As textile production flourishes nowadays, the amount of dyed wastewater entering the
water body has also increased. Dyes could have serious negative impacts to the environment
and also the human health, hence, they need to be removed from the water body. In this
study, layered double hydroxide (LDH) of manganese/aluminium (MnAl) was synthesised
to be used as a potential adsorbent to remove methyl orange (MO) dye due to its unique
lamellar structure which provides LDH with high anion adsorption and exchange ability.
MnAl was synthesized by using co-precipitation method and characterized by powder X-ray
diffraction (PXRD), Fourier-Transform Infrared Spectroscopy (FTIR), Inductively coupled
plasma atomic emission spectroscopy (ICP-AES) and Carbon, Hydrogen, Nitrogen, Sulphur
(CHNS) elemental analysers, and Accelerated Surface Area and Porosity Analyzer (ASAP).
Adsorption studies were conducted at different contact times and dosages of MnAl to evaluate
the performance of MnAl in removing MO from water. Kinetic and isotherm models were
tested using pseudo-first order, pseudo-second order, Langmuir isotherm and Freundlich
isotherm. MnAl LDH was found to be perfectly fitted into pseudo-second order and Langmuir
isotherm.
In this article, the utilization of fungi for the degradation of xenobiotic organic compounds (XOCs) from different wastewater and aqueous solutions has been reviewed. The myco-remediation (myco-enzymes, myco-degradation, and myco-sorption) process is widely used to remove XOCs, which are not easily biodegradable. The removal of XOCs from textile wastewaters through chemical and physical processes has been addressed by many researchers. Currently, the application of oxidative enzymes [manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase] and myco-adsorption is becoming more common for the removal of XOCs from wastewater. Although the advanced oxidation process (AOPs) is a preferred technology for removing XOCs, its use is restricted due to its relatively high cost, which led to research studies on non-traditional and low-cost technology. The current review aimed to organize the scattered available information on the potential of myco-remediation for XOC removal. Moreover, the utilization of agricultural wastes as a production substrate for oxidative enzymes has been reported by many authors. Agricultural waste materials are highly inducible for oxidative enzyme production by fungi and are cost-effective in comparison to commercial substances. It is evident from the literature survey of 80 recently published papers that myco-enzymes have demonstrated outstanding XOC removal capabilities. Fungal laccase enzyme is the first step to degrade the lignin and then to get the carbon source form the cellulose by cellulose enzyme.
Polyhydroxyalkanoates (PHAs) has been investigated for more than eighty years. Ever since then, the scientists are kept on synthesizing and developing new polymers and application to suit human interests nowadays. The resourcefulness of PHAs has made them a good candidates for the study of their potential in a variety of areas from biomedical/medical fields to food, packaging, textile and household material. In medical field (specifically in tissue engineering application), producing a biocompatible 3-D scaffold with adaptable physical properties are essential. However, to the best of our knowledge, scaffolds from PHB and PHBV with thickness greater than 1 mm have not been produced yet. In this work, PHB and PHBV porous 3-D scaffolds with an improved thickness greater than 4 mm was fabricated using conventional method of solvent-casting particulate-leaching (SCPL). A preliminary assessment on the improved thickness 3-D scaffolds was carried out to examine its pore interconnectivity by using non-invasive color staining method. The vertical cross sections image of the stained scaffolds was analyzed by image analyzer software. This technique was considered simple, fast and cost effective method prior to the usage of super accurate analytical instruments (micro-computed tomography). The results showed that over 80% of the pores have been interconnected with the adjacent pores. Moreover, there was a good correlation between the predicted pore interconnectivity and porosity. These results indicated how well a simple technique can do by giving an overview of the internal morphology of a porous 3-D structure material.
Disposal of dye wastewater into water streams without treatment endangers human and marine lives. This work focused on the second largest class of textile dyes after azo dyes due to its high resistivity to biodegradation and high toxicity. The photocatalytic degradation of Reactive Blue 4 (RB4), an anthraquinone dye, has been investigated using pure anatase nano titanium (IV) oxide (TiO2). The dye molecules were fully degraded and the addition of hydrogen peroxide (H2O2) enhanced the photodegradation efficiency. It is found that the degradation as the hydroxyl radicals in the bulk solution is sufficient for complete mineralisation. The disappearance of the dye follows pseudo-first-order kinetics. The effect of pH, amount of photocatalyst, UV-light intensity, light source and concentration of hydrogen peroxide was ascertained.
