Dye Wastewater Treatment Research Articles

Comparison of aerobic and anoxic-oxic sequential batch reactors for treating textile wastewater

ABSTRACT The discharge of untreated textile dyeing wastewater containing azo dyes has significant ecological consequences. The incomplete biodegradation of these dyes can produce harmful and carcinogenic aromatic amines (AAs), which pose a threat to the environment. This study evaluates the treatment of real textile dyeing wastewater containing azo dyes by two different systems: an anoxic sequential batch reactor (A/O-SBR) and an aerobic sequential batch reactor (A-SBR). The effects of hydraulic retention time (HRT) on both systems were investigated in terms of chemical oxygen demand (COD), total nitrogen (TN), color, and AAs removal. Ranging between 85% and 92%, the COD removal efficiency was almost similar in the A/O-SBR and A-SBR systems, suggesting that the aerobic phase is primarily responsible for COD removal. However, A/O-SBR showed higher removal of color (90%) than A-SBR (75%) due to the presence of an anoxic phase. HRT has a significant impact on color removal in both systems. However, there was no significant effect on COD removal when HRT exceeded 12 h. According to LC-MS/MS analysis, increasing the HRT from 12 h to 24 h increased the AAs concentration in the anoxic phase, from 253 ng/L to 261 ng/L and slightly decreased the AAs concentration in the aerobic phase from 107 ng/L to 102 ng/L. This resulted in an overall improvement in both dye and AAs removal. The presence of aerobic phase in A/O-SBR and A-SBR demonstrates strong AAs removal capacity. GC-MS/MS analysis indicated that as the HRT of A/O-SBR and A-SBR increased, the number of by-products increased.

Cleanable natural-sugar-alcohol-based polyester membrane for highly efficient molecular separation

Achieving zero discharge of salt-containing dye wastewater is essential for sustainable development, which requires precise separation of organic dyes and inorganic salts. This work describes a new strategy for the preparation of cleanable polyester loose nanofiltration (LNF) membranes using inexpensive natural-sugar-alcohols (erythritol, sorbitol, and maltitol) as aqueous monomers. The resulting polyester membrane has a loose structure with hydrophilic properties and negative charge density. The optimized sorbitol/trimesoyl chloride (TMC) membranes exhibited high pure water permeability (80.63 ± 1.72 L·m−2·h−1·bar−1), a high selectivity factor for salt/dye separation at 229.07(dye rejection of 99.6 ± 0.48%, salt rejection of 8.17 ± 0.8%). Moreover, Sorbitol/TMC polyester membranes exhibit excellent compatibility with dye-fouling detergents, antifouling ability, and long-term stability. The unoptimized erythritol/TMC and maltitol/TMC membranes also exhibit high water permeability and accurate dye/salt sieving ability. The results reveal that natural-sugar-alcohol-based polyester membranes are expected to stand out in the future of salt-containing dye wastewater treatment.

Heterogeneous Fenton treatment of actual textile and dyeing wastewater by α-Cu-FeOOH nanomaterial

This work reports the successful synthesis and application of α-Cu-FeOOH in heterogeneous Fenton treatment of actual textile dyeing wastewater. The material characteristics were analyzed by SEM, EDX, BET, FTIR, and XRD methods. In heterogeneous Fenton tests, the highest TOC and color removal efficiencies were found to be 46.88 and 37.98%, respectively, in the suitable conditions of Cu/Fe molar ratio = 5%, [H2O2] = 0.1 M, [α-Cu-FeOOH] = 0.6 g/L, pH = 7, and after 60 min. The values of color and TOC after treatment well met the discharge standard for textile dyeing wastewater (QCVN 13:2015/BTNMT, Column B). The presence of copper in the material enhanced the activation of H2O2 in heterogeneous Fenton reactions under neutral environments. Therefore, α-Cu-FeOOH material has great potential for practical application in textile wastewater treatment with an initial color of 185.6 mg/L and TOC concentration of 72.54 mg/L.

Preparation and Application of Magnetic Composites Using Controllable Assembly for Use in Water Treatment: A Review.

