Optimization of operating parameters in the removal of textile dyes by electrocoagulation

In the waste water treatment, especially in the removal of textile dyes from aqueous media, it is known that photocatalytic oxidation technique has tremendous advantages compared to conventional techniques, such as quick oxidation, prevention of polycyclic end products, and oxidation of organic species even at µg/L concentrations. Heterogeneous photocatalysis consisting semiconductor oxides such as TiO 2 has been effectively implemented in aqueous media. However, problems such as catalyst separation and catalyst recovery are encountered when powder catalysts are used. Meanwhile, the fixation of oxides by any method reduces the catalytic effıciency. In this study, nanoparticles (10-100 nm) as heterogeneous catalysts were synthesized and then immobilized onto cross-linked polymer carriers that are able to swell in aqueous media in order to increase photocatalytic activity to the highest level. It has been seen that the removal of textile dyes is possible by means of nanoparticles immobilized onto cross-linked polymer carriers. The performance of photocatalyst was evaluated in the removal of reactive textile dye (Acid Red 14) from aqueous media.

This study evaluates the removal of textile dyes using mixed adsorbents prepared by the growth of Aspergillus niger in orange peels. The highest azo dye removal efficiency was obtained at pH 2, solid: liquid ratio (1: 4 g·mL-1) and time of equilibrium of 250 minutes for each dye. The concentrations of Remazol Black B (RB) and Remazol Red (RR) in both synthetic textile effluents were between 25 mg·L-1 and 100 mg·L-1. The mixed adsorbent was characterized by X-ray diffraction (XRD), spectroscopy infrared region (FTIR) and scanning electron microscopy (SEM). The results indicated that there was a 100% removal of RB and 94.85% of RR at the concentration of 25 mg·L-1. At the concentration of 100 mg·L-1, the percentages of removal reached 98.87% for RB and 96.37% for RR, respectively. The proposed mixed adsorbent was able to remove the textile dyes, presenting adsorptive capacities of 20.77 mg·g-1 and 19.28 mg·g-1 for the dyes RB and RR. Regarding the adsorption kinetics, the experimental data showed that the pseudo second order model was the one that best explained the adsorptive process. For the equilibrium results, the Langmuir model and the Langmuir-Freundlich model were the ones that best fit the experimental data of RB and RR, respectively. The mixed adsorbent produced is a promising alternative for the treatment of textile effluents.

The study assesses the performance of experimental wetland pond systems vegetated by Lemna minor L. (common duckweed or lesser duckweed) for textile azo dye removal. The objectives are to assess the influence of L. minor on water quality parameters, compare the dye and chemical oxygen demand (COD) removal of four dyes (Acid Blue 113, Reactive Blue 198, Direct Orange 46 and Basic Red 46) with each other, and monitor the effect of dye accumulation as a function of the relative growth rate (RGR) of L minor. Findings indicate that the simulated shallow pond systems remove BR46 (low concentration) significantly (p < 0.05) higher than other dyes, and the ponds containing L. minor outperformed control ponds by around 51% in mean removal efficiency with a potential of L. minor for phytoremediation of approximately 13% efficiency.

Carboxymethyl β-cyclodextrin–nanochitosan–glutaraldehyde (CM-βCD:nChi:Glu) terpolymer was prepared as a nano-adsorbent for the removal of the anionic textile dye, acid red 37. The terpolymer nanocomposite formation and characterization were clarified by FTIR, XRD, scanning electron microscopy, TEM, Brunauer–Emmett–Teller specific surface area (BET-SSA), and zeta potential. The removal of the textile dye was investigated by using the batch adsorption method, investigating the effect of pH, dye concentration, adsorbent dose, contact time, and temperature. The results revealed that the maximum removal efficiency of 102.2 mg/L of the dye is about 99.67% under pH 6.0, the optimal contact time is 5 min, and the adsorbent dosage is 0.5 g/L. At 29°C; the adsorption capacity increased from 81.29 to 332.60 mg/g when the initial concentration of the dye was increased from 40.97 to 212.20 mg/L. Adsorption kinetics fitted well with the pseudo–second-order model with a good correlation (R2 = 0.9998). The Langmuir isotherm model can best describe the adsorption isotherm model. Based on the experimental results, the CM-βCD:nChi:Glu terpolymer has a promising potential as an efficient novel adsorbent for the removal of textile dye acid red 37 from contaminated water. This study’s preparation techniques and demonstrated mechanisms offer valuable insights into the adsorbent–adsorbate interactions mechanism, analysis, challenges, and future directions of beta-cyclodextrin/chitosan–based adsorbents in wastewater treatment.

