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1

Environment Friendly Approach to Simultaneously Remove Unfixed Dyes from Textile Fabric and Wash-off Liquor

100%

Shaikh I. A. , Muqddas A. , Jamil N. , Qadir A.

Fibres & Textiles in Eastern Europe

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2016

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tom Vol. 24, no. 3 (117)

124--129

EN

A new idea was investigated in this study wherein the use of coagulants was assessed in the wash-off process to simultaneously remove unfixed reactive dyes from fabrics and wash off liquor. At the end of dark shade dyeing (5% owf) with C.I. Reactive Yellow 145, C.I. Reactive Red 194, and C.I. Reactive Black 5, fabrics were subjected to both conventional and new wash-off methods, and comparisons were made. The effectiveness of coagulant wash-off was evaluated in terms of the change in shade, wash fastness, rubbing properties, and colour difference values (ΔL*,ΔC*, Δh* & ΔE*). The colour removal efficiency (%) of liquor was considered as indicative of the removal of unfixed dyes from the fabric. Overall results have shown that the use of alum and MgCl2 coagulants during the wash-off process can achieve up to an 87% reduction in the colour of wash-off liquor, without compromising the colour properties of the dyed substrate.

PL

W pracy przedyskutowano nową koncepcję polegającą na zastosowaniu koagulantów w procesie prania z jednoczesnym usunięciem niezwiązanych barwników reaktywnych z tkanin tekstylnych i płynów pralniczych. Oceniano zmiany odcieni zabarwienia przy barwieniu barwnikami C.I. Reactive Yellow 145, C.I. Reactive Red 194 i C.I. Reactive Black 5; dla porównania materiały barwione poddano tradycyjnemu praniu i obróbce według opracowanej metody. Wyniki badań wykazały, że stosowanie koagulantów ałunu i MgCl2 podczas procesu pralniczego prowadzi do 87% redukcji koloru płynu pralniczego bez równoczesnego wpływu na kolor barwionych tkanin.

2

Photocatalytic degradation of synthetic textile effluent by modified Sol-Gel, synthesized mobilized and immobilized TiO2, and Ag-doped TiO2

100%

Akram T. M. , Ahmad N. , Shaikh I. A.

Polish Journal of Environmental Studies

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2016

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tom 25

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nr 4

EN

Advanced oxidation processes (AOPs) have proven to be very effective for treating various hazardous organic pollutants in water. The present study uses a double-walled horizontal glass reactor (DHGR) to investigate heterogeneous UV/TiO2 (titanium dioxide) and UV/Ag-TiO2 (mobilized and immobilized) photocatalytic degradation of synthetic textile effluent (Remazol Red RGB) with UV (400W). The textile effluent was characterized in terms of pH, chemical oxygen demand (COD), and degree of decolorization (at 519 nm) before and after treatment. Optimum degradation results were obtained at pH3. We also found that with different catalysts and catalyst doses, the rate of degradation rises up to a maximum “critical” value. The electron scavenger was Ag-led to a faster degradation of synthetic textile effluent in the photocatalytic system. The photocatalytic degradation proved to be dependent on the effluents’ initial COD, catalyst dose, catalyst form, and pH of the medium. Results reveled that among different forms of catalysts, Ag-TiO2 (Mesh) and TiO2 (0.5 g) showed better COD percentage and ABS percentage removal at pH3 with initial concentrations of synthetic effluent 560mg/l under UV(400W) irradiation.

