. Adsorption of silane coupling agents onto kaolinite surfaces is also stable and results in the formation of organic kaolinite.

Abstract:In this paper, the current researches on the application of modified bentonite to such aspects of environmental protection as environmental remediation, environmental purity and environmental substitute function are summarized. The prospect of applying modified bentonite to environmental protection is also presented.

Abstract:The Cu-vermiculite, with 5.5% copper (equal to 80% CEC of vermiculite) and excellent antibacterial performance, was obtained by ion exchange method based on its specialty in cation exchange. On the basis of XRD, TEM and EDS analyses combined with calculation of crystalline parameters and crystal formula, the structure character of Cu-vermiculite was investigated. The similar atom radii and electrovalences of Cu2 and Mg2 suggest that the XRD character of Cu-vermiculite are close to that of standard Mg-vermiculite. A part of Cu2 occupied the interlayer cation sites in the form of hydrate in vermiculite, whereas others turned into octahedral coordinate positions to replace Mg2 . The values of a0 and b0 of the Cu-vermiculite crystal cell had no obvious change compared with that of vermiculite micropowder, but the c0 value slightly decreased, which is desirable for the stabilization of the Cu2 in Cu-vermiculite.

Abstract:At present, the exploratory development of green building goods with high content of fly ash is an important research topic in which fly ash is used comprehensively. High content of fly ash means that the quantity of blended fly ash is not lower than 50 percent of the weight of bricks. The technique of solidifying fly ash invented by us will make the quantity of fly ash amount to 85 percent of the weight of bricks whose compressive strength exceeds 10 Mpa. In this paper, the factors affecting frost resistance and compressive strength of the fly ash brick are discussed. The technique is a new means, which utilizes fly ash effectively and exhibits notable economic, social and environmental results.

Abstract:Attapulgite deposits are rare and valuable in the world. Large iodic attapulgite deposits with total reserves of 2 500 million tons were found in central and western Gansu Province. High iodine exists in attapulgite ores. There is about 0.0418% iodine in western attapulgite ore and 0.0425% in central ore, which are almost the same as the iodine content of niter in Chile. Total reserves of iodine are up to 117,000 tons, with water_soluble iodine higher than 80%. The output of eggs is obviously raised by using iodic attapulgite as chicken feed additives and the iodine content of eggs can reach 22~57 mg/kg.

Abstract:Carbon materials can be used to purify air, water with oil and impurity. After heat-treatment, there are large quantity of vacancy and pore in expanded graphite. The density of this kind of graphite is very low. It can be used to absorb oil in water. The absorbing capacity is larger than that of the active carbon. On the other hands, this graphite can act as the carrier of microorganism that can eat some impurity. With the intercalation of metal in graphite, the property of anti-bacterium can be increased in graphite. With lots of holes, carbon materials can be used as absorbent for waste gas.

Abstract:The preparation method and properties of water glass-acetic ether, plant tannin extract macromolecule chemical sand fixation slurry and pillared montmorillonite as well as aluminum-deficient zeolite are described in this paper. The pillared montmorillonite, aluminum-deficient zeolite, SAP, and radical elements were mixed together in a definite proportion and mode to prepare"complex water-rich nutrition package", which possesses the function of preserving water, fertifizer and soil moisture. Experiments have proved that nutrition package can let the seedling safely pass through a period of trimester survivorship in sandy soil under the conditions of remarkable differences in day and night temperature, no water, no fertilizer and no safeguard of vegetation. The paper puts forward a new idea on desert control on the basis of characteristics of two kinds of sand fixation slurry materials and functions of nutrition package. Chemical sand fixation slurry material is used to fix up quicksand in a relatively large area and create a relatively stable environment for tree growth. Then nutrition package is used for single tree growth when numerous plants form great forest straps and woodlands. In this way, underground preservation of water, surface sand fixation and forest growths can form a three-dimensional comprehensive capacity for desert control.

Abstract:Studies show that some special chemical and physical properties of environmental mineral materials can play an important role in reducing SO2 and removing dust during the combustion of low rank coal. One of the most important aims of this paper is to study the mineralogical characteristics of vermiculite from vermiculite mill gangue and apply this mineral to the desulphurization and dust clearing additives during coal combustion. The authors studied the desulphurization stimulative capacities of vemiculite at different high temperatures. In this new kind of desulphurization additives, CaCO3 is the main desulphurization composition, bentonite serves as adhesive, and vermiculite plays the inflation role. The new additive has high desulphurization ratio ranging from 71% to 97%. The desulphurization product-cinder-was investigated and studied by XRD, optic microscope, polariscope microscope, glistening microscope and SEM-EDX. The main compositions are SiO2, CaSO4, glass and oxides, which mainly contain iron. The content and shape of CaSO4 are determined by coal types, combustion temperature, desulphurization additives content and types, etc. Desulphurization mechanisms of new additive made mainly of vermiculite are as follows: inflating of vermiculite at high temperature makes the inside of briquette looser, and more O2 gas can permeate the outer part of briquette and enter the interior; high concentration of O2 play an important role in forming CaSO4 and restraining the decomposing of CaSO4.

