Industrial Effluents Research Articles

Selenocyanate removal using combined system of TiO2- photocatalysis and Fe(III)/SiO2 adsorption {UV-TiO2/[Fe(III)/SiO2]}: Complex destruction and simultaneous selenium species adsorption

Selenocyanate (SeCN‾) species, commonly found in industrial effluents from crude oil refineries and mining operations, present substantial health risks to humans and animals. This study investigates the treatment of selenocyanate-contaminated streams using a combination of TiO2 photocatalysis and Fe(III)/SiO2 binary oxide adsorption {UV-TiO2/[Fe(III)/SiO2]}. The Fe(III)/SiO2 binary oxide was synthesized and characterized using X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. XRD analysis revealed non-crystalline Fe-oxide phases, while FTIR indicated the presence of various Fe and O functional groups on the Fe(III)/SiO2 surface. Adsorption studies using Fe(III)/SiO2 showed its selenocyanate uptake capacity ∼ 2.1 mg/g, with the respective data closely aligning with the Langmuir isotherm model. This Fe(III)/SiO2 adsorption feature was successfully combined in the {UV-TiO2/[Fe(III)/SiO2]} system in which the hydroxyl radicals (●OH) generated by the UV-TiO2 facilitated the breakdown of the selenocyanate complex, while the resulting selenite and selenate were simultaneously adsorbed by the Fe(III)/SiO2 within a 240-min reaction time. A mathematical model developed using a face-centered central composite design-response surface methodology (FCD-RSM) showed significant predictive capability with an insignificant lack of fit. Optimal conditions for selenium removal were determined to be 20 mg/L selenocyanate, 1 g/L TiO2, and 1 g/L Fe(III)/SiO2, at pH 5, within a 240-min reaction time. Kinetic analysis demonstrated that selenocyanate degradation followed pseudo-first-order kinetics, while total selenium removal adhered to pseudo-second-order kinetics, confirming the proposed selenium species removal mechanism. Overall, this integrated approach offers a promising solution for effective selenocyanate remediation in industrial wastewater.

Methylene blue adsorption by chemical-activated Trichanthera gigantea leaf

ABSTRACT This study investigated the potential of NaOH-treated Trichanthera gigantea leaf (TGL) powder as a sustainable, low-cost biosorbent for methylene blue (MB) removal from wastewater. Characterization using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller, and energy-dispersive X-ray spectroscopy (EDX) techniques confirmed favorable morphology, identifying micropores, suitable functional groups, notable surface area, pore volume, and elemental diversity. Batch experiments systematically investigated the influence of operational parameters, including contact time, initial MB concentration (5–35 mg/L), pH (2–10), and biosorbent dosage (2–10 g/L) on adsorption performance. The Langmuir isotherm model best represented the experimental data (R² values of 0.993 and 0.9725), indicating favorable adsorption (RL < 1) and maximum MB adsorption capacities of 0.822 and 0.330 mg/g for treated and untreated TGL, respectively. Statistical analysis (ANOVA) results further identified the most significant factors influencing MB biosorption. These findings highlight the potential of NaOH-treated TGL powder as an effective and eco-friendly solution for removing MB dye from industrial effluents, contributing to sustainable wastewater treatment and environmental protection.

Physiological and biomolecular interventions in the bio-decolorization of Methylene blue dye by Salvinia molesta D. Mitch

Methylene blue, a cationic dye as a pollutant is discharged from industrial effluent into aquatic bodies. The dye is biomagnified through the food chain and is detrimental to the sustainability of aquatic flora. Despite of number of physico-chemical techniques of dye removal, the use of aquatic flora for bio-adsorption is encouraged. Thus, we used Salvinia molesta D. Mitch in bio-reduction of methylene blue on concentrations of 0, 10, 20, and 30 mg L−1 through 5 days with biosorption kinetics. The dye removal was concentration-dependent, maximized at 2 days with 30 mg L−1 which altered the relative growth rate (44%) of plants. Biosorption recorded 71% capacity at optimum pH (8.0), 24 h reducing major bond energies of amide, hydroxyl groups, etc. Bioaccumulation of dye changed potassium content (446%) under maximum dye concentration modifying tissues for dye sequestration. Reactive oxygen species were altered on dye reduction by oxidase (33%) with redox homeostasis by enzymes. Plants altered the metabolism with over accumulation of polyamines (51%), abscisic acids (448%), and phosphoenolpyruvate carboxylase (83%) on dye reduction. Thus, this study is rationalized with a sustainable approach where aquatic ecosystems can be decontaminated from dye toxicity with the exercise of bioresources like Salvinia molesta D. Mitch as herein.

