Bioremoval of heavy metals from aqueous solution using dead biomass of indigenous fungi derived from fertilizer industry effluents: isotherm models evaluation and batch optimization.

The present work investigated the utilization of dead biomass of the highly multi-heavy metals tolerant indigenous fungal strain NRCA8 isolated from the mycobiome of fertilizer industry effluents that containing multiple heavy metal ions at high levels to remove Pb2+, Ni2+, Zn2+, and Mn2+ as multiple solutes from multi-metals aqueous solutions for the first time. Based on morphotype, lipotype and genotype characteristics, NRCA8 was identified as Cladosporium sp. NRCA8. The optimal conditions for the bioremoval procedure in the batch system were pH 5.5 for maximum removal (91.30%, 43.25%, and 41.50%) of Pb2+, Zn2+ and Mn2+ but pH 6.0 supported the maximum bioremoval and uptake of Ni2+ (51.60% and 2.42 mg/g) by NRCA8 dead biomass from the multi-metals aqueous solution, respectively. The 30 min run time supported the highest removal efficiency and uptake capacity of all heavy metals under study. Moreover, the equilibrium between the sorbent NRCA8 fungal biomass and sorbates Ni2+, Pb2+ and Zn2+ was attained after increasing the dead biomass dose to 5.0 g/L. Dead NRCA8 biomass was described by scanning electron microscopy, energy-dispersive X-ray spectroscopy and Fourier transform infrared spectrometer before and after biosorption of Pb2+, Ni2+, Zn2+ and Mn2+ under multiple metals system. The Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich isotherms were applied to characterize the adsorption equilibrium between Pb2+, Ni2+, Mn2+ and Zn2+ and the adsorbent NRCA8. By comparing the obtained coefficient of regression (R2) by Freundlich (0.997, 0.723, 0.999, and 0.917), Langmiur (0.974, 0.999, 0.974, and 0.911) and Dubinin-Radushkevich (0.9995, 0.756, 0.9996 and 0.900) isotherms values for Pb2+, Zn2+, Ni2+ and Mn2+ adsorption, respectively, it was found that the isotherms are proper in their own merits in characterization the possible of NRCA8 for removal of Pb2+, Zn2+, Ni2+ and Mn2+. DKR isotherm is the best for Pb2+ and Ni2+ (0.9995 and 0.9996) while Langmiur isotherm giving a good fit to the Zn2+ sorption (0.9990) as well as Freundlich isotherm giving a good fit to the Mn2+ sorption (0.9170). The efficiencies of Cladosporium sp. NRCA8 dead biomass for bioremoval of heavy metals from real wastewater under the optimized conditions were Pb2+, Ag+, Mn2+, Zn2+ and Al3+ ˃ Ni2+ ˃ Cr6+ ˃ Co2+ ˃ Fe3+ ˃ Cu2+ ˃ Cd2+. Dead NRCA8 biomass showed efficient ability to adsorb and reduce harmful components in the industrial effluents to a level acceptable for discharge into the environment.

Innovative green/non-toxic Bi2S3@g-C3N4 nanosheets for dark antimicrobial activity and photocatalytic depollution: Turnover assessment.

Herein, green and non-toxic bismuth sulphide@graphitic carbon nitride (Bi2S3@g-C3N4) nanosheets (NCs) were firstly synthesized by ultrasonicated-assisted method and characterized with different tool. Bi2S3@g-C3N4 NCs antimicrobial activity tested against three types of microbes. As well the heterostructured Bi2S3@g-C3N4 NCs was investigated for removing dye and hexavalent chromium under visible light and showed high efficiency of photocatalytic oxidation/reduction higher than g-C3N4 alone, attributing to lower recombination photogenerated electron-hole pairs. Bi2S3@g-C3N4 NCs showed high antimicrobial efficiencies against Staphylococcus aureus (S. aureus) as a Gram positive bacterium, Escherichia coli (E. Coli)as a Gram negative bacterium and Candida albicans (C. albicans) and that the disinfection rates are 99.97%, 99.98% and 99.92%, respectively. The core mechanism is that the bacterial membrane could be destroyed by reactive oxygen species. The Bi2S3@g-C3N4 NCs is promising for environmental disinfection including water and public facilities disinfection and solar photocatalytic depollution. Turnover number (TON) and Turnover frequency (TOF) are used as concise assessment indicator for photocatalytic efficiency.