The existence of dye effluent in environmental water bodies is becoming a growing concern to environmentalists and civilians due to negative health effects. In this study, a novel poly(acrylonitrile)-membrane-supported carbon-doped titanium dioxide–coal fly ash nanocomposite (C-TiO2-CFA/PAN) was prepared and evaluated in the removal of textiles dyes (methyl orange and golden yellow) in water. The C-TiO2-CFA nanocomposite was prepared via sol-gel synthesis and immobilized on PAN membrane prepared via phase inversion technique. The photocatalyst was characterized by FTIR, XRD, BET surface area analysis, SEM, EDX, and DRS. FTIR analysis confirmed the existence of the expected functional groups, and XRD revealed that the C-TiO2 was predominantly in the anatase phase, which exhibited the highest photocatalytic activity. The optimum C-TiO2-CFA photocatalyst load on the PAN membrane was 2% w/w, and it achieved degradation efficiencies of 99.86% and 99.20% for MO and GY dyes, respectively, at pH 3.5, using a dye concentration of 10 ppm, under sunlight irradiation, in 300 min. The novel 2% C-TiO2-CFA/PAN photocatalytic membrane proved to be very effective in the removal of textile dyes’ water. Three reusability cycles were carried out, and no significant changes were observed in the photocatalytic efficiencies. Immobilization on PAN membrane allowed easy recovery and reuse of the photocatalyst.

Removal of dyes from an artificial textile dye effluent by two agricultural waste residues, corncob and barley husk

Removal of dyes from colored textile wastewater by orange peel adsorbent: Equilibrium and kinetic studies

This research was conducted to produce nanofiltration (NF) membranes, which have good performance in terms of removal of textile dye (Reactive Red 120, RR120) from simulated wastewater as one of several eco-engineering developments for sustainable water resource management. Phase inversion technique was utilized to fabricate the membrane with polysulfone (PSF) support, dissolved in N-methyl-2 pyrollidone (NMP) solvent, and diethylene glycol (DEG) as non-solvent additive. The fabricated membrane then modified with the additional of dopamine coating and further modified by interfacial polymerization (IP) to form a thin film composite (TFC)-NF membrane with PSF substrate. TFC was formed from interaction between amine monomer (2 %-weight of m-phenylenediamine (MPD) in deionized water) and acyl chloride (0.2 %-weight of trimesoyl chloride (TMC) in hexane). From this study, the fabricated PSF-TFC membrane could remove dyestuff from RR120 wastewater by 88% rejection at 120 psi. The result of this study is promising to be applied in Indonesia where researches on removal of dyes from textile wastewater by using membranes are still quite rare. Therefore, this paper may open new avenues for development of eco-engineering development in Indonesia.

The seed extracts of Moringa oleifera has been studied as alternative coagulating agent to chemicals commonly used in order to minimize costs while reducing environmental impacts and human health arising from traditional processes of wastewater treatment. This work studied the performance of the aqueous extract of Moringa oleifera seed in the removal of four different types of textile dyes classified as dispersed, acidic, basic and reactive. Studies with aqueous and saline solutions were performed aiming to improve performance in the removal of textile dyes, and stability testing on the storage time of the extract of Moringa oleifera. Studies were performed using spectrophotometric analysis by means of calibration curves of textile dyes in an aqueous medium.The results showed that the seed extract of Moringa oleifera was quite efficient in the removal of textile dyes, except for the cationic type. Regarding the behavior of textile dyes in aqueous solution and the saline extract were not found significant differences in terms of removal. Other promising results were obtained to evaluate coagulant activity of the extract up to three days storage at room temperature. This fact is important from the operational aspect arising from the use of the extract on a large scale: the possibility to prepare a larger amount of extract, without loss of coagulant activity may enable the utilization of this resource

Dead fungal biomass prepared from Phanerochaete chrysosporium and Funalia trogii was tested for their efficiency in removal of textile dyes. The effects of contact time, initial dye concentration, amount of dead biomass and agitation rate on dye removal have been determined. Removal of all dyes required a very short time (60 min). Experimental results show that, P. chrysosporium was more effective than F. trogii . An increase in the amount of dead biomass positively affected of the dye removal. The removal efficiency of different amount of biomass was in order 1 g > 0.5 g > 0.2 g > 0.1 g. The highest removal was obtained at 150-200 rpm. Slightly lower removing activities were found at lower agitation rates. This study showed that it was possible to remove textile dyes by dead biomass of P. chrysosporium .