Alginate/clinoptilolite beads as a novel adsorbent for reducing the salinity of industrial wastewater: adsorption kinetics and isotherm study

ABSTRACT Treatment and desalination of unconventional water are considered important alternatives to combat water scarcity in Tunisia. This study demonstrates a viable approach to the increasing possibility of the salinity reduction of industrial effluent through adsorption. In this work, a novel alginate complex was developed for reducing the salinity of the industrial wastewater to be reinjected and reused again within the industrial process and even in agriculture. The Calcium alginate/clinoptilolite beads (Ca-Alg/Clino beads) were prepared using sodium alginate (2%) solution and calcium chloride (4%) solution as the crosslinking agent with clinoptilolite. Batch experiments were carried out to test the adsorption capacity of the synthetised Ca-Alg/Clino beads. It was found that the salinity reduction process depends strongly on the pH, the adsorbent mass, the interaction time, and the initial salt concentration. The highest reduction efficiency and salinity reduction were achieved at pH (6-7). Batch adsorption experiments indicated that Ca-Alg/Clino beads allow an excellent salinity reduction of up to 96.83% for a dosage adsorbent/water of 2 g/L and a salinity of 6 g/L at a contact time of 20 min. The maximum adsorption capacity (qmax) was 30.1 mg/g. The optimal adsorption pH was 7. The adsorption isotherms data follow well the Langmuir model. The separation factor, RL = 0.74, indicates that the adsorption process is favourable. The kinetics data favour the pseudo-second-order model. The fabricated beads can be reused 5 times without any weight loss. This material has excellent efficiency when applied to real environmental water.

High and temperature-stable electrostrain in lead-free environmentally friendly BiFeO3-BaTiO3 piezoelectric ceramics

Currently, environmental pollution and industrial effluents are depleting soil, water, and aquatic life and pose serious concerns to climate change. Environmentally friendly piezoelectric materials are considered potential agents for industrial applications, as they can generate clean energy by applying mechanical forces. High and temperature-insensitive piezoelectric strain is an ever-increasing demand in lead-free ceramics. In this work, a lead-free La-doped BiFeO3-BaTiO3 composition is designed at the crossover boundary of normal-relaxor ferroelectrics. The properties are optimized as a function of sintering temperature (Ts) from 960 to 1000 °C. An enhanced and thermally stable converse piezoelectric constant (d33∗) of 760 ± 23 pm/V over a wide range of 25–150 °C is achieved at an optimized TS of 980 °C. This high electrostrain response is mainly attributed to the low energy barrier for domain switching due to multiple-point crystal structure morphotropic phase boundary. Additionally, the high Curie temperature (TC) of 355 °C with excellent piezoelectric strain performance of our work are promising results for high-temperature piezoelectric actuators. The framework of chemical composition design and phase engineering of this work could inspire further development of lead-free ceramics for industrial applications.

Valorization of Strawberry Juice Production Wastewater: Possibilities for Polyphenols Recovery and Plant Biostimulant Production.