Elucidating the Environmental and Health Risks of Trace Element Pollution in Red Sea Fish from Nuweiba City, Aqaba Gulf, Egypt.

Trace element bioaccumulation in marine organisms is a rising international issue due to possible health concerns for humans. Thirteen trace elements were analyzed in the sediment, water, and muscular tissue of Red Sea fish. Additionally, the average daily intake (EDI), the cancer risk (CR), the hazard index (HI), and the target hazard quotient (THQ) of those elements have been taken into consideration when evaluating any possible health concerns related to their consumption. All species presented quantifiable values in muscle for all the analyzed elements (arsenic (As), lead (Pb), copper (Cu), aluminum (Al), boron (B), iron (Fe), barium (Ba), manganese (Mn), nickel (Ni), cadmium (Cd), chromium (Cr), zinc (Zn), and mercury (Hg), except for Cd and Hg, being Fe and Zn the most accumulated elements in all species. Conversely, in water samples, most elements were undeleted except for aluminum, boron, iron, and zinc. All Red Sea fish, however, had concentrations of Zn, Ni, Fe, Cu, and Mn below the upper limit allowed, although most species had higher levels of As, Cr, and Pb (0.48 ± 0.83-5.10 ± 0.79, 1.97 ± 0.46-5.25 ± 0.67 and 2.12 ± 1.01-6.83 ± 0.93 µg/g, respectively).The studied Red Sea fish showed contamination degrees (CD) of Mn, Cu, Fe, Ni, Zn, and Pb were ≤ 1, indicating minimal contamination, with As and Cr showing higher contamination degrees. However, the pollution index values (MPI-elements) can be represented according to ascending order: Lethrinus ramak < Cephalopholis hemistiktos < Pagellus affinis < Trachurus japonicus < Cheilinus lunulatus < Siganus luridus < Parupeneus forsskali < Caesio suevica. The study found that edible tissues are safe for human consumption, with HI values for children and adults less than ten, indicating negligible non-cancer hazards. However, fish consumption presents health risks due to chromium, lead, and arsenic, with THQ values several times greater than 1, and CR-Ni, CR-Cr, and CR-As values exceeding the acceptable 10-4 value in all studied species. This study provides critical insights into trace element contamination in marine fish species, highlighting the need for ongoing monitoring and proactive measures to ensure safe marine fish consumption in the Aqaba Gulf.

Multimetal bioremediation from aqueous solution using dead biomass of Mucor sp. NRCC6 derived from detergent manufacturing effluent.

Among ten metal-tolerant fungal isolates obtained from the microbiomes of detergent industry effluent, Mucor sp. NRCC6 showed the highest tolerance and an adaptive behavior toward the heavy metals Ni2+, Pb2+, Mn2+, and Zn2+. It gave the highest growth rates 0.790 ± 0.59, 0.832 ± 0.32, 0.774 ± 0.40, and 0.741 ± 1.06 mm/h along with the lowest growth inhibition 9.19, 4.37, 11.04, and 14.83% in the presence of Pb2+, Zn2+, Ni2+, and Mn2+, respectively, at a concentration of 5.0 g/L. Then, Mucor sp. NRCC6 was selected as a biotrap for the removal of these heavy metals. The optimized operating conditions were detected to be pH 6.0 for Pb2+, Zn2+, and Mn2+ and pH 5.5 for Ni2+ at 30 °C; agitation speed 150 rpm; contact time 30 min for Mn2+ and Ni2+, 30-60 min for Pb2+, and 90-180 min for Zn2+; NRCC6 biomass dosage 5.0 g/L for Ni2+ and Pb2+ and 10.0 g/L for Mn2+ and Zn2+; and initial concentration 12 mg/L of each ion in the multimetal aqueous solutions. Under these optimized conditions, the adsorption capacity for Pb2+, Ni2+, Mn2+, and Zn2+ reached 98.75, 59.25, 58.33, and 50.83%. The Langmuir isotherm was the best for describing the adsorption of Zn2+ (0.970) and Mn2+ (0.977). The Freundlich isotherm significantly giving a good fit to the adsorption of Pb2+ (0.998) while the adsorption of Ni2+ onto NRCC6 biomass can follow DKR (0.998). Furthermore, the current study revealed that Mucor sp. NRCC6 fungus is a new efficient and eco-friendly method that revealed a maximum removal of 100% for Pb2+ and Zn2+ as well as 97.39, 88.70, 78.95, 74.0, 70.22, 68.57, and 60.0% for Ni2+, Mn2+, Cd2+, Cu2+, Fe3+, As2+, and Cr6+ from the industrial wastewater, respectively.

