A Novel Combined Treatment Process of Hybrid Biosorbent–Nanofiltration for Effective Pb(II) Removal from Wastewater

The untreated effluents discharged by different industries, such as metallurgy, fertilizers, pesticide, leather, mining, electroplating, surface finishing, aerospace, and electroplating, have increased the risk of the contamination of bodies of water by heavy metals. Herein, hybrid biosorbent–nanofiltration processes for Pb(II) removal from wastewater was studied. The hybrid biosorbent was prepared from date seed waste and Ganoderma lucidum. Hybrid biosorbent characterization was performed by SEM and FTIR. SEM micrographs showed that the HB surface is irregular. For the adsorption studies, various sorption parameters were optimized. The maximum biosorption capacity of immobilized heat-inactivated hybrid biosorbent was 365.9 mg/g, with the Langmuir isotherm model to present the best fit. Desorption experiments were conducted for regenerating immobilized heat-inactivated hybrid biosorbent for three consecutive cycles using different desorption agents, with acetic acid to be the optimum. Going a step further, nanofiltration was also applied as a post-treatment process to elevate the remediation effectiveness for wastewater of high Pb(II) initial concentrations. The reasonably low cost and high removal of Pb(II) make hybrid biosorbent–nanofiltration processes a prosperous and potentially attractive hybrid approach against heavy-metal-polluted wastewater.

Waste heaps in the urban environment as negative factors of urbanization

Urbanization in Ukraine has led to the development of the Lviv-Volyn coal basin. One of the main negative factors in the operation of coal basins are mine dumps. In addition to environmental hazards, waste heaps of coal mines violate the attractiveness and aesthetics of towns. The wastewater from waste heaps is a secondary factor in reducing the environmental safety of the coal-mining region. These waters are concentrated at the foot of landfills forming the man-made reservoirs. The research presents the negative factors of mine dumps and the results of physical and chemical analysis of subtericone wastewater and its impact on environmental pollution. It is established that the most polluted is the wastewater from waste heaps of the Mezhyrichanska mine which is caused by its operating process. The man-made polluted wastewater from heaps is a secondary factor in reducing the level of ecological danger of the coal-mining region. These waters are concentrated at the foot of landfills in the form of man-made reservoirs. The aim of the research is to indicate the negative factors of urban waste heaps by studying the physical and chemical properties of underspoil waters within the cities of Chervonograd and Novovolynsk.

Utilizing industrial by-products as eco-friendly adsorbent for phosphate removal: An experimental approach

One of the widely present elements in the groundwater and surface water is phosphate due to two reasons; firstly, it is available at high concentrations in the soil, and secondly, it is widely available in wastewaters (industrial, agricultural and domestic wastewaters). Although phosphate causes many problems to the aquatic environment, eutrophication is the most severe problem due to its effects on water quality, economy, and health. Therefore, a number of studies have been made to evaluate the ability of different remedies to eliminate phosphates from wastewaters. Recently, phosphorus extraction may be achieved by filtering the contaminated solution. However, the cost of filtration materials is still high. Due to this reason, research to date has focused on employing inexpensive materials to reduce the cost of the filtering process. In this research, a by-product of steel manufacturing, kiln bottom ashes, was used to extract phosphates from polluted wastewater, considering the impacts of a number of operating parameters, such as to achieve the best possible extraction efficiency for the lowest possible cost. The findings of this study proved the excellent ability of the bottom ash in the extraction of phosphate from wastewater, where it removed more than 90% of 5 mg/L of phosphate after 40 minutes of treatment using 530 mg/L of bottom ash.

Hydrothermal synthesis of magnetic nano-CoFe2O4 catalyst and its enhanced degradation of amoxicillin by activated permonosulfate

Advanced oxidation process (AOP) has attracted widespread attention because it can effectively remove antibiotics in water, but its practical engineering application is limited by the problems of the low efficiency and difficult recovery of the catalyst. In the study, nano-spinel CoFe2O4 was prepared by hydrothermal method and served as the peroxymonosulfate (PMS) catalyst to degrade antibiotic amoxicillin (AMX). The reaction parameters such as CoFe2O4 dosage, AMX concentration, and initial pH value were also optimized. The reaction mechanism was proposed through free radical capture experiment and possible degradation pathway analysis. In addition, the magnetic recovery performance and stability of the catalyst were evaluated. Results showed that 85.5% of AMX could be removed within 90 min at optimal conditions. Sulfate radicals and hydroxyl radicals were the active species for AMX degradation. Moreover, the catalyst showed excellent magnetism and stability in the cycle experiment, which has great potential in the AOP treatment of antibiotic polluted wastewater.