Abstract:The present conditions, charateristics, development trend, and main ways as well as measures for resource recovery of industrial solid waste in Guizhou are analysed in this paper.

Abstract:Through experiments, the content proportion for producing gypsum tailings wall materials and the optimum amount of CaO composite additives were determined in this paper. Using X-Ray Diffractometer(XRD)and Scanning Electron Microscope(SEM), the authors studied the sorts and structures of hydration products and tested their mechanical performance.

Abstract:The sorption percentages of organic contaminants from refuse percolate by Na-, Ca 2 -, Al3- and Cr3 -saturated montmorillonite and their influencing factors are studied in this paper. The results show that the sorption capacities of montmorillonite saturated by trivalent cation for phenol and COD are relatively high, and increase in order of Na-, Ca2 -, Al3 - and Cr3 -montmorillonite. Higher pH values are favorable. Under the experimental conditions, the sorption percentages of phenol and COD by Cr3 -montmorillonite are up to 67.5% and 60.3%, respectively. The sorption capacities of the several kinds of montmorillonite for dimethylbenzene are low. Different adsorption effects of different montmorillonite can be attributed to H-bonding mechanism.

Abstract:The mechanism and prevention of eutrophication and algal bloom have been briefly introduced. The critical happen condition for algal bloom has been discussed. Based on the antibacterial technology, the possibilities of controlling algal bloom by adjusting the metal content especially antibacterial metal content in the water has been disscussed.

Abstract:A kind of complexes material composed from several minerals was completed, which can be used for decreasing concentration of fluoride in potable water from 25 mg/L to 0.1 mg/L and increasing Sr concentration to mineralized ground water level, and other component index coming up to the National Standard for drinking water. It is a new type of environment materials with characteristics of long life, low price of manufacture and easy operation.

Abstract:By imitating subsurface surroundings, lab-scale artificial rapid infiltration systems were used to treat bath wastewater in a period of five months. The effects of artificial soil, thickness of sands, loading rate and concentration of influent upon removal effect were studied, and the results provide foundations for designing artificial soil infiltration system to treat bath wastewater.

Abstract:Organic wastewater engenders serious pollution to environment. This paper deals with the experimentation of the wastewater disposal by using pillar-layered rectorite materials. With the application of rectorite material,the removing ratio of COD in wastewater attains 70% under the condition of rectorite material dosage of 15 kg/t and reductant FE dosage of 5 kg/t. If rectorite is applied for the second time to the adsorption,the removing ratio of COD in wastewater can be as high as 92%. The value of COD in treated water is diminished to 96 mg/L and accords with the first level criterion of draining in terms of GB8978-1996. Furthermore, the experiments of the effect of regenerated rectorite material are tried.

Abstract:The main influencing factors and isotherm adsorption in the treatment of Hg(Ⅱ)-bearing wastewater by using natural magnetite were studied on the basis of the theory of adsorbing heavy metal ions on the surface of water-metal oxides and hydroxides. The results show that the disposal can attain 98% when temperature is 25℃, time is 60min, quantity is 20 g/L, pH is 6.40, grain size is smaller than 200 mesh, ionic strength is zero and Hg(Ⅱ) concentration is 1.12 mg/L and that such factors as pH, ionic strength, quantity, Hg(Ⅱ) concentration, grain size, temperature and time exert different degrees of influence on the disposal, of which the influence of pH is the strongest. The research indicates for the first time that the adsorption isotherm of Hg(Ⅱ) on natural magnetite does not show Langmuir and Freundlich isotherm, but assumes plateau isotherm, which is consistent with the isotherm stepwise ion/coordination particle exchange.

Abstract:In this paper, the Chromium_containing wastewater treatment with rectorites as adsorption reagent and with FO2 as redacting reagent has been studied. The sorption behavior of rectorites for chromium (Ⅵ) also were investigated. The result of the experiment shows that under the condition without changing its pH, the amount of the rectorites in 2.5g/L, FO2 0.5 g/L, it can make the wastewater reach the standard and drain off. It 's more economical. The sorption behavior of rectories for chromium (Ⅵ) obeys the Freundlich, lgQ=-1.9102 + 0.3545 lgC.

