Composite membranes with cellulose acetate surface layer for water treatment

2021 ◽  
Vol 2 ◽  
pp. 32-40
Author(s):  
D. D. Fazullin ◽  
◽  
L. I. Fazullina ◽  
G. V. Mavrin ◽  
I. G. Shaikhiev ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Cellulose Acetate ◽  
Heavy Metal Ions ◽  
Tap Water ◽  
Substrate Surface ◽  
Composite Membranes ◽  
Specific Productivity ◽  
Absorption Bands ◽  
Ultrathin Layers

Microporous composite membranes containing from one to three ultrathin layers were obtained by multistage immersion of a paper base in a solution of cellulose acetate in acetone. The physicochemical properties of membranes have been studied and the parameters of membrane separation of heavy metal ions from tap water have been determined. An increase in the particle size and a decrease in the absolute value of the ζ-potential with an increase in the concentration of cellulose acetate in acetone were revealed. It was found that the porosity of the membranes increased from 47 % to 51 % depending on the number of ultrathin cellulose acetate layers on the substrate surface. A decrease in the moisture absorption of composite membranes and an increase in the contact angle of wetting with distilled water from 30.0° to 68.8°, depending on the number of ultrathin layers, were noted. Microscopic examination of the membrane surface showed that the ultrathin layer consists of many pores with sizes less than 1 micron. The absorption bands in the IR spectra of cellulose acetate and the surface of the composite microporous cellulose acetate (MAC) membrane are identical. The retention capacity of MAC composite membranes, determined by iron ions from an iron (III) chloride solution, ranged from 47.5 to 97.4 % depending on the number of cellulose acetate layers on the substrate surface with a specific productivity of 27.9 to 7399 dm3/(m2·h) and a pressure of 0.35 MPa. A high selectivity of a microporous membrane of three layers of cellulose acetate (MAC3) with respect to heavy metal ions contained in tap water was established: Cr3+ (96 %) > Cu2+ (92 %) > Fe3+ (90 %) > Mn2+ (45 %).

Metal in situ surface functionalization of polymer-grafted-carbon nanotube composite membranes for fast efficient nanofiltration

2017 ◽  
Vol 5 (2) ◽  
pp. 583-592 ◽  
Author(s):  
Faizal Soyekwo ◽  
Qiugen Zhang ◽  
Runsheng Gao ◽  
Yan Qu ◽  
Ruixue Lv ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Carbon Nanotube ◽  
Metal Ions ◽  
Surface Functionalization ◽  
Heavy Metal Ions ◽  
Composite Membranes ◽  
Carbon Nanotube Composite

Metal in situ surface functionalized PEI-g-MWCNT membranes are facilely prepared for nanofiltration of heavy metal ions in solution with high fluxes.

Removing heavy metals from effluents with natural and modified clay-containing sorbents

2021 ◽  
pp. 30-37
Author(s):  
А.К. Стрелков ◽  
С.В. Степанов ◽  
О.Н. Панфилова ◽  
А.В. Арбузов
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Specific Productivity ◽  
Natural Material ◽  
Main Process ◽  
Tertiary Treatment ◽  
Modified Clay ◽  
Cartridge Filter

Представлены результаты исследований сорбции ионов тяжелых металлов глиносодержащими сорбентами из сточных вод гальванического производства. Цель испытаний, проведенных на пилотной установке, – разработка технологической схемы для доочистки сточных вод от ионов тяжелых металлов и извлечения отработанного сорбента с применением намывного патронного фильтра со слоем перлита. В испытаниях использовались: термически модифицированный сорбент на основе природных материалов – модифицированная глина, а также смесевый сорбент, состоящий из монтмориллонита, торфа и доломита в соотношении 5:4:1 без термической обработки. Исследования проводились по восьми ионам тяжелых металлов в диапазоне низких концентраций, характерных для сточных вод, поступающих на доочистку после отстаивания с корректировкой рН. Основные технологические параметры доочистки: pH8; продолжительность контакта сорбента с обрабатываемыми водами 90 мин, доза сорбентов 1–1,6 г/л. Отделение отработанного сорбента от очищенной воды было предусмотрено в две ступени – отстаиванием и фильтрованием на патронном намывном фильтре. Введение коагулянта «Аква-АуратÔ-30» дозой 40 мг/л по Al2O3 позволило снизить концентрацию взвешенных веществ в осветленных сточных водах, подаваемых на намывные фильтры, до 8 мг/л для модифицированной глины и 15 мг/л для смесевого сорбента. Удельная производительность намывного слоя составила 23 м3/(ч×м2), расчетная удельная нагрузка по взвеси на поверхность фильтра составила для модифицированной глины 850 г/м2, для смесевого сорбента – 680 г/м2. Расчетная продолжительность фазы фильтрования намывного слоя при использовании предварительного реагентного отстаивания составила 4,6 и 2 ч для модифицированной глины и смесевого сорбента соответственно. Обеспечена эффективность очистки сточных вод от ионов тяжелых металлов на уровне ПДК для водных объектов рыбохозяйственного значения. The results of studies of the sorption of heavy metal ions by clay-containing sorbents from plating effluents are presented. The purpose of the tests carried out in a pilot plant was developing a process scheme for the removal of heavy metal ions from effluents and extraction of the spent sorbent in a precoat cartridge filter with a layer of perlite. The materials used in the tests were as follows: thermally modified sorbent based on natural material, i. e., modified clay, as well as mixed sorbent consisting of montmorillonite, peat and dolomite in a ratio of 5:4:1 without heat treatment. The studies were carried out on eight ions of heavy metals in the low concentration range typical for the effluent coming for tertiary treatment after sedimentation with pH adjustment. The main process parameters of tertiary treatment were: pH 8; the duration of the sorbent contact with the effluent was 90 min, the dose of sorbents was 1–1.6 g/l. The separation of the spent sorbent from the effluent was executed in two stages – sedimentation and filtration in a precoat cartridge filter. The addition of Aqua-AuratTM-30 coagulant with a dose of 40 mg/l as Al2O3provided for reducing the concentration of suspended solids in the clarified effluent supplied to the precoat filters to 8 mg/l for modified clay and 15 mg/l for the mixed sorbent. The specific productivity of the alluvial layer was 23 m3/(h‧m2), the specific load of the suspension on the filter surface was 850 g/m2for modified clay, and 680 g/m2 for mixed sorbent. The estimated duration of the filtration phase of the alluvial layer while using preliminary chemical sedimentation was 4.6 and 2 h for the modified clay and mixed sorbent, respectively. The efficiency of removing heavy metal ions from effluents was provided at the level of the maximum permissible concentration for fishery water bodies.