The use of magnetic composites in wastewater treatment has become widespread due to their high flocculating characteristics and ferromagnetism. This review provides an analysis and summary of the preparation and application of magnetic composites through controllable assembly for use in wastewater treatment. The applications of magnetic composites include the treatment of dye wastewater, heavy metal wastewater, microalgae suspensions, and oily wastewater. Additionally, the recycling and regeneration of magnetic composites have been investigated. In the future, further research could be focused on improving the assembly and regeneration stability of magnetic composites, such as utilizing polymers with a multibranched structure. Additionally, it would be beneficial to explore the recycling and regeneration properties of these composites.

Graphene hydrogel improves S. putrefaciens' biological treatment of dye wastewater: Impacts of extracellular electron transfer and function of c-type cytochromes

Biocompatible materials and biocarriers have attracted great attention in biological wastewater treatment owing to their excellent performance in improving pollutant removal. Graphene-based material, a biocarrier candidate, with excellent adsorbability and conductivity was increasingly applied in anaerobic digestion due to its exceptional potential in the adsorption and electron transfer process. Nevertheless, the green approach for the formation of bio-graphene complexes and their mechanism in dye removal is limited. The aim of this study is to investigate and assess the performance of biological graphene hydrogel (BGH) formed by Shewanella putrefaciens CN32 on the removal of methyl orange (MO) and methylene blue (MB). The results showed that the formation of BGH is determined by the physicochemical characteristics of graphene oxide, including sheet size, oxidation degree, and interlayer distance. BGHs significantly increased the removal efficiency of dyes in comparison to non-graphene samples, with a 24-h removal rate of MO and MB reaching 92.9% and 91%, respectively. The synergetic mechanism of BGH on the enhanced removal rate of organic dye can be ascribed to GO's ability in accelerating extracellular electron transfer and stimulating biodegradation pathways relating to c-type cytochromes, including MtrA and MtrC. These findings provided an understanding of the relationship between graphene-based nanomaterials and Shewanella, which facilitated their future application in environmental biotechnology.

Efficiently elimination of high concentration dye pollutants by Ph-C≡C-Cu/nanoparticles hybrids

For the requirement of industrial printing and dyeing wastewater treatment, this work designed and synthesized a serious of Ph-C≡C-Cu/nanoparticles (NPs) hybrids for highly efficient removal of dye pollutants. Among them, Cu2O/Ph-C≡C-Cu shows the most excellent adsorption ability and considerable stability. The prepared Cu2O/Ph-C≡C-Cu hybrids were detailedly studied, demonstrating a different growth mode of Ph-C≡C-Cu on the surface of Cu2O, which provides increased surface area and adsorption sites exposure. The highest adsorption capacity of MO achieved 629.1 mg/g at 20 wt% Cu2O/Ph-C≡C-Cu hybrid, which is about 10 and 30 time higher than those of raw Ph-C≡C-Cu and Cu2O. Moreover, it is even 3 times higher than the famous adsorbent activated carbon. This is because that the adsorption mode of MO on the surface of Cu2O/Ph-C≡C-Cu hybrid is demonstrated to be chemical adsorption by the kinetic analysis, while it is mainly physical adsorption on the surface of activated carbon. Besides, Cu2O/Ph-C≡C-Cu hybrid also shows good stability and universality at the condition of basic room temperatures (0–50 °C), pH of 5–11, anions (NO3− and HCOO−) and other dyes (congo red, malachite green and sunset yellow) co-existence. This work indicates that 20 wt% Cu2O/Ph-C≡C-Cu is an effective and prospective adsorbent for treating the printing and dyeing industrial wastewater.

Integrating reverse osmosis and forward osmosis (RO-FO) for printing and dyeing wastewater treatment: impact of FO on water recovery.

Reverse osmosis (RO) alone has low water recovery efficiency because of membrane fouling and limited operating pressure. In this study, a combined reverse osmosis-forward osmosis (RO-FO) process was used for the first time to improve the water recovery efficiency of secondary effluent in printing and dyeing wastewater. The effects of operating pressure and pH on water recovery and removal efficiency of RO-FO were investigated. The results showed that the optimum conditions were an operating pressure of 1.5 MPa and a feed solution pH of 9.0. Under optimal operating conditions, most of the organic and inorganic substances in the wastewater can be removed, and the rejection of total organic carbon (TOC), Sb, Ca, and K were 98.7, 99.3, 97.0, and 92.7%, respectively. Fluorescence excitation-emission matrices coupled with parallel factor (EEM-PARAFAC) analysis indicated that two components (tryptophan and tyrosine) in the influent were effectively rejected by the hybrid process. The maximum water recovery (Rw, max) could reach 95%, which was higher than the current single RO process (75%). This research provided a feasible strategy to effectively recover water from printing and dyeing wastewater.

