Effect of Moringa oleifera Seeds Powder on Metallic Trace Elements Concentrations in a Wastewater Treatment Plant in Senegal

A wastewater treatment plant (WWTP) prototype coupled with Moringa oleifera seeds (MOSs) was developed to evaluate its effectiveness to reduce metallic trace elements (MTEs) in domestic wastewater. The WWTP is composed of a septic tank (F0) where wastewater is treated by biological processes under anaerobic conditions, followed by a bacterial filter (F1) where wastewater is filtered under aerobic conditions, followed by an infiltration well (F2), which provides additional filtration of wastewater before discharge into the soil. MTEs present in waters can bind with humic substances contained in colloid particles and then be eliminated by coagulation-flocculation with a cationic polyelectrolyte. MOSs contain positively charged cationic polymers that can neutralize the colloids contained in waters, which are negatively charged. Based on this observation, 300 mg·L-1 of MOS was added into F0, 50 mg·L-1 into F1, and 50 mg·L-1 into F2 mg·L-1. MOS activation in samples was performed by stirring rapidly for 1.5 min, followed by 5 min of gentle stirring and 3 h of settling. The data analysis shows that wastewater samples had significant concentrations of MTEs, particularly for Cu, Ni, Sr, and Ti, and sediment samples had high amounts of Cr, Cu, Ni, Sr, Ti, and V. The addition of MOS to F0, F1, and F2 samples resulted in reductions in MTE concentration of up to 36%, 71%, 71%, 29%, 93%, 81%, 13%, 52%, and 67% for Co, Cr, Cu, Ni, Pb, Se, Sr, Ti, and V, respectively. The quantified MTEs (As, Co, Cr, Cu, Ni, Pb, Se and V) in treated samples were reported to be lower than UN-EP standards for a safe reuse for irrigation and MOS proved to be as effective as chemical coagulants such as lime and ferric iron for the removal of MTEs contained in wastewater. These results highlight the potential of MOSs as natural coagulants for reducing MTE content in domestic wastewater. This study could be the first to evaluate the effectiveness of MOS in reducing 10 MTEs, including As, Co, Se, Sr, Ti, and V, which are currently understudied. It could also provide a better understanding of the origin of MTEs found in domestic wastewaters and how an effective treatment process can result in high-quality treated wastewaters that can be reused for irrigation without posing health or environmental risks. However, more research on MOSs is needed to determine the type and composition of the coagulant substance found in the seeds, as well as the many mechanisms involved in the decrease in MTEs by MOSs, which is currently understudied. A better understanding of MOS structure is required to determine the optimum alternative for ensuring the optimal effect of MOS paired with WWTP in removing MTEs from domestic wastewaters.

Kinetics and thermodynamics studies of nickel manganite nanoparticle as photocatalyst and fuel additive

In this study, nickel manganite (NiMn2O4) nanoparticles were prepared using a hydrothermal method and examined its potential as a photocatalyst for the Acid Green 25 (AG-25) dye degradation. The nanoparticles were subjected to structural analysis using X-ray diffraction (XRD) and morphological analysis using scanning electron microscopy (SEM). The study examined the kinetics and thermodynamics of degradation processes that are catalyzed by photocatalysis. To ascertain their effect on dye degradation, several parameters, such as catalyst dose, H2O2 concentration, and temperature, were investigated. With a temperature of 315 K in a pseudo-first-order kinetic reaction, a 0.3 M H2O2 concentration, 0.05 mg/mL catalyst dose, and a promising removal efficiency of 96 % was achieved by the NiMn2O4 NPs in 40 min. Thermodynamic analysis revealed the spontaneous and entropy-driven nature of catalytic degradation, progressing favorably at elevated temperatures. Additionally, the NiMn2O4 NPs were applied as a fuel additive to analyze its influence on combustion and the physical characteristics of the modified fuel. The modified fuel demonstrated exceptional catalytic efficiency, emphasizing the potential of the NiMn2O4 NPs as an effective additive.

