Removal of lead ions from industrial wastewater: A review of Removal methods

Background and aims: The removing of (potential) toxic heavy metal ions from sewage, especially in industrial and mining waste effluents, has been widely studied in recent years. The aim of present study was to investigate the various methods for lead removal of lead ions from industrial wastewater. Methods: This study was a review research. Data were collected through different databases in various articles. The various methods for lead removal from industrial wastewater were compared to each other. Results: The present study showed the various methods for lead removal from industrial wastewater including chemical precipitation, electrochemical reduction, ion exchange, reverse osmosis, membrane separation, and adsorption. Technical applicability, plant simplicity and cost-effectiveness are the key factors that play major roles in the selection of the most suitable treatment system for inorganic effluents. Conclusions: Adsorption is proposed as an economical and effective method for the retention of lead ions from aqueous industrial wastes because it is simple, effective and economic in removal of heavy metals from aqueous solution

Nitrate removal from aqueous solution by almond shells activated with magnetic nanoparticles

Magnetic activated carbons from almond shells were prepared, characterized, and used to remove nitrate from aqueous environments. The magnetic carbon was prepared by mixing of activated carbon in aqueous suspensions with an aqueous Fe3+/Fe2+ solution followed by treatment with sodium hydroxide. The morphologies and surface chemistries of magnetic activated carbon were studied by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray microanalysis, pHpzc, and Brunauer–Emmett–Teller (BET) analyses. The BET area of magnetic activated carbon was 105.480 m2 /g. The effects of adsorbent dosage, the pH of the solution, initial nitrate ion concentration, and contact time on the removal process were investigated. The amount of remaining nitrate ion was measured by spectrophotometer UV–Vis after filtration. At optimum pH of 4 and equilibrium time of 20 min, adsorption efficiency increased with both increasing of absorbent concentration to 1 g/L and reduction of initial concentration of nitrate ions (76.29%). The equilibrium adsorption was best described by the Langmuir isotherm model (R2 = 0.924). The almond shell activated with magnetic nanoparticles has a good ability to remove nitrate ions from aqueous solutions. Therefore, the use of this relatively easy and simple technology is an effective step in removing nitrate from water

Removal of acid bleu 113 by UV/H2O2/Fe3O4 process: Optimization of treatment conditions using experimental design

Background and aims: Colored wastewaters are highly toxic for animals, human and habitat areas and cause several diseases in humans such as allergy, cancer and mutation. This study was aimed to remove of acid blue 113 color with application of UV/H2O2 with nano-catalyst of Fe3O4. Optimization of the process was investigated using experiment design methodology. Methods: In this experimental study, in order to study the effective parameters such as initial concentration of acid blue 113 (AB 113), pH, contact time, amounts of hydrogen peroxide and nano-catalyst Fe3O4 in removal of acid blue 113 and finding optimal conditions was investigated using of response surface methodology. Data were analyzed using design experiment software. Results: Optimum conditions of removal including initial concentration of AB113 dye 62.3 mg/L, pH 3.83, contact time 29.5 minutes, the amount of hydrogen peroxide 31.53 mmol/L and concentration of Fe3O4 1.81 g/L were obtained for maximum removal efficiency of 95.51%. The removal efficiency by increasing H2O2, contact time and catalyst concentration increased and with increasing of initial dye concentration and pH was decreased. Conclusion: The results showed that the removal amount of AB113 dye from synthetic wastewater using UV/H2O2/Fe3O4 process obtained 95.51% in optimal condition. Therefore, this method has an effective potential in AB113 removal and can be applied for removal of this dye from industrial wastewater

Evaluation of almond shells magnetized by iron nano-particles for nitrate removal from Aqueous Solution: study of adsorption isotherm