Expansion of carbon source utilization range of Shewanella oneidensis for efficient azo dye wastewater treatment through co-culture with Lactobacillus plantarum.

Shewanella oneidensis has demonstrated excellent potential for azo dye decolorization and degradation. However, in anaerobic environments, S. oneidensis has a narrow carbon source spectrum, which requires additional electron donors, such as sodium lactate. This increases the practical application costs for wastewater treatment. Here, we aimed to expand the carbon source utilization range of S. oneidensis FJAT-2478 by co-culturing it with Lactobacillus plantarum FJAT-7926, leveraging their commensalism relationship to develop a metabolic chain. Results showed that a 1:2 initial ratio of L. plantarum FJAT-7926 to S. oneidensis FJAT-2478 achieved a 97.16% decolorization rate of methyl orange when glucose served as the sole carbon source. This co-culture system achieved a decolorization rate comparable to that obtained using sodium lactate as an electron donor and was significantly higher than that achieved by L. plantarum FJAT-7926 (7.88%) or S. oneidensis FJAT-2478 (6.89%) alone. After undergoing five cycles, the co-culture system continued to exhibit effective decolorization. It was demonstrated that the co-culture system could use common and inexpensive carbon sources, such as starch, molasses, sucrose, and maltose, to decolorize azo dyes. For instance, 100mg/L methyl orange could be degraded by over 98.05% within 24h. The results indicated that the degradation rates of methyl orange were higher when L. plantarum was inoculated first, followed by a subsequent inoculation of S. oneidensis after 2h. The co-culturing of L. plantarum FJAT-7926 and S. oneidensis FJAT-2478 proved to be an effective strategy in treating azo dye wastewater, expanding the potential practical applications of S. oneidensis.

Effect of the Standardized ZnO/ZnO-GO Filter Element Substrate driven Advanced Oxidation Process on Textile Industry Effluent Stream: Detailed Analysis of Photocatalytic Degradation Kinetics.

A simple process of synthesizing coated filter element substrates (FES) containing zinc oxide (ZnO) nanorods and ZnO graphene-oxide nanocomposite for a pilot-scale industrial dye-effluent treatment plant is proposed. This work reports a detailed analysis of the photocatalysis mechanism on real industrial effluent streams containing a mixture of dyes. The analysis is very relevant for conducting advanced oxidation process-assisted effluent remediation at a field-level treatment operation. Estimation of the dye concentration shows nearly complete (≥98%) degradation from an initial dye sample concentration. A detailed study for the analysis of the initial reactive dyes and their degradation products was performed for quantification and identification of the degradation products through various spectral techniques. A design of the remediation mechanism through degradation pathways is proposed for characterizing the organic compounds in the degraded dye products. A regeneration and reusability study was performed on the FES presenting the durability of the FES-designed synthesis process originally for 11 cycles and regenerated FES for six cycles for achieving a threshold of 60% degradation efficiency. The experimental results demonstrate the efficacy of FES through the designed immobilized approach for the complete remediation of textile dye effluents for a 4 h treatment plant process and the consistent operability of the FES for the combined dye wastewater treatment operations.