Paracetamol and amoxicillin adsorptive removal from aqueous solution using phosphoric acid activated-carbon

Charcoal-based materials have attracted much attention for the removal of pharmaceutical agents. The charcoal-based carbon materials have green synthetic routes, high surface area, numerous active site with active functional groups available for physico-chemical interactions with adsorbate for surface-adsorptive removal of toxins. In this study, acid treated activated carbon was developed from the peach seeds using thermal pyrolysis approach. Phosphoric acid activated carbon (PAC) was further modified by HNO3 and employed as an adsorbent for the removal of amoxicillin and paracetamol and process variables were optimized for enhanced removal of amoxicillin and paracetamol. The adsorption of pharmaceutical agents was significantly affected by temperature, pH and reaction time. The amoxicillin and paracetamol sorption process onto PCA followed a pseudo second order kinetics and Langmuir isotherm model with a maximum removal capacity of 51.8 mg/g and 51.1 mg/g, respectively. The results revealed that acid activated carbon has promising efficiency for the removal of amoxicillin and paracetamol from aqueous medium and peach seeds derived PCA could be employed for the removal of these pharmaceutical agents from effluents and PAC is also extendable for the removal of other drugs from pharmaceutical wastewater streams.

Kinetic studies and conditions optimizations for the removal of direct red 80 dye from wastewater using cotton calyx and iron oxide composite

This study focusses on the adsorption efficiency of cotton pod (Gossypium arboreum) for biosorption of direct red (DR) 80 dye. The effect of dye concentration, pH, shaking time, adsorbent dose and temperature was considered to evaluate the adsorption efficiency of the cheapest raw material on the removal of dye. Various concentrations (10–50 ppm) were examined and maximum percentage removal of the adsorbent was obtained at pH 1 with adsorbent dose of 0.9 g and shaking time of 60 min. To enhance the adsorption efficiency of the adsorbent, the cotton calyx was treated with FeSO4.7H2O and investigated the removal of the raw adsorbent and the composite. It was examined that the removal efficiency of the composite is more than that of raw adsorbent. The composite was more efficient as dye removal reached up to 97%. FTIR of the composite shows an additional peak at 650 cm−1 for presence of Fe-O group and confirmation of composite formation. SEM micrograph showed that the particles in composite are more packed compared to the raw adsorbent. Mathematical models were applied and kinetic studies also have been done to provide better results regarding to the experimental data. It is concluded that the prepared adsorbent could be used as a tool for the removal of toxic pollutants from textile wastewater.

Extraction of silica from fly-ash and fabrication of silica-clay composite for dye removal and kinetic studies

A facile and green approach to extract silica from the coal fly-ash waste is extremely critical for environmental sustainability and economically suitable. In this study, we have used acid-alkali coupled approach to improvised the proficiency of the extraction process. The sodium hydroxide (NaOH) soaking results the formation of the sodium silicate (Na2SiO3) solution then pure silica was obtained by heating at high temperature; this coupled route-way results better yield of silica (SiO2) which is ∼ 40 g. The efficiency of pure silica is not enough to remove toxic effluents from the aqueous media. A highly versatile approach of composite formation was adopted to fabricate silica-clay composite using kaolinite-clay and extracted silica. Both materials, extracted silica and its silica-clay composite were analyzed using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) method, X-ray diffraction technique (XRD) and Fourier transform infra-red spectroscopy (FTIR). The silica-clay composite showed plate-tubular like morphology with enormous binding sites available for the sorption pollutants like organic dyes. It has shown excellent sorption of methylene blue (MB) efficiency of 131.5 mg/g, while silica furnished the sorption of 70.5 mg/g. Results revealed that the synthesized material could probably have better potential for dye removal from industrial effluents.

Eco-benign preparation of biosorbent using Momordica Charantia for the efficient removal of Cr(VI) ions from wastewater