Abstract:The sorption of Hg2+from aqueous solution was studied under variant conditions. Factors considered included diameters, pH values and different electrolytes .The final equilibrium was attained within 1~2 days.The investigation indicates that the gross adsorption quantity varies mainly with the pH values. In the solution that does not have other electrolytes or contains NaNO3or K2SO4, the gross adsorption quantity reaches the peak in neutral condition. As for the chlorates, the peak appears in the weakly alkaline condition. Comparing the effects of the ions, the authors conclude that the presence of Cl-decreases the gross quantity of the adsorption conspicuously, and the high value metal cations decrease the gross more effectively than the low value cations. The regression equation indicates that the adsorption of Hg2+between the concentration of 5 and 350 mg/L fits the single site langmuir sorption. The maximum adsorption quantity is 27.6 mg/g.

Abstract:This paper states montmorillonite with high holes and heavy adsorption capability, and the research work changes the nature of this mineral. The montmorillonite treated has better thermal stability and adsorption efficiency. This indicates that the montmorillonite treated can serve as an excellent mineral for treating harmful metal ions in wastewater.

Abstract:Apatite (AP) was prepared by solid-phase reaction and sol-gel process. TEM, XRD, IR and BET measurements as well as static-dynamic absorption tests were applied to analyze the influences of specific surface area, crystallinity, lattice defect, crystal lattice parameters, crystalline size, Ca to P molar ratio (R) and calcination temperature (Tc) on the adsorption of F- ions. According to the data obtained, the AP with relatively high crystallinity and large crystalline size has poor adsorption capacity for F- ions and assumes a single molecule layer chemical complexing adsorption mechanism; the acidified AP has good adsorption capacity and responds to a compound mechanism of dissolving-precipitating and nanosurface adsorption; the nanoscale HAP, under the operating conditions of no acidification, room temperature and pressure, non-secondary pollution and comparatively low concentration of F- ions, has excellent adsorption capacity and shows a nanoadsorption mechanism.

Abstract:The experimental study on the adsorption capacity of montmorillonite, kaolinite and illite for Cu2+,Pb2+, Zn2+, Cd2+and Cr3+was conducted under the conditions of pH=4,t=23℃and very low concentrations of heavy metals. In this study, some means were used for the purpose of keeping the original concentrations of heavy metals unchanged and increasing the amount of heavy metals by adding heavy metals_bearing solution into the reaction systems. The adsorption capacities of the three clay minerals for the five heavy metals are found to be in order of montmorillonite > illite > kaolinite. Their adsorption capacities are mainly controlled by their CEC. XRD results of Cu_montmorillonite and Cr-montmorillonite show that Cu2+and Cr3+have entered the interlayer of montmorillonite by cation exchange with Ca2+. Also, adsorption capacities of each mineral are different for different heavy metals: the adsorption capacities of montmorillonite, kaolinite and illite for different heavy metals are in order of Cr3+>Cu2+>Zn2+>Cd2+>Pb2+, Cr3+>Pb2+>Zn2+>Cu2+>Cd2+and Cr3+>Zn2+>Cd2+>Cu2+>Pb2+respectively.

Abstract:In this paper, a preliminary study is carried out on factors affecting the adsorption of heavy metals (Zn2+) by bentonite. It has been found that the quantity of adsorption increases with the increase of adsorption temperature, initial concentration of heavy metal cations, pH value of solution, time of adsorption and speed of stirring, and the decrease of bentonite particulate size. The mechanism of adsorption affected by various factors is also discussed.

Abstract:In this paper, the factors affecting the adsorption of aqueous cadmium on Hap are investigated. Laboratory experiments show that the cadmium removal efficiencies decrease with the decrease of initial concentration of the solution, and increase with the increasing pH, reaction time (t) and Hap concentration (ρ). Orthogonal experiments indicate that the optimum conditions for the adsorption areρ=5 g/L, pH=6 andt=5 min, respectively. The experimental results demonstrate that synthetic hydroxyapatite could be used as an adsorbent for cadmium removal.

Abstract:The removal of Pb2+from chrome yellow wastewater by hydroxylapatite adsorbent has been investigated with the batch method. The experimental result shows that, when 200~400 g/t hydroxylapatite adsorbent is used and the stirring time is longer than 60 minutes at normal temperature, the mass density of Pb2+in chrome yellow wastewater is reduced to lower than 0.5 mg/L, which comes up to the standard of industrial drain water(1.0 mg/L).