زمینه: یکی از شایع‌ترین آلاینده‌های محیط زیست که در آب‌های زیرزمینی و سطحی وجود دارد نیترات است. غلظت بالای نیترات در آب آشامیدنی سبب بیماری‌هایی مثل متهموگلوبین در کودکان، سرطان معده و سقط جنین می‌شود. هدف از این مطالعه بررسی ایزوترم جذب کربن پوست بادام فعال شده با نانو ذرات مغناطیسی آهن و بررسی کارایی آن در حذف نیترات از محیط‌های آبی بوده است. روش بررسی: این مطالعه به روش تجربی انجام گرفت. مرفولوژی جاذب سنتز شده با استفاده از روش‌های FESEM و BET مورد آنالیز قرار گرفت. پارامترهای موثر بر فرایند جذب یون نیترات از جمله pH (8-4)، میزان جاذب(1-25/0 گرم در لیتر)، غلظت اولیه یون نیترات(400-25 میلی گرم در لیتر) و زمان تماس(100-20 دقیقه) مورد بررسی قرار گرفت. در این مطالعه از روش تاگوچی جهت تعیین حجم نمونه و آنالیز آماری استفاده شد. یافته: یافته های حاصل از روش‌های FESEM و BET تایید کرد که نانوذرات مغناطیسی آهن در جاذب سنتز شده دارای اندازه متوسطnm 27-23 و سطح ویژه برابر با g/m2 480/105 بوده است. نتایج نشان داد که درpH بهینه برابر با 4 و زمان تعادل 20 دقیقه، کارایی جذب با افزایش مقدار جاذب تا g/l 1و کاهش غلظت اولیه یون نیترات افزایش یافت (6/4 86/85 ). نتایج ایزوترم تعادلی نشان داد که فرآیند جذب نیترات از ایزوترم لانگمیر (924/0=R2) پیروی می‌کند. نتیجه‌گیری: یافته‌ها نشان دادند که پوست بادام فعال شده با نانوذره آهن از توانایی مطلوبی در حذف یون نیترات از محلول های آبی برخوردار است. بنابراین با استفاده از این فناوری نسبتا راحت و ساده، می توان گام موثری را در حذف نیترات آبها برداشت

Photocatalytic degradation of catechol in aqueous solutions: a comparison between UV/Fe2O3 and Fe2O3/sunlight processes

Phenols and phenolic compounds are widely used in everyday life and industry. Environmental stability, solubility in aqueous medium and high toxicity of these compounds are due to their high attention. The purpose of this study is the removal of catechol from wastewater based on the comparative use of two photocatalytic hematite/UV and hematite/sunlight processes. In this experimental laboratory study, the hematite nanoparticles are used with the separate application of UV and sunlight to reduce 10-50 mg L-1 concentration of catechol. The effect of parameters such as hematite concentration, reaction time and pH is studied on the catechol removal efficiency of both processes. The 6-W UV lamp as well as UV-A sunlight is used for radiation on the reactor contents. The remaining catechol concentration in the samples is measured by spectrophotometer within the wavelength of 600 nm. The best catechol removal efficiency by UV/Fe2O3 and Fe2O3/sunlight processes is 92.3% and 88% obtained at pH = 2, contact time of 60 min, hematite concentration of 4.0 g L-1 and catechol concentration of 50 mg L-1. UV/Fe2O3 process with 0.4 g L-1 Fe2O3 obtained COD removal of 71.3%, while sunlight/Fe2O3 process achieved lower COD removal of 50.9%. The results showed that UV/Fe2O3 and Fe2O3/sunlight photocatalytic processes have a good potential in catechol removal from aqueous solutions at pilot scale. However, statistical analysis of results did not show a significant difference between the processes. Therefore, it is proposed to study the performance of these processes as a clean and environmentally friendly practice in full scale with real wastewater

Comparison of the Efficiency of Ultraviolet/Zinc Oxide (UV/ZnO) and Ozone/Zinc Oxide (O-3/ZnO) Techniques as Advanced Oxidation Processes in the Removal of Trimethoprim from Aqueous Solutions

Nowadays, advanced oxidation processes, particularly photocatalyst process and catalytic ozonation by ZnO nanoparticles, are the most efficient method of eliminating pharmaceuticals. The purpose of this study was to compare the efficiency of ultraviolet/zinc oxide (UV/ZnO) and ozone/zinc oxide (O-3/ZnO) techniques as advanced oxidation processes in the removal of trimethoprim (TMP) from aqueous solutions. The process consisted of 0.6 g/L of ozone (O-3), pH = 7.5 +/- 0.5, TMP with a concentration of 0.5-5 mg/L, ZnO with a dose of 50-500 mg/L, 5-30 min reaction time, and 30-180 min contact time with UV radiation (6 W, 256 nm) in a continuous reactor. The high removal efficiency was achieved after 25 minutes when ZnO is used in 1 mg/L TMP under an operational condition at pH 7.5. When the concentration of the pollutant increased from 0.5 to 1, the average removal efficiency increased from 78% to 94%, and then, it remained almost constant. An increase in the reaction time from 5 to 25 minutes will cause the average elimination to increase from 84% to 94%. The results showed that the efficiency of O-3/ZnO process in the removal of TMP was 94%, while the removal efficiency of UV/ZnO process was 91%. The findings exhibited that the kinetic study followed the second-order kinetics, both processes. With regard to the results, the photocatalyst process and catalytic ozonation by ZnO nanoparticles can make acceptable levels for an efficient posttreatment. Finally, this combined system is proven to be a technically effective method for treating antibiotic contaminants