Environmental pollution is the major issue of 21st century. The toxic industrial effluents are crucially damaging aquatic environment, in the form of heavy metals, dyes and acids. The heavy metals are toxic, carcinogenic, non-degradable and therefore must be removed to save natural environment and human health. Batch sorption efficiency of Momordica Charantia L. stem and root (MCS and MCR) was studied for Cr(VI) metal ions removal under controlled adsorption parameters. The adsorbed and residual concentration of Cr(VI) was determined by atomic absorption spectrophotometer (AAS). The adsorbent surface morphology was determined by FTIR, BET, SEM and elemental analysis by EDX. The Freundlich and Langmuir equilibrium isotherm and pseudo 1st and 2nd order kinetic models were studied to understand bio-sorption mechanism. The Freundlich isotherm and pseudo 2nd order kinetic was best fitted model for MCS and MCR bio-sorption process. The maximum Langmuir adsorption capacity (q max) was 312.50 and 400 (mg/g) for MCS and MCR respectively. The trend of removal efficiency (%) and metal uptake (q e) was in order as MCS > MCR. All data was statistically analyzed using mean values ± standard deviation (SD). In conclusion, MCS and MCR are suggested as excellent sorbents for the elimination of numerous contaminants from the wastewater.

Removal of Cr(III) from Aqueous Solution Using Labeo rohita Chitosan-Based Composite

This study focusses on the synthesis of chitosan-cellulose composite membrane derived from Labeo rohita fish scales (FS) for the removal of Cr(III) from aqueous solution, while chromium is a serious threat to groundwater. Waste FS are valorized to chitosan by demineralization, deproteination, and deacetylation successively. Cellulose was extracted from sugarcane bagasse using acidic hydrolysis. Chitosan-based cellulose composite porous membrane was fabricated by evaporating solvent from polymer solution in petri dish. The impact of pH, contact time, and absorbent dosage on the removal of Cr(III) from an aqueous solution was investigated. Atomic absorption spectrophotometer was used to check the Cr(III). Results showed that chitosan comprising 85% degree of deacetylation was achieved by alkali treatment, while yield was 22%. FTIR analysis confirmed the chitosan and chitosan-cellulose-based composite membrane. Morphology studies showed that the cellulose was strongly staggered and due to the chitosan, the surface of cellulose became rougher, which is good to enhance the adsorption capacity. The maximum removal 57% of Cr(III) from aqueous solution was observed at pH 6 at 60 min and 50 mg dosage of adsorbent. The minimum removal (47%) of Cr (III) was found at pH 2. These results confer that Labeo rohita-based chitosan-cellulose composite membrane has great potential for the removal of metals from industrial effluents.

Ionizing radiation based advanced oxidation process for reactive orange 122 dye degradation and kinetics studies

In the current study, the degradation of reactive orange 122 (RO 122) dye was carried out under UV and gamma irradiation in presence of H2O2. The effect of variables such as UV exposure time, gamma-ray absorbed dose, initial concentration of dye and oxidant dose were investigated. The removal of 64.10, 58.84 and 55.46 (%) was observed for 50, 100 and 150 (mg/L) dye concentrations, respectively using UV radiation time of 150 (min). The degradation was enhanced to 80.39, 69.95 and 67.01 (%) when UV radiation was employed in the presence of H2O2 (0.5 mL/L) for above concentrations respectively. The degradation was further improved to 97, 92.54 and 81.32 (%) using 5 kGy absorbed dose along with H2O2 (0.5 mL/L). The reduction in chemical oxygen demand (COD) was 77, 64 and 57 (%) using UV/H2O2 (0.5 mL/L), while 63, 56 and 53 (%) in case of gamma/H2O2 for aforementioned concentrations. The removal efficiency (G-value), dose constants (k), dose indispensable for 50, 90 and 99 (%) degradation (D 0.5, D 0.90, and D 0.99) after the treatment with gamma radiation were determined. The G-value was noted as 0.46–0.0711 for 50–150 mg/L dye concentration for gamma irradiated samples which improved to 0.57–0.1204 for above mentioned concentrations in presence of H2O2. The FTIR analysis showed that all the peaks were disappeared using gamma/H2O2 at 5 kGy absorbed dose except a minor peak of −CO stretching. The degradation mechanism of dye followed pseudo-first-order kinetics. A significant decrease in peak area was observed by the HPLC analysis after treating the dye samples with gamma/H2O2 (0.5 mL/L) at absorbed dose of 5 kGy which has proven the process efficiency for dye degradation.