3

Characterization and optimization of photocatalytic activity of sol gel-synthesized TiO2 and Ag-doped TiO2 through degradation of synthetic textile effluent by UV lamp-assisted experimental setup

100%

Akram T. M. , Ahmad N. , Shaikh I. A.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 4

EN

The textile industry is one of the largest producers of harmful effluent, and this has become a serious threat to the environment when disposed of into water bodies, which may lead to high pollution risk – especially in developing countries. There are several treatment methods ranging from conventional to advanced for treating textile effluent before disposal in the environment. Photocatalytic oxidation (AOPs) is the most sophisticated process among all other advanced oxidation processes. In this study, TiO2 and Ag-doped TiO2 were used for the photcatalytic degradation of synthetic textile effluent. TiO2 and Ag-doped TiO2 catalyst were synthesized through two routes of sol-gel method (M1 and M2 reported in our previous study) for mobilized and immobilized utilization purposes [1], and characterization of the catalysts was carried out through X-ray diffrectrometric analysis. XRD patterns showed that catalysts synthesized by both routs of sol-gel method were initially found in amorphous form as no peak appeared in an X-ray diffractrogram at 0ºC calcination (catalyst without calcinations), whereas with an increase of temperature the amorphous form of catalyst turned into crystalline. Results showed that TiO2 synthesized by the sol-gel route showed anatase phase at 350ºC, and peaks kept growing until 550ºC. Furthermore, at 650-750ºC anatase and rutile co-exist, while in Ag-doped TiO2, anatase appeared at 350-450ºC and at 550ºC anatase phase/silver co-existed, whereas at 650-750ºC anatse-silver-rutile co-existed. An X-ray diffractrogram showed that catalyst synthesized through the 2nd sol-gel route also possessed an amorphous nature at 350ºC and peaks of anatase phase of TiO2 appeared at 450ºC and kept growing sharper as temperature increased from 450-750ºC, whereas anatase peaks detected at 350ºC in Ag-TiO2, and anatase-silver co-existed at 450ºC and 550ºC. Hence, anatase disappearedand only silver metal peaks remained at 650-750°C. Degradation and decolorization results revealed that optimum photocatalytic activity was achieved by catalysts calcinated at 550ºC as 91.96% degradation (COD removal %) with Ag-doped TiO2 immobilized catalyst, and 99.57% decolorization (colour removal percentage) was achieved with Ag-doped TiO2 mobilized catalyst on 60 min treatment of synthetic textile effluent (Remazol red RGB: 10 ppm concentration, pH3). Results showed that Ag-doped TiO2 developed anatase crystalline phase at 550ºC that favored degradation and decolourization. The order of catalyst calcination at 550°C with respect to degradation was found as Ag-TiO2 (immobilized) > Ag-TiO2 (mobilized) > TiO2 (mobilized) > TiO2 (immobilized) and decolourization found as Ag-TiO2 (mobilized) >Ag-TiO2(immobilised)> TiO2 (immobilized) > TiO2 (mobilized).

4

Reuse of textile wastewater after treating with combined process of chemical coagulation and electrocoagulation

63%

Ali A. , Shaikh I. A. , Abit T. , Samina F. , Islam S. , Khalid A. , Firdous N. , Javed M. T.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 4

EN

The basic aim of our research was to reduce water consumption in the dying process in the textile industry. This study evaluated the treatment efficiency of combined process of chemical coagulation and electrocoagulation on the synthetically produced dyes C.I. Reactive Yellow 145 and C.I Reactive Red 194. The wash-off liquor generated during the dyeing process was decolorized by adding a mixture of alum and chitosan, followed by electrocoagulation and reused for the wash-off of dyes. Fabric color was analyzed by wash fastness, rubbing and crocking experiments. The combined treatment process was proven to be very effective in decolorizing both dyes by 99.1% and 96.15%. The color difference values of standard (dyed in fresh water) and batch samples for both dyes were 0.53 and 0.35, which is within the acceptable limit (≤1.0). The wash fastness test indicated a range of 4-5 for both standards and batch samples. In the case of water quality parameters, a decrease in pH values was observed after treatment; however, an increasing trend was seen in cases of COD, TDS and EC. While these parameters do not affect the color of the fabric in dying process, this study concludes that the combined treatment of chemical and electrocoagulation is very efficient for decolorizing dye wastewater. Reuse of treated wash-off wastewater is suitable not only for reducing water consumption but also reducing wastewater generation in the textile industry. Hence this treatment option will improve overall water efficiency of the textile industry.