Evaluation of sulfadiazine(Sdz) removal from wastewater by persulfate activated with iron sulfate

In this study, removal of an antibiotic (SDZ) from wastewater using an advanced oxidation process of persulfate (PS) in the presence of iron sulfate (S2O8 –2/Fe+2) was investigated. The operational variables such as; the effect of pH, contact time, iron and PS ion concentrations and initial concentration of SDZ on the efficiency of SDZ removal was studied. High performance liquid chromatography (HPLC) was used for the analysis and monitoring of SDZ concentration. It was found that the highest rates of SDZ removal were found to be 95.83±1.342%, 87.15±0.929% and 69.09±0.848%, respectively, for initial SDZ concentration of 0.08, 0.2 and 0.4 mmol. The results showed that the S2O8 –2/Fe+2 system would be optimized by contact time of 60 min, pH 4 and iron to PS molar ratio of 1. Therefore, these findings would help to better apply the AOPs to remove recalcitrance pollutants such as SDZ from wastewater

Simultaneous monitoring of SARS-CoV-2, bacteria, and fungi in indoor air of hospital: a study on Hajar Hospital in Shahrekord, Iran

The novel SARS-CoV-2 outbreak was declared as pandemic by the World Health Organization (WHO) on March 11, 2020. Understanding the airborne route of SARS-CoV-2 transmission is essential for infection prevention and control. In this study, a total of 107 indoor air samples (45 SARS-CoV-2, 62 bacteria, and fungi) were collected from different wards of the Hajar Hospital in Shahrekord, Iran. Simultaneously, bacterial and fungal samples were also collected from the ambient air of hospital yard. Overall, 6 positive air samples were detected in the infectious 1 and infectious 2 wards, intensive care unit (ICU), computed tomography (CT) scan, respiratory patients' clinic, and personal protective equipment (PPE) room. Also, airborne bacteria and fungi were simultaneously detected in the various wards of the hospital with concentrations ranging from 14 to 106 CFU m(-3) and 18 to 141 CFU m(-3), respectively. The highest mean concentrations of bacteria and fungi were observed in respiratory patients' clinics and ICU wards, respectively. Significant correlation (p < 0.05) was found between airborne bacterial concentration and the presence of SARS-CoV-2, while no significant correlation was found between fungi concentration and the virus presence. This study provided an additional evidence about the presence of SARS-CoV-2 in the indoor air of a hospital that admitted COVID-19 patients. Moreover, it was revealed that the monitoring of microbial quality of indoor air in such hospitals is very important, especially during the COVID-19 pandemic, for controlling the nosocomial infections

A systematic review on environmental perspectives of monkeypox virus

Monkeypox (MPX) is one of the common infections between humans and animals that caused by a virus belonging to the Orthopoxvirus genus. The Monkeypox virus (MPXV) outbreak is a global crisis triggered by environmental factors (virus, wastewater, surface, air) and amplified by the decisions of government officials and communities. The aim of this systematic review is to describe the environmental perspectives of MPXV with emphasis on risk assessment to prevent and control a new pandemic. Five online databases including Web of Science, PubMed, Scopus, Science Direct and Google Scholar were searched from 1990 to October 2022. Among 120 records, after the screening, four studies were included in the systematic review. The systematic review revealed that the possibility of MPXV transmission through wastewater, air, and the contaminated surfaces is a significant concern and its detection and destroying will play a major role in controlling the spread of the virus. Poxviruses have a high environmental stability, but are sensitive to all common chemical disinfectants. In conclusion, this study revealed that the environmental surveillance can be used as a complementary tool for detecting pathogens circulation in communities. This implies that the monitoring of environmental perspectives of MPXV can provide new awareness into virus transmission routes as well as the role of stakeholders and public health policies in MPXV risk management