Fruit juice production is one of the most important branches of the food and beverage industry, considering both the market size and demand. It is also one of the largest generators of industrial wastewater, considering the large consumption of fresh water during fruit processing. Hence, the appropriate treatment strategies are of the utmost importance to minimize the environmental footprint of food industry effluents. This study aimed to investigate the valorization routes for strawberry juice production wastewater (SJPW), both in terms of nutrient recovery and a circular approach to its utilization as a medium for plant biostimulant production. The results show a low antioxidant capacity and low content of polyphenols in SJPW; however, promising results were obtained for the in vitro seed germination and tomato growth promotion when investigating a biostimulant based on Bacillus sp. BioSol021, which was cultivated using SJPW in a lab-scale bioreactor, with root and shoot length improvements of approximately 30% and 25%, respectively, compared to the control samples. The plant growth promotion (PGP) traits indicated the ability of IAA production, in a concentration of 8.55 ± 0.05 mg/L, and the enzymatic activity was evaluated as through the enzymatic activity index (EAI), achieving the following: 2.26 ± 0.04 for cellulolytic activity, 2.49 ± 0.08 for hemicellulolytic activity, 2.91 ± 0.16 for pectinolytic activity, and 1.05 ± 0.00 for proteolytic activity. This study opens a new chapter of possibilities for the development of techno-economically viable circular bioprocess solutions aimed at obtaining value-added microbial products for sustainable agriculture based on the valorization of food industry effluents thus contributing to more sustainable food production at both the agricultural and industrial levels.

GENOMIC INSTABILITY IN ONION (ALLIUM CEPA L.) IRRIGATED WITH INDUSTRIAL WASTEWATER: A CYTOGENETIC STUDY

Wastewater negatively affects the production of plants. The impact can vary depending on the wastewater content and the sensitivity of the plant type. The purpose of the current study was to look at the hazardous effects of wastewater from the steel and rubber industries on onions (Allium cepa). Twenty-four pots were filled with soil. Three replicates are used in this study to investigate the impact on Allium cepa. To evaluate the level of toxicity of the rubber and steel industries' waste waters, three concentrations of each wastewater and a control were selected. The concentrations for rubber industry effluent were chosen: 80% (S1), 90% (S2), and 100% (S3) and for steel industry 80% (R1), 90% (R2), and 100% (R3). Wastewater treatment inhibited root development when compared to control. Genotoxic research at different intensities showed chromosomal abnormalities. As the concentrations increased, the mitotic index fell and chromosomal abnormalities grew. Chromosome bridges, nuclear budding, sticky and coagulated anaphase and metaphase, and other chromosome abnormalities were seen. Overall, it was shown that the application of wastewater from the steel sector and wastewater from the rubber business had a detrimental effect on plant growth. However, when compared to rubber industry wastewater, steel sector wastewater has a higher level of toxicity. Compared to rubber sector waste water, steel industry wastewater has a higher concentration of heavy metals.

Effectiveness of constructed wetland technology-treated industrial wastewater on the spinach (Spinacia oleracea) health risks and biochar efficiency.

In peri-urban areas, use of industrial wastewater for irrigation is a common practice. Industrial wastewater contains cadmium, chromium, lead, nickel, and other elements that deteriorate food quality and affect human health. Biochar has been proven to remediate heavy metal contaminated soil by reducing their mobility and bioavailability. A pot experiment was conducted to evaluate the efficiency of different levels of biochar on spinach growth with low heavy metal concentration and to minimize associated health issues. The experiment lasted two months and the treatments: Control (tap water), untreated and treated industrial wastewater and both in combination with biochar (0.5% and 1%) were applied in completely randomized design. Findings suggested that treated industrial wastewater with 1% biochar resulted in maximum plant height, shoot weight, chlorophyll contents (SPAD value), photosynthetic and transpiration rate. Biochar significantly reduced heavy metal mobility in soil due to its porous structure, high pH, higher CEC, and variety of surface functional groups. The cumulative hazard index (HI), hazard quotient, cancer risk, and total cancer risk (TCR) were calculated using method provided by US-EPA for each metal. All treatments had HI values of < 1, however applying 1% biochar significantly reduced the HI values to 2.00E-01 and 2.88E-01 in adults and children, respectively. TCR for all treatments was < 1, while treated industrial wastewater and biochar (1%) has significantly reduced to 1.55E-02 and 1.91E-03 for adults and children, respectively. Thus, it was determined that irrigation with industrial effluents caused toxicity in vegetables, which had a negative impact on human health. Biochar effectively mitigated metal toxicity in both soil and spinach plants that resulted in reduced health/cancer risk.

