Preparing New Ceramic Membranes from Syrian Zeolite Coated with Silver Nanoparticles to Treatment Wells Water

: As a result of the exacerbation of the problem of water pollution, research was directed towards studying the treatment using ceramic membranes, which proved to be highly effective in treating all water sources. The research aims to study the possibility of preparing a new type of ceramic membranes from Syrian zeolite that was not previously used in this field. In this research, ceramic membranes were prepared from Syrian raw zeolite in several stages. Zeolite sample was characterized, grinded, mixed with boric acid, pressed to form desks, treated thermally according to experiment program, finally coated with silver nanoparticles . Specifications of prepared membranes were determined according to reference methods, effectiveness of prepared membranes were tested in well water handling, that water sample was filtrated through prepared membranes, and then it type MAC, so removal degree was 100%, While removal degree was 97% for bacterial strains on Agar with type PCA, 93% on Agar with type PDA which were conformed to Syrian standard /45 /2007.


Introduction:
Ceramic membranes refer to the prepared membranes from porous ceramics as aluminum oxide, silicon dioxide, clay or substrates like titanium dioxide and zirconium dioxide. Ceramic membranes have wide applications mostly in separation techniques as solid-liquid and solid-gas. Ceramic membranes with the largest pore size have been prepared at bottom as support, and pore size decreases slowly towards the surface where the real separation occurs, these structures are amenable to modifications depending upon the selection of preparation methods: from inner structures to top surface of membranes. Ceramic membranes have several shapes: tubular, multi-channel monolith membrane etc [1][2][3][4][5][6][7] .
Ceramic membranes can be prepared by several methods including slip casting, tape casting, extrusion and, powder pressing which change the particle suspension to a membrane forerunner to form symmetric and composite ceramic membranes [8][9][10][11] Many researches have established the effectiveness of these membranes in water treatment, as they are characterized by excessive chemical stability and mechanical stability and can resist different temperatures, but their preparation needs excessive attention and effort [12][13][14][15][16] .
Because water pollution is prevalent in all places, research is directed towards natural raw materials as raw materials for producing this type of membranes such as raw zeolite, which has great chemical effectiveness and ion exchange and adsorption makes it usable in purifying drinking water, in organic chemical industries, and in increasing the effectiveness of agricultural fertilizers. It can also be used to conserve soil moisture, and to make fodder. Zeolitic metals distinct in their crystalline structure (Fig. 1), where the tetrahedrons that make up them are aligned and interconnected in a certain way to form tetrahedral star rings, which interconnect to form structures contain relatively large voids that connect with each other to form tubes and channels give characteristic porous structure 17,18 . The aim of this research is to prepare ceramic membranes from Syrian zeolite coated with silver nanoparticles to treat wells water, because there is no previous study that prepares ceramic membranes from Syrian zeolite, and a new method was employed by grafting with nano silver for these membranes.

Materials and Methods: Raw Zeolite
Raw zeolite was brought from Mekhelatsouth of Syria, the samples were grinded to 63-100 µm grain size by laboratory mill. Zeolite properties was determined as: -Chemical Composition by X-ray (X-ray fluorescence XRF) An amount of 10 g of grinned zeolite was mixed with 3g of H3BO3 and pressed in a metal mold almost 150 KN to form a disc with 30 mm diameter and 5 mm thickness.

-Differential Thermal Analysis of Zeolite
The sample was heated gradually by 10°C/min, to temperature 1400°C.

Preparation of Membranes
Membranes were prepared by powder press technique Fig. 2. Zeolite was mixed with boric acid as a binder by 5% w/w, in the next stage, the mixture was pressed into a tubular meal to obtain desks with 5 cm diameter and 2-2.5 mm thickness formation press was 100 kg/cm 2 . Then treated thermally according to experiment program after several tests by noting several points: the appearance of cracks, the collapse of the sample, the stability of the weight Specifications of prepared membranes were determined according to reference methods: apparent porosity, apparent specific gravity, water absorption, and bulk density were measured by (ASTM C20-00), to determine permeability Darcy's law method (k=Q.µ.∆L/A.∆p) where Q: volumetric flow rate, k: membrane permeability, A: membrane surface area, ∆p: pressure difference between the two membrane surfaces, μ: dynamic viscosity of the fluid and ∆L: thickness of membrane. Chemical stability of the prepared zeolite membranes were measured by immersing zeolite membranes in a NaOH (pH=13.5) and HCl (pH=1.0) separately for 48 hours, then measured the change of weight 19,20 .