Adsorption of Amido Black 10B by Zinc Ferrite and Titanium Dioxide

This study focuses on the comprehensive recycling and utilization of zinc ferrite, a by-product of wet zinc refining, for the treatment of azo dye wastewater. It explores the adsorption performance of various materials on Amido Black 10B and analyzes the factors that influence the adsorption process. Zinc ferrite derived from the by-products of wet zinc refining, zinc ferrite synthesized via calcination, and titanium dioxide prepared using the sol–gel method are utilized as adsorbents, specifically targeting Amido Black 10B. By adjusting factors such as calcination temperature, mixing ratio, initial pH, adsorbent dosage, adsorption time, initial concentration, and reaction temperature, the effects on the adsorption of Amido Black 10B are studied. Additionally, the performance of composite materials consisting of different crystalline forms of titanium dioxide and purified zinc ferrite is examined. Furthermore, the adsorption process of Amido Black 10B by purified zinc ferrite/titanium dioxide is analyzed in terms of kinetics and thermodynamics. The results show that titanium dioxide and purified zinc ferrite, prepared at temperatures of 300 °C to 550 °C, achieve over 90% removal efficiency when co-adsorbing Amido Black 10B. The best performance is observed at a ratio of 4:6 for purified zinc ferrite to titanium dioxide, with removal efficiency exceeding 80%. The second-order kinetic model fits the adsorption data well, and higher initial solution concentrations lead to decreased adsorption rates. The adsorption process of purified zinc ferrite/titanium dioxide on Amido Black 10B is spontaneous, exothermic, and reduces system disorder. Higher temperatures negatively impact the adsorption process.

Carboxylated cellulose-based aerogel with cellular pores prepared by stir freezing for cationic dye adsorption

A TEMPO-oxidized cellulose (TOC)/nanofiber cellulose (NFC) biomass aerogel was prepared through freeze-drying (FD) for cationic dye adsorption. The stir freezing method was utilized to build cellular pores so as to improve the mechanical property of aerogel. The dielectric-assisted microwave (MW) heating was adopted to increase the FD rate. The results showed that the proposed method could simultaneously intensify the mass and heat transfer of FD, reducing more than 36% of drying time. The TOC/NFC aerogel exhibited a high mechanical property with 91.36 kPa of compressive stress at 80% strain. The maximum adsorption capabilities of aerogel prepared by stir freezing for methylene blue (MB) and malachite green (MG) dyes were 248.27 and 227.30 mg·g–1, respectively. The prepared aerogel showed high selective adsorption of cationic dyes in binary dye solutions. Moreover, the prepared aerogel exhibited a satisfactory recycling performance in 20 cycles of adsorption/desorption experiments. This work provides a new freezing and FD strategy to prepare TOC/NFC aerogels with promising applications in industrial printing and dyeing wastewater treatment.

2D/2D MoS2/ZnIn2S4 heterojunction for simultaneous realization of solar water evaporation and photocatalytic dye degradation

Solar-powered interfacial water evaporation technology coupled with photocatalytic function is considered as a promising solution to achieve the dye wastewater purification and solve the problem of organic pollution’s enrichment on traditional solar absorbers. In this study, a two-dimensional (2D) MoS2/ZnIn2S4 composite was designed by a two-step hydrothermal method, and served as a solar absorber with a water evaporation rate of 1.54 kgꞏm−2ꞏh−1. The deposition of ZnIn2S4 on MoS2 endowed the composite with 98.7% of photodegradation efficiency for dye wastewater via the construction of type Ⅰ heterojunction and avoided the problem of secondary pollution of dye wastewater. This study successfully integrated photocatalysis into the cutting-edge solar-driven interfacial evaporation system, accomplishing the expansion of multifunctional solar absorber and extending the application for the treatment of dye wastewater with zero wastewater discharge.

Performance and response of coupled microbial fuel cells for enhanced anaerobic treatment of azo dye wastewater with simultaneous recovery of electrical energy.

The anaerobic baffled reactor (ABR) is an anaerobic bioreactor that uses baffles to separate the working area into multiple reaction zones. The ABR-microbial fuel cell (MFC) reactor was constructed by embedding MFC in each reaction zone of the ABR. Its degradation of azo dye type (acid mordant red) wastewater and microbial power generation performance were investigated. For different electrode area ratios, the best enhanced treatment and electrical energy output of the coupled system was achieved with an anode/cathode area ratio of 1:1. Compared with the electrode area ratio of 2:1 and 1:2, the power density increased by 82.5% and 80.6%, and the Coulomb efficiency increased by 133.3% and 64.7%. In addition, the best enhanced treatment of printing and dyeing wastewater was achieved by ABR-MFC at 1:1. At a dye concentration of 200 mg/L and a sucrose concentration of 1000 mg/L, the coupled system obtained a COD removal of 92.85% and a chromaticity removal of 96.2%, which achieved a relative COD and chromaticity removal improvement of 1.82% and 2.64%, respectively, relative to the ABR. Scanning electron microscopy (SEM) observation of the electrodes at 1:1 revealed that more microorganisms were attached to the anode surface of the coupled system, the particle size of the granular sludge within the system was larger, and the UV scanning pattern showed lower dye concentration in the water. In conclusion, the microbial fuel cell enhanced anaerobic treatment of dyeing wastewater was the most effective when the electrode area ratio was 1:1, and the best electrical energy output was obtained at the same time. ABR-MFC provides a new idea for the enhanced treatment of dyeing wastewater and electrical energy production.