Facile synthesis and characterization of magnetic iron oxide (Fe3O4)-loaded cationic amino-modified passion fruit shell nanocomposite and their application in removal of anionic Alizarin Red S dye from aqueous medium

A newly synthesized magnetic nanocomposite, iron oxide-loaded cationic amino-modified passion fruit shell (Fe3O4@CMPFS), was utilized as a sorbent to eliminate anionic Alizarin Red S (ARS) dye from the wastewater. The Fe3O4@CMPFS was characterized to confirm the properties by physicochemical methods such as VSM, XRD, pHPZC, BET, FTIR, and FE-SEM with EDX. Batch tests were conducted to study the adsorption process, focusing on factors like the solution pH (from 2.0 to 11), amount of Fe3O4@CMPFS (from 10 to 80 mg/30 mL), contact duration (from 0 to 240 min), agitation speed (from 0 to 400 rpm) and temperature (from 298 to 328 K). The optimal conditions for attaining a 92.3 % removal efficiency were found to be a pH of 2.0, 60 mg of Fe3O4@CMPFS, a contact time of 60 min, agitation at 250 rpm, and a temperature of 298 K. The Fe3O4@CMPFS was determined to have a pHPZC value of approximately 6.2. The kinetic data indicated that the adsorption of ARS onto Fe3O4@CMPFS followed the pseudo-second-order model (high R2 = 0.9919; low SSE = 1.5) and was governed by film and intraparticle diffusion mechanisms. Furthermore, the isotherm data fit well with the Langmuir model (high R2 = 0.9983; low χ2 = 12.69), suggesting monolayer adsorption behaviour. The maximal sorption uptake of ARS on the Fe3O4@CMPFS was determined to be 233.4 ± 3.174 mg/g at 298 K through the Langmuir model. The estimated ΔH° (18.3 kJ/mol) and ΔS° (82 J/mol K) indicate the endothermic and enhanced randomness at the adsorbent/solute interface. The negative ΔG° values (−6.2298 to −8.7283 kJ/mol at 298–328 K) confirm spontaneous sorption dominated by physisorption. The Fe3O4@CMPFS composite had good recyclability and was easy to separate from water, which maintained excellent adsorption performance after eight regeneration cycles. The superb adsorption efficiency and recycling performance of Fe3O4@CMPFS provide a prospect way to remove ARS dye from industrial effluents.

Robust regenerable metal-selenide-chitosan photocatalyst for the effective removal of Bromothymol Blue (BB) from wastewater

Water scarcity has been a crucial debate in recent years regarding the critical scenario of water pollution. The water body is continuously contaminated by organic effluents of textile industries, including pigmented dye pollutants. To tackle water bodies contamination, there is a need to develop an eco-friendly and efficient method for removing toxic dyes. Herein, ternary metal selenide nanocomposites of barium nickel selenide (NBSe-NPs) were synthesized by the solvothermal method supported by chitosan microsphere (NBSe-NPs-CM). Recovery of the catalyst was convenient by capping nanoparticles in the microsphere to maintain effective stability, biocompatibility, and well-designed surface coating. FTIR spectrum verified nanocomposite synthesis and chitosan microsphere (NBSe-CM) formation. SEM observations of nanocomposites and NBSe-CM indicated an average size of 13.78 nm and 253 μm, respectively. The presence of barium, nickel, and selenium elements in the NBS-NPs was verified by EDX analysis. The nanocomposites had a crystallite size of 15.73 nm. The photocatalyst exhibited a narrow bandgap of only 1.3 eV based on Tauc's plot. In addition, the synthesized microsphere demonstrated an efficient photocatalytic degradation (97 %) of Bromothymol Blue dye within 100 min under optimized operating conditions (pH of 6.0, dye concentration of 40 ppm, catalyst dosage of 0.25 g). The photocatalysis process followed the pseudo-first-order kinetics. The repeatability studies showed a slight decline in the catalyst's efficiency after four successive cycles. The DFT study shows that the NBSe-CM is energetically stable with more considerable negative binding energy, and the dye molecule interacts more strongly with the NBSe-CM surface. The findings highlight the exceptional characteristics of the newly designed ternary-metal-selenide-containing chitosan-microspheres for degrading dye contaminants from textile effluents.