Carboxymethylcellulose (CMC) is a water-soluble polymer, which is widely used in various
fields such as food additives, textiles, pharmaceuticals and cosmetics. In this study, hydrogel
was prepared from CMC by using calcium chloride as a crosslinking agent. Optimization
of the reaction was done through investigation of four different parameters which had
different percentage of CMC (w/v), percentage of calcium chloride (w/v), reaction time and
temperature. The gel content and swelling properties of the CMC hydrogel were studied.
The highest gel content was 85.33% at 7% of CMC (w/v) with 2% of calcium chloride (w/v)
in 24 hours reaction time at room temperature. The gel content increased with the increasing
concentration of CMC and CaCl2. This was due to the higher number of functional groups
of COO- that were available in more concentrated CMC which could crosslink with CaCl2
to give higher gel content. Increasing the percentage of CaCl2 will increase the electrostatic
attraction between anionic charges of polymer chains and multivalent cation (Ca2+) that
leads to increase in ionic crosslinking of CMC. The swelling properties of CMC hydrogel
showed that the optimum degree of swelling was 45.33 (g/g). The swelling capacity of the
hydrogel in water decreased with the increase of the gel content of CMC hydrogel. This
could be due to the increase in the degree of crosslinking of the CMC hydrogel.
The polyvinyl alcohol (PVA) and neem extract were grafted onto coupled oxides (3ZT-CO) via reflux process to stabilize the particles to form 3ZT-CO/PVA and 3ZT-CO/Neem. These were then incorporated into LLDPE by melt blending process to give LLDPE/3ZT-CO/PVA and LLDPE/3ZT-CO/Neem composites. The Neem and PVA stabilized particles showed high zeta potential and dispersed homogeneously in water. The stabilization process altered the shape of the particles due to plane growth along the (002) polar direction. The stabilizers acted as capping agents and initiated the one-dimensional growth. The alkyl chain groups from PVA increased the polarity of the LLDPE/3ZT-CO/PVA and played a dominant role in the water adsorption process to activate the photocatalytic activity. This was further enhanced by the homogeneous distribution of the particles and low degree of crystallinity (20.87%) of the LLDPE composites. LLDPE/3ZT-CO/PVA exhibited the highest photodegradation (93.95%), which was better than the non-stabilized particles. Therefore, the photocatalytic activity of a polymer composite can be enhanced by grafting PVA and neem onto couple oxides. The LLDPE/3ZT-CO/PVA composite was further used to treat textile effluent. The results showed the composite was able to remove dye color by 93.95% and to reduce biochemical oxygen demand (BOD) and chemical oxygen demand (COD) by 99.99%.
Malaysian authorities has planned to minimize and stop when applicable unsanitary dumping of waste as it puts human health and the environment at elevated risk. Cost, energy and revenue are mostly adopted to draw the blueprint of upgrading municipal solid waste management system, while the carbon footprint emissions criterion rarely acts asa crucial factor. This study aims to alert Malaysian stakeholders on the uneven danger of carbon footprint emissions of waste technologies. Hence, three scenarios have been proposed and assessed mainly on the carbon footprint emissions using the 2006 IPCC methodology. The first scenario is waste dumping in sanitary landfills equipped with gas recovery system, while the second scenario includes anaerobic digestion of organics and recycling of recyclable wastes such as plastic, glass and textile wastes. The third scenario is waste incineration. Besides the carbon footprint emissions criterion, other environmental concerns were also examined. The results showed that the second scenario recorded the lowest carbon footprint emissions of 0.251t CO2 eq./t MSW while the third scenario had the highest emissions of 0.646t CO2 eq./t MSW. Additionally, the integration between anaerobic digestion and recycling techniques caused the highest avoided CO2 eq. emissions of 0.74t CO2 eq./t MSW. The net CO2 eq. emissions of the second scenario equaled -0.489t CO2 eq./t MSW due to energy recovery from the biogas and because of recycled plastic, glass and textile wastes that could replace usage of raw material. The outcomes also showed that the first scenario generates huge amount of leachate and hazardous air constituents. The study estimated that a ton of dumped waste inside the landfills generates approximately 0.88m3 of trace risky compounds and 0.188m3 of leachate. As for energy production, the results showed that the third scenario is capable of generating 639kWh/t MSW followed by the second scenario with 387.59kWh/t MSW. The first scenario produced 296.79kWh/t MSW. In conclusion, the outcomes of this study recommend an integrated scenario of anaerobic digestion and recycling techniques to be employed in Malaysia.