Organic synthetic dyes are widely used in textile industry. The presence of dyes in the effluents is a major concern due to their effect on health and environment. Thus, these pollutants must be removed from wastewaters by appropriate treatments before their evacuation. In this regard, much attention has recently been paid to dried plants as low cost biomaterials. In the present study, we aimed to investigate the removal of Congo red dye (CR) from aqueous solutions by Carpobrotus edulis plant as natural adsorbent using batch adsorption technique at room temperature. The effect of contact time, pH, dye concentration, and adsorbent dose on the removal of dye was also studied. The experimental data were analyzed by using mathematical models to determine the thermodynamic parameters. The negative values of free energy change indicated the spontaneous nature of the adsorption and negative value of enthalpy change suggested the exothermic nature of the adsorption process. The characterization of the dried plant was studied by using different methods such as; BET method, SEM‐EDX and Elemental analysis techniques. Overall the results of the present study show that C. edulis plant can be successfully used for removal of anionic textile dyes from industry effluents.

This chapter provides extensive information on the removal techniques of dyes and heavy metals using biopolymers and biocomposites. Adsorption method was used for the removal of heavy metals in wastewater, in which activated carbons and biopolymers were used as common adsorbents. Biopolymers are polymers produced by living organisms, and they are polymeric biomolecules. Biocomposites are composite materials and a reinforcement of natural fibers. Heavy metals are transported by runoff water and contaminate water sources downstream from the industrial site. Different types of industrial wastewaters contain different types of heavy metals. Heavy metals from inorganic effluents have been removed using conventional treatment processes, including chemical precipitation, coagulation, complexation, activated carbon adsorption, ion exchange, solvent extraction, foam flotation, electro-deposition, cementation, membrane operations, and electro-remediation methods. Many investigators have tried various methods for the removal of heavy metals and textile dyes from industrial wastewater.

Nowadays, the extraction of textile dyes from the wastewater in industry becomes an environmental worldwide issue. Water contamination is a big threat of not only for state of the environment but human body causes some chronic diseases. Textile dyes are worn to several types of products by fabrication, for paper, leather, plastic and some products, used in human daily life. Despite of containing various hazardous chemicals into textile dyes, it is necessary to be discharged from effluents of waste-water of industry through treatment as quick as possible. A number of technologies of different processes are effectively carried out for the treatment of industrial waste water by removal of colors. A variety of textile dyes is having different chemical structure with different properties dealing with the activity of industrial reaction. By reviewing of effects of textile dyes such as toxicity and mutagenicity, bacteria and organism embedded a prologue of the expulsion of metals to the environment. Certainly, for the dominion of textile dyes removal, adsorption can be regarded as effective method used by activated carbon, bentonite clay as adsorbent for the wastewater treatment in industry. Predominantly, it is a critical review of literature conferred the removal of textile dyes for the treatment of industrial wastewater by using techniques, technologies, adsorbents thoroughly. Certainly, Adsorption is the sole and ultimate approach for removal of textile dyes through the industrial wastewater treatment. This literature shows the feasibility of minimum cost adsorbent in term of maximum outcome of industrial wastewater treatment for textile dyes removal.

Two textile dye (indigo carmine and acid blue 25) were removed using activated carbon (AC) as solid adsorbent. Effects of various parameters such as adsorbent dosage, contact time, kinetics and thermodynamic properties were investigated by batch adsorption technique. The results shown that the adsorption kinetics of textile dye was determined by the pseudo-second order model and adsorption isotherms fitted very well with Langmuir model. In addition, thermodynamic properties indicated that the adsorption of both textile dye on AC were endothermic and spontaneous process. The maximum adsorption capacities (qm) of indigo carmine and acid blue 25 onto AC was 89.29-104.17 mg/g and 1,428.00-2,000.00 mg/g, respectively. This results could be explained by stronger interaction between acid blue 25 and AC. This work indicated that AC can be used as an alternative adsorbent for removal of textile dye especially acid blue 25, due to the low cost and high efficiency of adsorption capacity. Keywords: textile dye, adsorption, kinetics, activated carbon

Chapter 15 - Advanced modeling of a textile dye removal from wastewater by a sulfate radical-based AOP using an artificial intelligence-based optimization approach