First use of Chironomid Pupal Exuvial Technique in freshwater biomonitoring in Cameroon: Ecological aspect and morphological description of Chironomidae (Insecta: Diptera)

The biodiversity of urban streams is gradually degrading as a result of anthropogenic pollution. In this study, chironomid pupal exuviae were used as surrogates to assess urban streams and a lake in Douala Cameroon. We compared these assessments with samples collected from a suburban forest stream. Based on their highly adaptive capability, we predicted that chironomid communities would present high diversity and abundance in urban habitats. Chironomid pupal exuviae were collected using the chironomid pupal exuvial technique in 14 urban and 2 forest reference stations during dry and rainy seasons. Measurements of the environmental variables were done simultaneously. Physicochemical analysis revealed that all urban sites have had very poor ecological health status whereas forest site had good water quality as shown by the hierarchical cluster analysis. This ecological survey identified 8 species/morphotypes of chironomids all belonging to the subfamily Chironominae, tribe Chironomini. These are Chironomus holomelas(?), Chironomus sp.1, Chironomus sp.2, Chironomus sp.3, Chironomus (Lobochironomus) sp., Stenochironomus sp., Dicrotendipes sp. and Dicrotendipes pulsus. No midge pupal exuviae were recorded at the forest stations (S1 & S2) and the stations S6 and S7 located downstream industrial mill effluents. The species richness of the study sites was significantly very low as compare to other Afrotropical studies. Canonical redundancy analysis revealed that high values of water temperature, ammonium, nitrates and phosphates, and low oxygen concentration were significant predictors of the distribution and high abundance of Chironomidae. This survey highlighted the impacts of anthropogenic activities on chironomid diversity and distribution, with great decrease of their diversity due to industrial pollution.

Design of novel Z-scheme g-C3N4/TiO2/CuCo2O4 heterojunctions for efficient visible light-driven photocatalyic degradation of rhodamine B

One of the most important environmental challenges that needs to be resolved is the industrial discharge of synthetic dyes. Graphitic carbon nitride (g-C3N4), Titanium dioxide (TiO2) and flower-like copper oxide (CuO)/copper cobaltite (CuCo2O4) nanocomposites were synthesized in order to synthesis an effective visible light driven photocatalyst that could degrade Rhodamin B (Rh.B) dye under simulated solar light irradiation. The SEM and TEM results verifies that the flower-like CuO/CuCo2O4 (CCO) structure and g-C3N4/TiO2 (g-CN/TO) generated a smart hybrid structure with superior g-CN distribution. According to the photocatalytic studies, g- C3N4/TiO2/CuO/CuCo2O4 (g-CN/TO/CCO) shows good photodegradation of Rh.B dye (99.9%) in minmal times (1 h) in CCO: g-CN/TO (2:1) ratio by Z-Scheme mechanism. The enhanced visible light absorption and effective electron-hole pair separation provided by the synergistic dispersion of CuO/CuCo2O4 and g-C3N4 can be attributed to the improved photocatalytic performances. These novel insights into g-CN/TO/CCO based photocatalysts are useful for treating industrial effluent.

Development of free flowing granular hybrid functionalized clay sorbent filters for chromium removal from waste water

Chromium (VI) contamination in water resources at industrial sites poses significant environmental and health risks. Conventional sorbents often suffer from limitations such as clogging, back pressure, poor kinetics, and challenges in coupling with flow systems and regeneration. This study focuses on developing, characterizing, and applying free-flowing granular (FFG) amidoxime-functionalized montmorillonite (Mt) clay sorbents (AO-Mt-H-C) to enhance chromium (VI) removal from contaminated waste water. Batch adsorption experiments demonstrated that AO-Mt-H-C outperformed montmorillonite clay modified with quaternary ammonium alone (Mt-H-C), achieving a Cr (VI) removal efficiency of 50.6 mg g−1 compared to 44.3 mg g−1, due to the synergistic interactions of quaternary ammonium and amidoxime functionalities. To address the limitations of conventional sorbents, such as clogging and poor kinetics, an FFG filter column was developed and tested, showing effective Cr (VI) removal across various water sources with minimal interference in drinking and groundwater. In industrial wastewater with higher matrix loads, over 99 % removal efficiency was achieved with a 25 % increase in sorbent dosage. Desorption and reusability assessments confirmed the AO-Mt-H-C's effectiveness across three cycles. Mathematical modelling using Thomas and Yoon–Nelson equations supported the design of customized treatment systems. Scalability was demonstrated by treating 1.6 m3 of textile industrial effluents (100 mg L−1 Cr (VI)) with quantitative removal efficiency (>99.5 %). This study illustrates that the hybrid functionalization and free-flowing granulation of clay sorbent materials significantly enhance Cr (VI) removal, providing valuable insights for advanced water pollution mitigation and environmental sustainability.