scholarly journals Preparation of PVDF/Hyperbranched-Nano-Palygorskite Composite Membrane for Efficient Removal of Heavy Metal Ions

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 156 ◽  
Author(s):  
Xiaoye Zhang ◽  
Yingxi Qin ◽  
Guifang Zhang ◽  
Yiping Zhao ◽  
Chao Lv ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Adsorption Capacity ◽  
Composite Membrane ◽  
Heavy Metal Ions ◽  
Thermo Gravimetric Analysis ◽  
Composite Membranes ◽  
Gravimetric Analysis ◽  
High Adsorption ◽  
High Adsorption Capacity

In this work, three kinds of hyperbranched polyamidoamine-palygorskite (PAMAM-Pal) were designed and synthesized by grafting the first generation polyamidoamine (G1.0 PAMAM), G2.0 PAMAM and G3.0 PAMAM onto Pal surfaces, respectively. Then, these PAMAM-Pals were used as additives to prepare polyvinylidene fluoride (PVDF)/hyperbranched polyamidoamine-palygorskite bicomponent composite membranes. The structures of the composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TEM), X-ray photoelectron spectroscopy (XPS), field-emission scanning electronmicroscopy (SEM), atomic force microscope (AFM) and Thermogravimetric analysis (TGA). The adsorption properties of composite membranes to heavy metal ions was studied, and the results found that the maximum adsorption capacities for Cu(II), Ni(II) and Cd(II) could reach 155.19 mg/g, 124.28 mg/g and 125.55 mg/g, respectively, for the PVDF/G3.0 PAMAM-Pal membrane, while only 23.70 mg/g, 17.74 mg/g and 14.87 mg/g could be obtained for unmodified membranes in the same conditions. The high adsorption capacity can be ascribed to the large number of amine-terminated groups, amide groups and carbonyl groups of the composite membrane. The above results indicated that the prepared composite membrane has a high adsorption capacity for heavy metal ions removal in water treatment.

scholarly journals Cellulose acetate-Sn(IV) molybdophosphate: A biopolymer supported composite Exchanger for the removal of selected heavy metal ions

2020 ◽  
Vol 34 (2) ◽  
pp. 259-276
Author(s):  
A. M. Taddesse ◽  
T. T. Ketema ◽  
E. Teju
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Cellulose Acetate ◽  
Heavy Metal Ions ◽  
Sol Gel ◽  
Basic Medium ◽  
Separation Potential ◽  
Toxic Heavy Metal ◽  
Gel Method ◽  
Sol Gel Method

Cellulose acetate-tin(IV) molybdophosphate (CATMP) composite exchanger was prepared by mixing biopolymer celluloseacetate with its inorganic counterpart tin(IV) molybdophosphate (TMP) using sol‑gel method. The physical characterization of the as synthesized exchanger was carried out by FTIR, XRD, BET, TGA-DTG and SEM-EDX techniques. Chemical properties such as ion exchange capacity, chemical stability, pH and distribution behavior were carried out. The average IEC of the composite material, as determined by batch equilibrium, was found to be 2.43 meq/g for Na+ ion; higher than its inorganic counterpart, i.e. 1.41 meq/g. This exchanger was also found to be stable in water, acids and organic solvents, but unstable in basic medium. The distribution study (Kd) of the exchanger in different solvent systems showed promising separation potential of the exchanger towards metal ions of analytical interest from a given mixture of toxic heavy metal ions. The sorption studies revealed that the material was selective for Cr(III) and Cd(II) ions and moderately selective for Co(II) ion in solvents employed in this work. Its selectivity was examined by achieving some important binary separations of metal cations on its column indicating its promising application in environmental pollution abatement.                     KEY WORDS: Cation exchanger, Biopolymer, Organic-inorganic hybrid, Sol–gel method, Binary distribution   Bull. Chem. Soc. Ethiop. 2020, 34(2), 259-276 DOI: https://dx.doi.org/10.4314/bcse.v34i2.5

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