Fabrication of engineered biochar-iron oxide from date palm frond for the effective removal of cationic dye from wastewater

Wastewater containing dye is harmful to the environment. Methylene blue (MB) dye can be removed from wastewater using low-cost, renewable adsorbents. In this study, modified biochar (Biochar-FexOy), pristine biochar and FexOy were fabricated, characterized, and investigated for their performance to remove MB dye from wastewater. The Biochar-FexOy (85.1 mg/g) showed increased adsorption capacity in comparison to biochar (60.1 mg/g) and FexOy (50 mg/g) at an optimum pH of 8 due to the increase in surface area, porosity, and deposition of metal ions on its surface for adsorption. The enhanced MB adsorption by the Biochar-FexOy can be attributed to electrostatic attraction, hydrogen bonding, π-π interactions, and possible cationic exchange as evidenced by the result of the FTIR, EDX, and XRD analysis. Moreover, the adsorption of MB dye by the Biochar-FexOy showed an antagonistic effect in the presence of NaHCO3− and NaCl salt but showed a synergistic effect in the presence of Cu (II) ions. The Langmuir and pseudo-second-order isotherm model best describe the adsorption process of MB dye over the Biochar-FexOy. The adsorption capacity was still high after 4 regeneration cycles for the Biochar-FexOy which concludes that modified biochar can be effectively utilized for dye wastewater treatment. Finally, the fixed-bed column adsorption performance demonstrated that Biochar-FexOy could be used to polish real secondary textile industry effluents prior to treatment.

Constructed "sandwich" structure to obtain recyclability and high rejection rate high-flux CA@HMSN@h-BN/PDA membrane for efficient treatment of dye wastewater

It is necessary to develop a nanofiltration membrane that can remove dye molecules efficiently and is not easily polluted for the treatment of textile industry wastewater. A novel high-flux CA@HMSN@h-BN/PDA membrane with a "sandwich" structure was obtained by assembling the support layer of the Hollow mesoporous silica nanoparticles (HMSN), and the isolation layer of the h-BN/PDA on the Cellulose acetate (CA) membrane. HMSN was synthesized using ZIF-8 as a self-sacrificial template to provide improved permeability. h-BN/PDA obtained by modifying hexagonal boron nitride (h-BN) with polydopamine (PDA) brought higher hydrophilicity, rejection rate, and stability to the membrane. The study solved the problem that the membrane separation process requires sacrificing flux and recyclability for high rejection rates. CA@HMSN@h-BN/PDA membrane has a super-hydrophilic property (water contact angle of 22.5°) and high pure water flux (4419.4 L·m−2·h−1·bar−1). Meanwhile, the CA@HMSN@h-BN/PDA membrane achieves a high rejection rate (over 99.5%) due to the special "sandwich" structure. Through cycling experiments, CA@HMSN@h-BN/PDA membranes exhibit recyclability. More importantly, CA@HMSN@h-BN/PDA membranes maintain stable performance in complex environments, such as extremely acidic/alkaline or inorganic salt interference environments. Thus the CA@HMSN@h-BN/PDA membrane has the potential for future wastewater treatment.

Upcycling polyvinyl chloride waste into highly efficient amine-functionalized nanofiber membrane adsorbent through the dissolution-modification-reforming process