Coating of Membranes with Nanosilver Particles
To enhance antibacterial properties, prepared membranes were immersed in 100ml of 0.01M silver nitrate solution for 15 minutes, then 5ml of 5% sodium citrate solution (a reducing agent for silver ions) was added to it, after 15 minutes, membranes were treated with UV for 03 minutes, where the color changed to silver as a result of the conversion of silver ions to silver nano particles. Membranes were washed with 3% sodium chloride solution to remove silver ions, then washed with distilled water then dried at 105°C Fig. 4.
With nano silver Without nano silver

Treating of Well Water
Well water sample was collected from north Aleppo. Chemical and microbiological analysis was performed to measure its content of different impurities as maintained by reference methods as: Chemical Analysis COD: by photometric method, sample was digested by K2Cr2O7 and H2SO4, color strength was compared with a standard sample. BOD: BOD5 was measured by pressure feeler technique. TDS: conductivity/TDS device was used. Turbidity: by measuring the intensity of light scattered in certain settings.

Metals: atomic absorption technique was used Microbiological Examination
Culture media were prepared in purified water, treated in an autoclave at temperature of 121°C for 15 minutes, then poured into sterile 9 cm petri dishes, then incubated in incubators. Full of bacteria, faecal coliforms, Escherichia coli, salmonella and fungi, incubating at temperature 25 °C for 4 days then was applied on fungi plates to give the final effect (colony/100 ml). Culturing was performed on Agar with type PCA. Existence of faecal enteric bacteria was revealed by the colonies growing on Agar with type MC. Escherichia coli appeared green with metallic luster colonies on Agar with type EMB, salmonella was appeared as black colonies on Agar with type SS. Fungi were noticed by growing on agar with type SDA. Sample of water was filtrated with zeolite membranes. Lastly sample was filtered by zeolite membrane which was coated with silver nanoparticles. Chemical and microbiological specifications of the water sample were measured after the processing to prof the efficacy of the processing.

Chemical Composition
Chemical analysis XRF for studied zeolite is shown in Table 1, it is noted that zeolite sample contained a high percent of silicon dioxide SiO2, which corresponds to the siliceous structure of zeolite, aluminum oxide Al2O3 which forms with silicon dioxide SiO2 the steric structure of various zeolitic metals, sample also was contained iron oxide Fe2O3, which can exist unbound (free), and presence of sodium oxides Na2O and potassium K2O was noted, which has a special importance in ion exchange.

Mineral Phase
Spectrum of XRD showed that studied zeolite mostly contains Analcime, Phillipsite, Chabazite. another peaks produced by presence other secondary metal phases like hematite and calcite Fig. 4, Table 2   Deferential Thermal Analysis DTA Differential thermal curve of raw zeolite showed the presence of several peaks: 1. Endothermic reaction at 90-100 o C refers to evaporation of moisture water accompanying the zeolite sample. 2. Endothermic reaction at 300-400 o C which indicates loss of bound water in the form of hydroxyl groups. 3. Endothermic reaction at 650-750 o C refers to decomposition of carbonates associated with raw zeolite. 4. Exothermic reaction at 800-850 o C refers to due to recrystallization after the destruction of the zeolite structure Fig. 5.

Characteristics of Prepared Membranes
Spectrum of XRD showed that zeolite membranes mostly contain Diopside, Augite, Anorthite, Pyroxene . In addition, some peaks were produced by the presence other secondary materials Fig. 6, Table 3.
Properties of the prepared membranes were: water absorption 16.05%, apparent porosity 26.68%, bulk density 1.74 g/cm 3 , volumetric flow 1.48 x10 -6 m3/sec, permeability 0.0032 darcy (permeability unit). Zeolite membranes were more stable in acid than in base medium, loss in weight after base processing was 0.015%, while after acid processing was 0.049%.

Filtration of Well Water
Water before processing contained different of pollutions (chemical and biological); COD decrease to 96.9%, BOD to 95.45%, turbidity to 90%, TDS to 59.66%, the sample was almost free of heavy metals by atomic absorption analysis There was important decrease in total bacterial of the handled sample almost 0% on Agar with type MAC, so removal degree was 100%. While removal degree was 97% for bacterial strains on Agar with type PCA, 93% on Agar with type PDA, as shown in Table 4, Fig. 7. Table 4. Specification of well water before and after treatment.

Conclusion:
Ceramic membrane can be prepared from Syrian raw zeolite by powder press method. Prepared zeolite membranes had high effectiveness in the treatment of wells water. Results showed that prepared zeolite membranes had high effectiveness through decreasing chemical and microbial pollutants, COD decreased to 96.9%, BOD to 95.45%, Turbidity to 90%, TDS to 59.66%. There was an important decrease in total bacterial of the handled sample almost 0% on Agar with type MAC, so removal degree was 100%, While removal degree was 97% for bacterial strains on Agar with type PCA, 93% on Agar with type PDA which were conformed to Syrian standard /45 /2007