Preliminary Study on The Characteristics of Effluent From A Cachoeiro de Itapemirim – ES and Analysis of Possible Biotechnological Treatments

Purpose: The objective of this research was to organize and evaluate physical-chemical parameters of the industrial dairy effluent and to propose viable alternative treatments using biotechnological methods, aiming not only to prepare the effluent for disposal but also to generate value-added products Theoretical framework: With the growth of the population, the food industry sector expands exponentially. Brazil ranks among the top five milk producers globally, with the dairy industry being a significant producer of effluent, generating between 1.1 m³ and 6.8 m³ of effluent per cubic meter of processed milk. Dairy wastewater carries a high pollutant load and requires treatment prior to discharge into water bodies. There is an increasing demand for converting waste into raw materials, prompting research into biotechnological treatments that not only prepare effluent for disposal but also yield products from such waste. Method/design/approach: The data on wastewater characteristics were provided by the dairy itself, and the physicochemical aspects of the effluents over 19 months were interpreted, establishing relationships among key parameters, as well as the ratios BOD/COD, BOD: N and COD: N. The survey of biotechnological treatments was conducted through bibliographic research on Google Scholar, Scielo, Web of Science, and Scopus databases. Results and conclusion: Through the analysis and correlations of the physicochemical characteristics of effluents from the Cachoeiro dairy, it is evident that this type of effluent is rich in low biodegradability organic matter, as the BOD5/COD ratio was less than 0.15 in over 79% of the samples, indicating that physical-chemical treatment is the most appropriate approach for this effluent. The linear correlation coefficient between BOD5 and COD was 0.6, suggesting a weak correlation that does not allow one parameter to be accurately predicted from the other. According to the literature, it is possible to derive biofuels, bioplastics, single cell protein, organic acids, polysaccharides, biosurfactants, and other products from dairy effluent, while also meeting environmental requirements Research implications: Evaluation of optimal treatments based on effluent characteristics and suggestion of alternative treatments aiming to utilize wastewater as a raw material for obtaining secondary products complementary to the industry's focus, in addition to compliance with current disposal regulations. Originality/value: Development of relationships to assist in evaluating effluent treatments and identification of treatments that can reuse this substantial volume of generated waste.

Ecological Implications of Seasonal Variations in Physicochemical Parameters and Phytoplankton Community in an Effluent‐Receiving Wetland in the Gulf of Guinea, Cameroon

ABSTRACTPhysicochemical parameters, chlorophyll a (Chl a) concentration, and phytoplankton community structure were assessed in the Wouri estuarine mangrove sector of the Douala Bassa Industrial Zone of Cameroon over two seasons. Three sets of water samples were collected from 10 sites for these analyses. Some physicochemical parameters were measured in situ using multiparameter equipment (HANNA 8289). The data were subjected to analyses of significant difference by an independent sample t‐test. Correlation and principal component analysis conducted between variables Temperature, salinity, total dissolved solids (TDS), resistivity, and turbidity showed a strong seasonal variation among sites. Mean Chl a concentration (3.7–48.29 µg/L for dry and 0.1–20.1 µg/L for rainy season) revealed that most sites were eutrophic, with the Euglenophycean index less than 1 in all the sites. Phytoplankton species richness exhibited seasonal and spatial variation, with a total of 74 taxa and 51 taxa for the dry and rainy seasons, respectively. The division Bacillariophyta was the most abundant, with 19 families and 24 species during the dry season and 17 families and 16 species during the rainy season. Other phytoplankton divisions present included Chlorophyta &gt; Cyanophyta &gt; Charophyta &gt; &gt; Myzozoa &gt; Euglenophyta in the dry season; the less diverse divisions in the rainy season were Rhodophyta &gt; Cryptophyta &gt; Xanthophyta &gt; Euglenophyta. High concentrations of nutrients and the presence of eutrophic species such as Microcystis aeruginosa suggest pollution and a need to monitor activities carried out along the water course with respect to the quantity and quality of industrial effluents discharged into the stream. The observed eutrophication explains the noxious odor across the city of Douala, especially during the dry season. The human health implications could be severe, with communities dependent on this contaminated stream for fish and other necessities a scenario that repeats itself in communities dependent on urban wetlands in industrial zones globally.