Polyvinyl chloride (PVC) waste recycling is a challenging task and there is a great lack of convenient, feasible, and effective methods. In this work, a dissolution-modification-reforming process was proposed to upcycle PVC into highly efficient adsorbents (polyethylenimine-crosslinked PVC nanofiber membranes (PEI/PVC NFMs)). The effect of PEI to PVC mass ratio on the preparation of PEI/PVC NFMs was estimated. The adsorption performance of azo dyes on PEI/PVC NFMs was evaluated using Reactive Black 5 (RB5). The acid/alkali resistance of PEI/PVC NFM and its adsorption potential for various ionic pollutants were also investigated. Here are the results: The PEI/PVC NFMs exhibited high RB5 uptake within pH 2 to 8. The amine groups content in PEI/PVC NFM increased with increasing of PEI to PVC mass ratio, resulting in faster adsorption rates and higher adsorption capacity. With the mass ratio of PEI to PVC increased from 0.5:1.0 to 2.0:1.0, the adsorption equilibrium time reduced from 480 to 120 min, while the maximum RB5 uptake increased from 314.5 to 1036.7 mg/g. The adsorption isotherms and thermodynamic analysis revealed that physisorption dominated the adsorption process. The PEI/PVC NFM also exhibited good adsorption potential for various ionic pollutants, including per-/poly-fluoroalkyl substances (PFAS) and heavy metals (Pb2+, H2AsO4−, Co2+, and Ni2+). The 30-d acid/alkali resistance test confirmed that the PEI/PVC NFM has better stability at higher pH conditions. The PEI/PVC NFM exhibited good recyclability in azo dye wastewater treatment. In conclusion, this study demonstrates that the dissolution-modification-reforming process is a viable route for PVC waste upcycling. This pathway allows the conversion of PVC waste into highly efficient adsorbents for the elimination of ionic pollutants from water.

Antifouling and Chemical-Resistant Nanofiltration Membrane Modulated by a Functionalized MWCNT Interlayer for Efficient Dye/Salt Separation at High Salinity.

Dye/salt separation in textile wastewater is of great importance. Membrane filtration technology is an environmentally friendly and effective approach to solve this issue. In this study, a thin-film composite membrane with a tannic acid (TA)-modified carboxylic multiwalled carbon nanotube (MWCNT) interlayer (M-TA) was prepared by interfacial polymerization with amino-functionalized graphene quantum dots (NGQDs) acting as aqueous monomers. The addition of the M-TA interlayer favored the formation of a thinner, more hydrophilic, and smoother selective skin layer for the composite membrane. The pure water permeability of the M-TA-NGQDs membrane was ∼9.32 L m-2 h-1 bar-1, which was higher than that of the NGQDs membrane without the interlayer. Meanwhile, the M-TA-NGQDs membrane presented better methyl orange (MO) rejection (97.79%) than the NGQDs membrane (87.51%). The optimal M-TA-NGQDs membrane exhibited excellent dye rejection (Congo red (CR): 99.61%; brilliant green (BG): 96.04%) and low salt rejection (NaCl < 15%). Noticeably, the M-TA-NGQDs membrane displayed effective selective separation performance (CR and BG > 99%) for dye/NaCl mixed solutions even at a high NaCl concentration of 50,000 mg/L. Furthermore, the M-TA-NGQDs membrane presented high water permeability recovery ratio values (91.02-98.20%). Importantly, the M-TA-NGQDs membrane showed excellent chemical stability (acid/alkali resistance). Generally, the fabricated M-TA-NGQDs membrane exhibited a great prospect for applications in dye wastewater treatment and water recycling, especially for the effective selective separation of dye/salt mixtures for high-salinity textile dyeing wastewater.

Adsorption and Degradation of Methylene Blue Aqueous Solution by Fe‐based Amorphous Alloy

Fe‐based amorphous ribbons with the brand name 1K101 can adsorb methylene blue (MB) solution. The adsorption reaction is multilayer adsorption, in which chemical adsorption plays a major role. There are also some processes like physical adsorption, liquid phase diffusion, and internal diffusion of particles. The adsorption reaction is exothermic and spontaneous, which is more favorable at low temperatures. During the adsorption process, the entropy value decreases, the degree of disorder and freedom of the solution decreases, and the structure also changes. What's more, H2O2, pH, ribbons's dosage, dye's concentration, and temperature affect the degradation performance of 1K101 on MB. Degradation reactions are mainly controlled by surface chemical reactions, including chemical reduction reactions and adsorption. When c(H2O2) is 15 mm, pH is 2, ribbons’ dosage is 0.9 g, c(MB) is 20 mg L−1, temperature is 338 K, the degradation effect is the best. The optimal conditions with lowest overall cost obtained under the orthogonal experiment are: c(H2O2) = 20 mm, pH = 2, ribbons's dosage = 0.7 g, c(MB) = 20 mg L−1, and T = 338 K. Overall, 1K101 amorphous ribbon can be utilized to treat MB solution, and its degradation effect is better than adsorption effect, which can provide new ideas for the reuse of waste amorphous ribbon and the treatment of azo dye wastewater.