Catalytic degradation of MO and MB dyes under solar and UV light irradiation using ZnO fabricated using Syzygium Cumini leaf extract

Zinc oxide nanoparticles (ZnO NPs) were fabricated using Syzygium cumini leave extract as a reducing and capping agent. The ZnO NPs were characterized using various techniques including scanning electron microscopy, UV-Visible and energy dispersive X-ray (EDX) techniques. The ZnO nanoparticles size was in 0.2–1 µm range and spherical in shape. Photocatalytic efficiency of ZnO NPs for the removal of MB (methylene blue) and MO (methyl orange) was investigated under solar and UV light expire. Photocatalytic efficiency of ZnO NPs was promising, which was found to be high under UV irradiation versus solar light. The ZnO NPs was confirmed as appropriate photocatalytic agent with significant potential for the removal of dye from wastewater.

Kinetics of acid blue 40 dye degradation under solar light in the presence of CuO nanoparticles synthesized using Citrullus lanatus seeds extract

In view of eco-benign nature of green synthesis, in the present investigation, the CuO NPs are prepared using Citrullus lanatus seeds extract and photocatalytic degradation efficiency for Acid Blue 40 (AB-40) was evaluated. The CuO NPs were characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy), EDX (energy dispersive X-ray), and FT-IR (Fourier transform infrared) techniques. The synthesized CuO NPs was in face centered monoclinic crystalline form with particle size in 40–60 nm range. The photocatalytic degradation potential of CuO NPs was assessed for acid blue 40 (AB-40) dye degradation and catalyst dose, concentration of dye, radiation exposure time and pH are considered for dye removal. The CuO NPs exhibited auspicious efficiency, an 84.89% dye removal was attained at optimal conditions and dye degradation followed BMG (Behnajady–Modirshahla–Ghanbery) kinetics model. Results revealed CuO NPs synthesized using C. lanatus seeds extract is photoactive catalyst and green route can be employed for CuO NPs fabrication for photocatalytic applications.

Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

Kinetics of methylene blue dye adsorptive removal using halloysite nanocomposite hydrogels

In the present work, halloysite nano-clay (HNTs) based hydrogel was fabricated and their efficiency for the removal of methylene blue dye was studied. The hydrogel films were prepared with varying amount of halloysite nano-clay via facile solution casting method. Effect of halloysite clay on adsorption performance of composite was investigated. The hydrophobic thermoplastic synthetic polymer, polylactic acid (PLA) was blended with hydrophilic polymer polyvinyl alcohol (PVA) and HNTs to synthesize hydrogels. Swelling behavior and antimicrobial efficiency was also evaluated. The halloysite incorporating films showed excellent antibacterial activity. Swelling capacity of hydrogel with increased halloysite content was reduced due to increased crosslinking among polymer chains. Halloysite incorporated hydrogel exhibited higher adsorption ability as compared to film comprising of only PVA and PLA and dye removal followed pseudo first order kinetics. Film with 0.03 g HNTs rapidly attained adsorption-desorption equilibria and removed the dye completely within 30 min. Results confirmed that synthesized film could be potentially used for the removal of cationic dye and fabricated hydrogel film have promising potential for wastewater treatment since a higher adsorption capacity was observed for halloysite nano-clay incorporated hydrogel.

Highly photosensitized Mg4 Si6O15 (OH)2·6H2O@guar gum nanofibers for the removal of methylene blue under solar light irradiation

In the present investigation, photosensitized nanofibers (NFs) based on guar gum (GG)/poly(vinyl alcohol) (PVA)/Mg4Si6O15(OH)2·6H2O (SP) (modified by 1, 4-diamminobutane [DAB]) was fabricated by electrospinning approach and same was used for the degradation of dye under solar light irradiation. For electrospinning of NFs, the acceleration voltage, nozzle flow rate and collector distance levels of 19,000 KV, 0.5 mL/h and 3 cm were optimum conditions along with 7% (w/v) blend of GG/PVA (1.4:5.6 wt/wt) and 0.01 g modified Mg4Si6O15(OH)2·6H2O. The exfoliation, intercalation and clay organophilization in GG/PVA/Mg4Si6O15(OH)2·6H2O (GG/PVA/SP) NFs were examined by FTIR analysis. The photocatalytic activity (PCA) of NF was studied under the solar light irradiation for methylene blue (MB) dye degradation. The photosensitized GG/PVA/SP2 (G3) showed promising PCA under visible light and G3 furnished higher degradation of MB dye (99.1%) within 10 min of irradiation. Results revealed that GG/PVA/SP based NFs are highly active under solar light, which can be applied for the treatment of wastewater.