Adsorption of Carotenoids, Chloride, and Sulfate from Annatto Dye Agro-Industrial Effluent

&lt;p&gt;Natural dyes, such as annatto, are widely used in the food and pharmaceutical industries. However, the effluents from annatto dye production pose environmental challenges due to the presence of residual dye components, organic matter, and dissolved inorganic species (chloride and sulfate). This study, the first attempt in the literature to deal with real annatto dye effluent, aimed to evaluate the use of activated carbon for the removal of carotenoids (norbixin), chloride, and sulfate. A 2³ full-factorial design was employed to optimize the adsorption process parameters (temperature, pH, and adsorbent mass). The results showed that up to 90% of carotenoids and chloride could be removed under optimized conditions (low temperature and pH). Sulfate removal was more strongly influenced by the pH of the medium, with a maximum removal of 53%. The adsorption process was well-described by empirical models, though traditional isotherm models did not adequately represent the experimental data. Hypotheses that support isotherm models such as pore homogeneity, monolayer formation, constant internal diffusion were not satisfied. This study demonstrates the potential of activated carbon adsorption as a feasible method for treating food industry effluents containing high loads of carotenoids and inorganic salts.&lt;/p&gt;

Synergistic role of indium doping and g-C3N4 reinforcement in boosting the visible light-triggered rhodamine B and diclofenac sodium salt degradation over rare earth molybdate

Designing and fabricating cost-efficient and eco-friendly photocatalysts for removing organic pollutants from wastewater streams is a crucial research objective for effectively managing industrial effluents to tackle environmental sustainability issues. In this study, we prepared bare cerium molybdate (Ce2(MoO4)3, M1) and indium-doped cerium molybdate (In- Ce2(MoO4)3, M2) photocatalysts via a hydrothermal method. We then synthesized a nanocomposite of In- Ce2(MoO4)3 (M3) with the promising material graphitic carbon nitride (g-C3N4) using an ultrasonication approach. The synthesized photocatalysts were effectively applied to degrade the Rhodamine B dye and diclofenac sodium salt (a drug) from synthetic industrial wastewater through a photocatalysis approach. The impact of indium (In3+) doping on the bare (Ce2(MoO4)3 and the strong interaction between the (In-Ce2(MoO4)3 and g-C3N4 nanosheets were analyzed through physical and electrochemical techniques, including SEM, EDS, XRD, FTIR, UV–Vis spectroscopy, and EIS analysis. The comprehensive photocatalytic degradation of dye and the drug via first-order kinetic parameters under visible light irradiation for all the prepared catalyst samples was evaluated. The nanocomposite In-Ce2(MoO4)3/g-C3N4 exhibited excellent photocatalytic activity, degrading the maximum amount of RhB dye and drug (RhB:96 %, drug:87 %) in 90 min with a higher rate constant (k) compared to In-Ce2(MoO4)3 (RhB:69 %, drug:56 %) and Ce2(MoO4)3 (RhB:56 %, drug:38 %). Furthermore, the In-Ce2(MoO4)3/g-C3N4 samples produced a 7-fold and 3-fold increase in transient photogenerated current response compared to pristine Ce2(MoO4)3 and In-Ce2(MoO4)3 samples, respectively. These findings pave the way for synthesizing an economical, versatile, and efficient In-Ce2(MoO4)3/g-C3N4 photocatalyst to eliminate pollutants from industrial wastewater streams and boost environmental sustainability.