Utilization of Agricultural Waste as Low-Cost Adsorbents in Dye Wastewater Treatment: Kinetic and Thermodynamic Study

In recent years, the treatment of dye wastewater has attracted more attention because of its harmful impact on the environment. Therefore, dye wastewater should be treated using effective treatment methods, such as adsorption, which is widely employed to remediate many dyes from wastewater. This work studied the use of Laurus Nobilis Leaves (LNL) and sawdust (SD) as low-cost natural adsorbents to remediate reactive blue (RB) dye from synthetic wastewater under the influence of their dosages (0.5-5.5 g) for each, pH (3-9), and contact time (10-190 min). The experimental design, analysis of results, and optimization were conducted using Response Surface Methodology (RSM) based on Box-Behnken method (BBM) and the Minitab-Statistical program. The BET and FT-IR tests have been used to characterize these adsorbents, which show that SD-adsorbent includes more pore volume and surface area than LNL-adsorbent. The adsorption isotherms study revealed that Langmuir isotherm was a more fitted model than Freundlich model. Adsorption kinetic shows that the current adsorption process obeys the pseudo-second order model (R2=0.998) compared to the pseudo-first order model (R2=0.973) and the intraparticle diffusion model (R2=0.915). Thermodynamics study revealed that the present adsorption is endothermic, random irregularity at the solid-liquid, and a spontaneous nature. More than 60% of RB-dye removal efficiency was achieved at the optimal conditions, which were 5.5 g of SD-adsorbent, 0.8 g of LNL-adsorbent, pH 3, and 141 min of the contact time. The core results proved that the interaction effect of using multi-natural adsorbents was significant and cost-effective, providing considerable removal of dye from wastewater.

Drying of Artocarpus Heterophyllus and is application in treating dye wastewater

Coagulation is a common technique used in wastewater treatment plants to remove dissolved chemicals, turbidity, and colours. Aluminium sulphate (alum), the most common coagulant, has recently been connected to both Alzheimer’s disease and environmental issues. In order to deal with these issues, researchers are considering the possibility of developing a natural coagulant that is safe for both humans and the environment. In this research, Artocarpus Heterophyllus (Jackfruit) seeds were used to make a natural coagulant, and their use in the treatment of coloured wastewater was implemented. This study examined the effects of hot air-drying temperatures on the Jackfruit seed moisture content. Jackfruit seed application in dye wastewater treatment was also optimised via several experiments with varying coagulation parameters generated via central composite response surface design (CCD). Jackfruit seed drying and protein extraction are two crucial steps in making natural coagulants. Jackfruit seeds were dried in an oven at 40°C, 50 °C and 60°C to collect drying data. Drying information for the optimum air-drying temperature that produces the shortest drying time was used to generate five drying kinetic models. Based on the results of this research, 60°C hot air-drying temperature was chosen as the optimal drying temperature for Jackfruit seeds, resulting in the shortest total drying time of just 5 hours. Once the optimum hot air-drying temperature was recorded, five thin drying kinetic models were used to determine which module best explained the drying kinetics at the optimum hot air-drying temperature. Microsoft Excel solver was used to calculate the values of X2, R2, and RMSE. The kinetic model with the lowest X2 and RMSE was selected. The modified Midilli model was chosen as the best kinetic model for representing the drying performance of Jackfruit seeds, as it had the lowest X2 and RMSE. After that, the protein was extracted from jackfruit seeds that had been dried at 60°C for 5 hours. In order to extract the protein from jackfruit seeds, 2 g of dry seeds were dissolved in 100 mL of distilled water, blended, and filtered before being used in the Jar test. The initial concentration of dye wastewater, the pH of the wastewater, and the coagulant dosage were the main parameters in the jar test. Maximum colour removal of 85.81% was attained during Jackfruit seed-based dye wastewater treatment when the initial concentration of dye wastewater was 400 ppm; the coagulant dosage was 100mg/L, and the pH was 2. Therefore, these were chosen as the optimum parameters for treating dye wastewater with Jackfruit seeds.