Testing an aerobic fluidized biofilm process to treat intermittent flows of oil polluted wastewater

An aerobic fluidized biofilm process of treating oil-polluted wastewater has been studied. A series of batch experiments were conducted using synthetic wastewater and the kinetic coefficients were evaluated. The maximum rate of substrate utilization per unit mass microorganisms (K) was 1.6 days-1, the substrate concentration at one-half the maximum growth rate (Ks) was 26 mg/L, the maximum specific growth rate (m) was 1.0 days-1, the ratio of the mass cells formed to the mass of substrate consumed (Y) was 0.61, and the endogenous decay coefficient (Kd ) was 0.044 days-1. The kinetic coefficients obtained were within the range of municipal wastewater. It was observed that up to 1500 mg/L oil (Motor oil SAE–40) could be degraded in a fluidized bed bioreactor (FBBR). The experiments, however, were limited to the oil concentration within a range of 1000-2600 mg/L. Average biofilm thickness () under specific conditions was found to be 22 m and average oil degradation rate of 0.053 mg oil/mg biomass/hour was measured in the FBBR. The results also support that the increase in the concentration of oil in the treatment process reduced significantly the degradation rate of non-oil carbon.

Comparing the effect of zinc oxide and titanium dioxide nanoparticles on the ability of moderately halophilic bacteria to treat wastewater

This study evaluates the ability of moderately halophilic bacterial isolates (Serratia sp., Bacillus sp., Morganella sp., Citrobacter freundii and Lysinibacillus sp.) to treat polluted wastewater in the presence of nZnO and nTiO2 nanoparticles. In this study, bacteria isolates were able to take up nZnO and nTiO2 at concentrations ranging from 1 to 50 mg/L in the presence of higher DO uptake at up to 100% and 99%, respectively, while higher concentrations triggered a significant decrease. Individual halophilic bacteria exhibited a low COD removal efficiency in the presence of both metal oxide nanoparticles concentration ranged between 1 and 10 mg/L. At higher concentrations, they triggered COD release of up to − 60% concentration. Lastly, the test isolates also demonstrated significant nutrient removal efficiency in the following ranges: 23–65% for NO3− and 28–78% for PO43−. This study suggests that moderately halophilic bacteria are good candidates for the bioremediation of highly polluted wastewater containing low metal oxide nanoparticles.

Possibility of Removing Pb and Cd from Polluted Water by Modified Fly Ash

In this study, fly ash (FA) was modified by sodium hydroxide to prepare a new adsorption material (IP) and treat Pb2+- and Cd2+-polluted wastewater. The effect of preparation parameters (mass ratio of FA/NaOH and modification temperature) on IP adsorption performance was investigated. The results indicated that the IP4 showed the highest adsorption capacity prepared at the FA/NaOH mass ratio of 1 : 2 and the roasting temperature of 250°C. The IP4 was characterized by SEM, EDX, XRD, and FTIR analyses. The results showed that the surface morphology and microstructure of FA were significantly changed. Furthermore, in order to study the adsorption performance of Pb2+ and Cd2+ on IP4, the different initial concentrations of Pb2+ and Cd2+, pH, and contact time were analyzed, and the results indicated that IP4 has excellent adsorption capacity for heavy metals. In addition, kinetic model results demonstrated that the adsorption behavior of Pb2+ and Cd2+ on IP4 was better described by a pseudo-second-order model.

Synthesis and Characterization of C/ZnO Nanocomposite: Adsorption Isotherm of a Reactive Green from Aqueous Solutions

The study demonstrates that Nanocomposite activated Carbone decorated zinc oxide is indeed viable, cost effective adsorbent materials for the adsorptive removal of Reactive Green (RG) dye from polluted wastewater with over 90% removal dye. The adsorption of RG dye onto decorated carbon ZnO nanoparticle was found to be highly dependent on equilibrium time, initial RG dye concentration, adsorbent mass and. The quantity of RG dye uptake (mgg-1) was found to rise through increase in primary dye concentration. Percent removal of RG dye was found to increase with increase in contact time, adsorbent amount. The data indicated that the model Freundlich gave a better fit to the experimental result than the model Langmuir with high correlation coefficients (R2 = 0.964). This suggests that multi-layer adsorption occurs which is in agreement with the best applicability of the isotherm Freundlich.