Mycosynthesis of TiO2 nanoparticles using Aspergillus penicillioides for toxic metal removal and photocatalytic applications

Globally, heavy metal pollution, especially lead and nickel, is becoming a problem and is of great concern due to its adverse effects. This study focuses on the eco-friendly biosynthesis of TiO2 nanoparticles using Aspergillus penicillioides metabolites as capping and reducing agents. The myco-synthesized TiO2 nanoparticles were characterized as oblate spherical and applied for photocatalytic removal of lead and nickel from industrial effluent. Optimal conditions for removal included lead and nickel concentrations of 60 μg/mL and 2 μg/mL, 10 μg/mL TiO2 nanoparticle concentration, a pH of 6, and sunlight irradiation. The kinetics and isotherm of adsorption were explained. Effective degradation of lead and nickel by using TiO2 nanoparticles was confirmed by atomic absorption spectroscopy. The nanoparticles demonstrated effective photocatalytic degradation of crystal violet dye achieved a high of 86.9% in 4h and 25% in 2 h, respectively, and showed promising biological activities, including antibacterial, antioxidant, and protein leakage properties. The hemolytic assay confirmed their ecological sustainability for bioremediation. The study highlights the effectiveness of new bio-based TiO2 nanoparticles arbitrated by Aspergillus penicillioides as effective bioremediation agents.

Solar-driven Pt free hydrogen production and successive degradation of sulfasalazine using CuO/ZnO binary nanocomposites: Reaction kinetics and determination of reaction parameters using response surface methodology

BackgroundApproaches for sustainable, green, and expensive catalyst-free hydrogen production have not been explored extensively. Moreover, during photocatalysis, a lot of material gets wasted due to a lack of proper optimization of the reaction parameters to remove the toxic industrial effluents. MethodsHere in this study, we present the green synthesis of CuO/ZnO nanocomposites from the ethanolic crude extract of Oxystelma esculentum. The synthesized photocomposites were systematically characterized by Fourier transform infrared spectroscopy, zeta potential, x-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and x-ray photoelectron spectroscopy. The performed analyses provided useful insights into identifying important functional groups, size, morphology, elemental composition, crystallinity, and defects in the synthesized photocomposites. Significant FindingsAfter characterization, the nanocomposites were evaluated for photocatalytic sulfasalazine (SSZ) degradation and hydrogen production. The response surface methodology (RSM) was employed to optimize SSZ's photocatalytic degradation. The optimized values of reaction parameters for the photocatalytic degradation of SSZ comprise pH = 4.06, SSZ dose = 47.75 mg/L, CuO/ZnO dose = 44.42 mg, and temperature = 23.60 °C. The rates observed in the hydrogen production (1136 µmolh-1g-1) were obtained without costly co-catalyst. The optimized values for hydrogen production include photocatalyst dosage = 50 mg, pH = 7, and time = 5 hours. These features signify the efficient separation of charge carriers between synthesized nanocomposites, resulting in exquisite activities.

Insights on Microplastic Contamination from Municipal and Textile Industry Effluents and Their Removal Using a Cellulose-Based Approach.

The rampant use of plastics, with the potential to degrade into insidious microplastics (MPs), poses a significant threat by contaminating aquatic environments. In the present study, we delved into the analysis of effluents from textile industries, a recognized major source of MPs contamination. Data were further discussed and compared with a municipal wastewater treatment plant (WWTP) effluent. All effluent samples were collected at the final stage of treatment in their respective WWTP. Laser diffraction spectroscopy was used to evaluate MP dimensions, while optical and fluorescence microscopies were used for morphology analysis and the identification of predominant plastic types, respectively. Electrophoresis was employed to unravel the prevalence of negative surface charge on these plastic microparticles. The analysis revealed that polyethylene terephthalate (PET) and polyamide were the dominant compounds in textile effluents, with PET being predominant in municipal WWTP effluents. Surprisingly, despite the municipal WWTP exhibiting higher efficiency in MP removal (ca. 71% compared to ca. 55% in textile industries), it contributed more to overall pollution. A novel bio-based flocculant, a cationic cellulose derivative derived from wood wastes, was developed as a proof-of-concept for MP flocculation. The novel derivatives were found to efficiently flocculate PET MPs, thus allowing their facile removal from aqueous media, and reducing the threat of MP contamination from effluents discharged from WWTPs.