Polypyrrole-magnetite dispersive micro-solid-phase extraction method combined with ultraviolet-visible spectrophotometry was developed for the determination of selected cationic dyes in textile wastewater. Polypyrrole-magnetite was used as adsorbent due to its thermal stability, magnetic properties, and ability to adsorb Rhodamine 6G and crystal violet. Dispersive micro-solid-phase extraction parameters were optimized, including sample pH, adsorbent amount, extraction time, and desorption solvent. The optimum polypyrrole-magnetite dispersive micro-solid phase-extraction conditions were sample pH 8, 60 mg polypyrrole-magnetite adsorbent, 5 min of extraction time, and acetonitrile as the desorption solvent. Under the optimized conditions, the polypyrrole-magnetite dispersive micro-solid-phase extraction with ultraviolet-visible method showed good linearity in the range of 0.05-7 mg/L (R2 > 0.9980). The method also showed a good limit of detection for the dyes (0.05 mg/L) and good analyte recoveries (97.4-111.3%) with relative standard deviations
Microplastics have been recognized as emerging pollutants with potential ecotoxicological impact. The contribution of washing machine use to microplastics emission at the household level is still not completely understood. This study aims to characterize microplastic emissions in laundry water from household washing machines from Greater Kuala Lumpur (Malaysia). Microplastics were found between 6.9E-3 and 0.183 g/m3 in laundry water at household level. Microplastic shapes of fiber and fragment consist of polyester, nylon, and acrylic with average length of 2258.59 μm and were also identified in these laundry water samples. Questionnaire survey findings demonstrated fabric properties and washing parameters both likely contribute to microplastic emissions in laundry water and, ultimately, wastewater treatment plant influent. The impact of fabric properties and washing parameter factors on microplastic emission in laundry water at the household level merits further investigation. The findings of this study demonstrated the potential of laundry water as a microplastic source at the household level within a developing country.
Photocatalysis is an ecofriendly technique that emerged as a promising alternative for the degradation of many organic pollutants. The weaknesses of the present photocatalytic system which limit their industrial applications include low-usage of visible light, fast charge recombination, and low migration ability of the photo-generated electrons and holes. Therefore, various elements such as noble metals and transition metals as well as non-metals and metalloids (i.e., graphene, carbon nanotube, and carbon quantum dots) are doped into the photocatalyst as co-catalysts to enhance the photodegradation performance. The incorporation of the co-catalyst which alters the photocatalytic mechanism was discussed in detail. The application of photocatalysts in treating persistent organic pollutants such as pesticide, pharmaceutical compounds, oil and grease and textile in real wastewater was also discussed. Besides, a few photocatalytic reactors in pilot scale had been designed for the effort of commercializing the system. In addition, hybrid photocatalytic system integrating with membrane filtration together with their membrane fabrication methods had also been reviewed. This review outlined various types of heterogeneous photocatalysts, mechanism, synthesis methods of biomass supported photocatalyst, photocatalytic degradation of organic substances in real wastewater, and photocatalytic reactor designs and their operating parameters as well as the latest development of photocatalyst incorporated membrane.
Effluent containing colour/dyes, especially reactive dyes, becomes a great concern of wastewater treatment because it is toxic to human life and aquatic life. In this study, reactive dye of Black B was separated using the supported liquid membrane process. Commercial polypropylene membrane was used as a support of the kerosene-tridodecylamine liquid membrane. Several parameters were tested and the result showed that almost 100% of 70 ppm Black B was removed and 99% of 70 ppm Black B was recovered at pH 2 of the feed phase containing 0.00001 M Na2SiO3, flow rate of 150 ml/min and 0.2 M NaOH. The membrane support also remained stable for up to 36 hours under an optimum condition.