Greener approach to substitute chemical reduction clearing process for fabric dyed with Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL using indigenous resources

Fabric dyed with disperse dyes followed a reduction clearing process (RCP)/chemical clearing process (CCP) to remove the unfixed dye from the fabric. In the clearing process, unfixed dyes and chemicals are discharged into streams. To combat this issue, an environment friendly approaches is explored that is a biological clearing using indigenous fungal strains of white-rot fungi (Pleurotus ostreatus and Ganoderma lucidum). In this context, fabrics dyed with three disperse dyes (Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL) were considered. The fabric cleared with biological clearing process improved the quality of fabric versus chemically cleared fabric and among the tested strains, G. lucidum showed higher efficiency for color strength improvement. However, no significant difference in tensile and tear strength of all fabric samples was observed. The quality of effluents in clearing reduction process for three dyes was assessed and it was observed that water quality parameters including chemical oxygen demand (COD), total organic carbon (TOC), biological oxygen demand (BOD), total suspended solids (TSS), pH, dissolved oxygen (DO) and total dissolved solids (TDS) improved significantly and results revealed that the biological clearing approach can substitute chemical reduction clearing process for fabric dyed with dyes, which is greener and eco-friendly versus conventional processes to avoid unfixed dyes discharge in to water bodies.

Synthesis of Cu-doped MgO and its enhanced photocatalytic activity for the solar-driven degradation of disperse red F3BS with condition optimization

In the present study, Cu (2–12%) doped MgO was synthesized and characterized by SEM, XRD, EDX, and FTIR spectroscopy. The Cu concentration significantly affected the band gap and particle size, which ranged from 4.63 to 3.78 eV and from 27.2 to 79 nm, respectively. In addition, the photocatalytic activity (PCA) of Cu-doped MgO was monitored by the photocatalytic destruction of disperse red F3BS coralene dye, and four reaction variables such as dye concentration, catalyst dose, hydrogen peroxide concentration, and irradiation time, respectively, were optimized by response surface methodology (RSM). Dye degradation was significantly affected by these process variables, and a degradation rate of up to 93% was achieved under optimized conditions. The wastewater samples were also treated under optimized conditions and water quality variables, i.e., chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were significantly improved after treatment. Cu-doped MgO exhibited excellent PCA under the solar-light exposure for the degradation of disperse red F3BS dye, which can be employed for the treatment of dye-containing effluents.

Synthesis and characterization of magnetically separable La1−x Bi x Cr1−y Fe y O3 and photocatalytic activity evaluation under visible light

A series of Bi and Fe doped La1−x Bi x Cr1−y Fe y O3 (x = 0.00–0.10 and y = 0.02–0.12) perovskites were fabricated through a facile microemulsion method and were characterized by XRD, DC electrical-resistivity, dielectric, VSM, and UV–Visible measurements. Orthorhombic phase of synthesized substituted chromite nanocrystallite was confirmed by powdered XRD analysis with crystallite size in 47.8–32.9 nm range. DC electrical resistivity was observed to increase from 1.70–39.99 × 108 Ω-cm. Dielectric parameters analyzed in frequency range of 20 kHz–20 MHz were decreased, while magnetic parameters were observed to increase with the increase in dopant (Bi+3 and Fe+3) concentration. Whereas coercivity values was low (narrow hysteresis loop), which indicate the soft ferromagnetic of the prepared material materials which are quite useful to employ in storage devices and electronics. Moreover, La1−x Bi x Cr1−y Fe y O3 degraded 90.80% Rhodamine B dye under visible light irradiation within 55 min. The increase in electrical resistivity, while decrease in dielectric parameters was also observed with increase in dopant concentration, ferromagnetic nature and excellent photocatalytic properties make this material suitable for high frequency energy devices, microwave appliances as well as an excellent magnetically separable photocatalyst for the purification of contaminated wastewater.