Nanocarbon hybrid for simultaneous removal of arsenic, iron and manganese ions from aqueous solutions.

Heavy metal contamination is a severe problem with serious ecological and human health effects due to its toxic effect and tendency to accumulate throughout the food chain. Batch experiments were conducted to investigate the simultaneous removal of arsenic, iron and manganese ions from aqueous solutions using Nanocarbon hybrid (NCH). Nanocarbon hybrid (NCH) of carbon xerogel decorated with 1wt% multi-walled carbon nanotubes was prepared by carbonization at 850 °C for 2 h. The TEM, SEM, EDX, FTIR, and N2 adsorption-desorption measurements were used to characterize the prepared NCH. NCH is enriched with surface oxygen functional groups and micropores as well as it have total surface area of 162 m2/g and total pore volume of 0.129 cm3/g. The adsorption of metal ions onto NCH, which confirmed by EDX, happened quickly, with 30%, 97%, and 41% of As, Fe, and Mn adsorbed in less than 10 min, however the equilibrium time was achieved in less than 30 min. The maximum adsorption capacities for As, Fe, and Mn ions onto NCH were 20, 48, and 21 mg/g, respectively. The experimental adsorption results of the three metal ions showed linearly fitting with Freundlich isotherms. In addition, the computed adsorption energies for Fe, Mn, and As ions were 4.08, 1.95, and 2.42 kJ/mol, indicating physical adsorption. NCH are easily regenerated and reusable sorbent owing to the adsorption-desorption studies. Conclusively, NCH is promising material for removing mixture of metal ions from aqueous media.

Low temperature-calcined TiO2 for visible light assisted decontamination of 4-nitrophenol and hexavalent chromium from wastewater.

In the present study, alkaline hydrothermally treated titania nanoparticles (TiO2-HT) are prepared and followed by calcination at different low temperatures to improve TiO2 activity under visible light. The prepared photocatalysts (PCs) are characterized by different tools. TiO2-HT is scrutinized for decontamination of para-nitrophenol (PNP) and hexavalent chromium ions (Cr6+ ions) under simulated sunlight. TiO2-HT-300 and TiO2-HT-400 PCs have nanosized particle with large surface area of 148 and 116.26 m2/g, respectively. Additionally, XRD and FTIR proved formation of nanocrystalline anatase TiO2. The different calcined TiO2-HT materials show lower adsorption capacity for PNP and Cr6+ ions. TiO2-HT-300 and HT-TiO2-400 PCs have higher reduction rate of PNP than that of uncalcined temperature titania (HT-TiO2-U) powder. Complete conversion of PNP is achieved at natural pH after 180 min over TiO2-HT-300. As well, TiO2-HT-300 exhibits a superior photocatalytic removal of Cr6+ ions. The enhanced photocatalytic efficacy is ascribed to the synergism between higher surface area and particle size (quantum effect) of TiO2-HT-300. As results, HO· radicals are the main key active species for the photocatalytic degradation of PNP over TiO2- HT-300 PC but contribution of O2- and h+ holes is minor. The used method for preparation of TiO2-HT-300 reduces the cost preparation as well as environmental impact reduction. Finally, low temperature-calcined TiO2 is promising visible light active and an efficient photocatalyst with lower environmental impact for detoxification of PNP and Cr6+ ions from water.