The potential application of Chlorella vulgaris UMACC 001 for bioremediation of textile wastewater (TW) was investigated using four batches of cultures in high rate algae ponds (HRAP) containing textile dye (Supranol Red 3BW) or TW. The biomass attained ranged from 0.17 to 2.26 mg chlorophyll a/L while colour removal ranged from 41.8% to 50.0%. There was also reduction of NH(4)-N (44.4-45.1%), PO(4)-P (33.1-33.3%) and COD (38.3-62.3%) in the TW. Supplementation of the TW with nutrients of Bold's Basal Medium (BBM) increased biomass production but did not improve colour removal or reduction of pollutants. The mechanism of colour removal by C. vulgaris is biosorption, in accordance with both the Langmuir and Freundlich models. The HRAP using C. vulgaris offers a good system for the polishing of TW before final discharge.
In this work, activated carbon was prepared from bamboo waste by chemical activation method using phosphoric acid as activating agent. The activated carbon was evaluated for chemical oxygen demand (COD) and color reduction of a real textile mill effluent. A maximum reduction in color and COD of 91.84% and 75.21%, respectively was achieved. As a result, the standard B discharge limit of color and COD under the Malaysian Environmental Quality act 1974 was met. The Freundlich isotherm model was found best to describe the obtained equilibrium adsorption data at 30 degrees C. The Brunauer-Emmett-Teller (BET) surface area, total pore volume and the average pore diameter were 988.23 m(2)/g, 0.69 cm(3)/g and 2.82 nm, respectively. Various functional groups on the prepared bamboo activated carbon (BAC) were determined from the FTIR results.
Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 +/- 0.01 mm to 2.3 +/- 1.0 mm and the average settling velocity increased from 9.9 +/- 0.7 m h(-1) to 80 +/- 8 m h(-1). This resulted in an increased biomass concentration (from 2.9 +/- 0.8 g L(-1) to 7.3 +/- 0.9 g L(-1)) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study. However, only 62% of color removal was observed. The findings of this study show that granular sludge could be developed in a single reactor with an intermittent anaerobic-aerobic reaction phase and is capable in treating the textile wastewater.
OBJECTIVES: Lung exposures including cigarette smoking and silica exposure are associated with the risk of rheumatoid arthritis (RA). We investigated the association between textile dust exposure and the risk of RA in the Malaysian population, with a focus on women who rarely smoke.
METHODS: Data from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis population-based case-control study involving 910 female early RA cases and 910 female age-matched controls were analysed. Self-reported information on ever/never occupationally exposed to textile dust was used to estimate the risk of developing anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA. Interaction between textile dust and the human leucocyte antigen DR β-1 (HLA-DRB1) shared epitope (SE) was evaluated by calculating the attributable proportion due to interaction (AP), with 95% CI.
RESULTS: Occupational exposure to textile dust was significantly associated with an increased risk of developing RA in the Malaysian female population (OR 2.8, 95% CI 1.6 to 5.2). The association between occupational exposure to textile dust and risk of RA was uniformly observed for the ACPA-positive RA (OR 2.5, 95% CI 1.3 to 4.8) and ACPA-negative RA (OR 3.5, 95% CI 1.7 to 7.0) subsets, respectively. We observed a significant interaction between exposure to occupational textile dust and HLA-DRB1 SE alleles regarding the risk of ACPA-positive RA (OR for double exposed: 39.1, 95% CI 5.1 to 297.5; AP: 0.8, 95% CI 0.5 to 1.2).
CONCLUSIONS: This is the first study demonstrating that textile dust exposure is associated with an increased risk for RA. In addition, a gene-environment interaction between HLA-DRB1 SE and textile dust exposure provides a high risk for ACPA-positive RA.
Mixed dye consists of six commercial dyes and textile effluents from cotton dyeing process were treated by electrochemical-assisted photodegradation under halogen lamp illumination. Two types of effluents were collected which are samples before and after undergone pre-treatment at the factory wastewater treatment plant. The photodegradation process was studied by evaluating the changes in concentration employing UV-vis spectrophotometer (UV-vis) and total organic carbon (TOC) analysis. The photoelectrochemical degradation of mixed dye was found to follow the Langmuir Hinshelwood pseudo-first order kinetic while pseudo-second order kinetic model for effluents by using TOC analyses. The chemical oxygen demand (COD) and biochemical oxygen demand (BOD) values of mixed dye and raw effluents were reported. Photoelectrochemical characteristic of pollutants was studied using the cyclic voltammetry technique. Raw effluent was found to exhibit stronger reduction behaviour at cathodic bias potential but slightly less photoresponse at anodic bias than mixed dye.
A rapid and direct liquid chromatographic (LC) technique is described for the determination of a eutectic mixture of diphenyl oxide and biphenyl such as Dowtherm A thermal heating fluid (THF) in oleochemicals and palm olein. Analysis is performed with an RP-18 column with fluorescence detection (excitation at 247 nm and emission at 310 nm). The isocratic mobile phase (1.0 mL/min) consists of methanol and water (90 + 10, v/v). A linear calibration model (correlation coefficient = 0.9999) was developed directly from used Dowtherm A THF with the biphenyl peak (4.70 min) as a marker. Average recoveries from spiked glycerin, fatty alcohol mixture, methyl ester mixture, fatty acids, and palm olein were 90.9-108.7%, with a detection limit of 0.1 microgram/mL. The technique requires no prior sample cleanup nor extraction steps and is good for quality assurance purposes.
There is an interest in the sustainable utilization of waste cotton cloths because of their enormous volume of generation and high cellulose content. Waste cotton cloths generated are disposed of in a landfill, which causes environmental pollution and leads to the waste of useful resources. In the present study, cellulose nanocrystals (CNCs) were isolated from waste cotton cloths collected from a landfill. The waste cotton cloths collected from the landfill were sterilized and cleaned using supercritical CO2 (scCO2) technology. The cellulose was extracted from scCO2-treated waste cotton cloths using alkaline pulping and bleaching processes. Subsequently, the CNCs were isolated using the H2SO4 hydrolysis of cellulose. The isolated CNCs were analyzed to determine the morphological, chemical, thermal, and physical properties with various analytical methods, including attenuated total reflection-Fourier transform-infrared spectroscopy (ATR-FTIR), field-emission scanning electron microscopy (FE-SEM), energy-filtered transmission electron microscopy (EF-TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results showed that the isolated CNCs had a needle-like structure with a length and diameter of 10-30 and 2-6 nm, respectively, and an aspect ratio of 5-15, respectively. Additionally, the isolated CNCs had a high crystallinity index with a good thermal stability. The findings of the present study revealed the potential of recycling waste cotton cloths to produce a value-added product.
Congo red (CR) is an anionic azo dye widely used in many industries including pharmaceutical, textile, food and paint industries. The disposal of huge amount of CR into the various streams of water has posed a great threat to both human and aquatic life. Therefore, it has become an important aspect of industries to remove CR from different water sources. Molecular imprinting technology is a very slective method to remove various target pollutant from environment. In this study a precipitation polymerization was employed for the effective and selective removal of CR from contaminated aqueous media. A series of congo red molecularly imprinted polymers (CR-MIPs) of uniform size and shape was developed by changing the mole ratio of the components. The optimum ratio (0.1:4: 20, template, functional monomer and cross-linking monomer respectively) for CR1-MIP from synthesized polymers was able to rebind about 99.63% of CR at the optimum conditions of adsorption parameters (contact time 210 min, polymer dosage 0.5 g, concentration 20 ppm and pH 7). The synthesized polymers were characterized by various techniques such as Fourier Infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), Thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX), and Brumauer-Emmett-Teller (BET). The polymer particles have successfully removed CR from different aqueous media with an efficiency of about ~ 90%.
A micro-mesoporous activated carbon (AC) was produced via an innovative approach combining microwave pyrolysis and chemical activation using NaOH/KOH mixture. The pyrolysis was examined over different chemical impregnation ratio, microwave power, microwave irradiation time and types of activating agents for the yield, chemical composition, and porous characteristic of the AC obtained. The AC was then tested for its feasibility as textile dye adsorbent. About 29 wt% yield of AC was obtained from the banana peel with low ash and moisture (<5 wt%), and showed a micro-mesoporous structure with high BET surface area (≤1038 m2/g) and pore volume (≤0.80 cm3/g), indicating that it can be utilized as adsorbent to remove dye. Up to 90% adsorption of malachite green dye was achieved by the AC. Our results indicate that the microwave-activation approach represents a promising attempt to produce good quality AC for dye adsorption.