A critical review on the removal of toxic pollutants from contaminated water using magnetic hybrids.

The persistence of organic/inorganic pollutants in the water has become a serious environmental issue. Among the different pollutants, dyes and heavy metal pollution in waterways are viewed as a global ecological problem that can have an impact on humans, plants, and animals. The necessity to develop a sustainable and environmentally acceptable approach to remove these toxic contaminants from the ecosystem has been raised. In the past two decades, rapid industrialization and anthropogenic activities in developed countries have aggravated environmental pollution. Industrial effluents that are discharged directly into the natural environment taint the water, which has a consequence for the water resources. Magnetic nanohybrids are broadly investigated materials used in the adsorption and photocatalytic degradation of poisonous pollutants present across water effluents. In the present review, the toxic health effects of heavy metals and dyes from the water environment have been discussed. This paper reviews the role of magnetic nanohybrids in the removal of pollutants from the water environment, providing an adequate point of view on their new advances regarding their qualities, connection methodologies, execution, and their scale-up difficulties.

Recent advances and discoveries of microbial-based glycolipids: Prospective alternative for remediation activities.

Surfactants have always been a prominent chemical that is useful in various sectors (e.g., cleaning agent production industry, textile industry and painting industry). This is due to the special ability of surfactants to reduce surface tension between two fluid surfaces (e.g., water and oil). However, the current society has long omitted the harmful effects of petroleum-based surfactants (e.g., health issues towards humans and reducing cleaning ability of water bodies) due to their usefulness in reducing surface tension. These harmful effects will significantly damage the environment and negatively affect human health. As such, there is an urgency to secure environmentally friendly alternatives such as glycolipids to reduce the effects of these synthetic surfactants. Glycolipids is a biomolecule that shares similar properties with surfactants that are naturally synthesized in the cell of living organisms, glycolipids are amphiphilic in nature and can form micelles when glycolipid molecules clump together, reducing surface tension between two surfaces as how a surfactant molecule is able to achieve. This review paper aims to provide a comprehensive study on the recent advances in bacteria cultivation for glycolipids production and current lab scale applications of glycolipids (e.g., medical and waste bioremediation). Studies have proven that glycolipids are effective anti-microbial agents, subsequently leading to an excellent anti-biofilm forming agent. Heavy metal and hydrocarbon contaminated soil can also be bioremediated via the use of glycolipids. The major hurdle in the commercialization of glycolipid production is that the cultivation stage and downstream extraction stage of the glycolipid production process induces a very high operating cost. This review provides several solutions to overcome this issue for glycolipid production for the commercialization of glycolipids (e.g., developing new cultivating and extraction techniques, using waste as cultivation medium for microbes and identifying new strains for glycolipid production). The contribution of this review aims to serve as a future guideline for researchers that are dealing with glycolipid biosurfactants by providing an in-depth review on the recent advances of glycolipid biosurfactants. By summarizing the points discussed as above, it is recommended that glycolipids can substitute synthetic surfactants as an environmentally friendly alternative.

Surface improved agro-based material for the effective separation of toxic Ni(II) ions from aquatic environment.

In this present study, a novel and low cost surface improved material was prepared from the farm waste material (Borassus flabellifer male inflorescence) and its surface was enhanced by the sulphuric acid treatment to intensify the Ni(II) ions adsorption. The adsorption individualities such as availability of functional groups, essential elements and the exterior side and structural properties of the material were assessed by the FT-IR, EDX, SEM and XRD investigation. The impact of varied adsorption influencing parameters on Ni(II) ions adsorption was studied and optimized as pH - 6.0, biosorbent dosage - 1.5 g/L, contact time - 60 min and temperature - 303 K via batch adsorption examination. Modeling examinations were carried with varied adsorption isotherm (Langmuir, Freundlich, Fritz-Schlunder and Temkin) and kinetic models (Pseudo-first order, Pseudo-second order and Elovich kinetics). Thermodynamic studies were carried out at varied Ni(II) ions concentrations (25 mg/L - 150 mg/L) and temperatures (303 K-333 K) to explain the nature of Ni(II) ions adsorption on Borassus flabellifer male inflorescence. The prepared material has shown the most suitable Ni(II) ions adsorption results for the Langmuir isotherm (R2 = 0.9808) and Pseudo-first order kinetic models (R2 = 0.9735 for 25 mg/L). Thereby, the modeling study revealed that the prepared material has received the Ni(II) ions adsorption capacity (qm) value of 20.31 mg/g and the Ni(II) ions adsorption was physisorption. Thermodynamic results demonstrated that the Ni(II) ions adsorption was immediate, exothermic and favorable at low temperature.

Modeling and Cr(VI) ion uptake kinetics of Sorghum bicolor plant assisted by plant growth-promoting Pannonibacter phragmetitus: an ecofriendly approach.

The research work focuses on the application of Cr(VI)-resistant plant growth-promoting bacteria Pannonibacter phragmetitus for enhancing Cr(VI) uptake by Sorghum bicolor. Significant increase in plant shoot and root characters was found when assisted by P. phragmetitus. The obtained strain showed 700 mg/L of chromium reduction at 24-h incubation. Indole-3 acetic acid (IAA) production by the bacterial strain was found to be 86.45 µg/mL. Pannonibacter phragmetitus solubilized tricalcium phosphate showing maximum solubilizing activity of PSI = 3.31. The qmax of P. phragmetitus was high in the wavelength of 600 nm. Langmuir isotherm best described the Cr(VI) ion uptake by the plant. The RL values reliably reduced with expanding Cr(VI) ion concentration from 25 to 150 mg/L. The outcomes of kinetic studies showed that compared with pseudo first-order, pseudo second-order kinetics better describes the plant Cr(VI) uptake rate. Elovich model describes the increased rates for attaining equilibrium. The equilibrium parameter values for different Cr(VI) ion concentrations range between 0 and 1 which describes the favorable condition for plant metal uptake at different concentrations. Graphical abstract.

Nano-zero valent iron impregnated cashew nut shell: a solution to heavy metal contaminated water/wastewater.

The present research is focused on the removal of Zn(II) ions from aqueous solution using nano zero-valent iron impregnated cashew nut shell (NZVI-CNS). The present system was investigated in batch mode operation. NZVI-CNS was prepared by the liquid-phase reduction process. The results showed that the NZVI-CNS exhibited superior adsorption capacity for the removal of Zn(II) ions. Adsorption isotherm and kinetic models were applied to explain the nature of the adsorption process. Adsorption kinetic data followed the pseudo-first order kinetic model. Moreover, the equilibrium adsorption data were best fitted with a Freundlich model. Langmuir monolayer adsorption capacity was calculated as 94.46 mg of Zn(II) ions/g of NZVI-CNS. The thermodynamic parameters explain that the present adsorption system was measured as feasible and spontaneous. This newly prepared adsorbent can be successfully applied for the different industrial wastewater treatment. Finally, the exploration asks about contemplated that NZVI-CNS has exhibited unrivalled adsorption limit. Additionally, NZVI-CNS is believed to be extremely green and monetarily neighbourly help for wastewater treatment. The results indicate that the feasible approach could be applied in agricultural waste biomass materials for the productive expulsion of heavy metals from aqueous solution and reusing agricultural wastes to facilitate their disposal problem.

Removal of toxic zinc from water/wastewater using eucalyptus seeds activated carbon: non-linear regression analysis.

In the present study, a novel activated carbon was prepared from low-cost eucalyptus seeds, which was utilised for the effectively removal of toxic zinc from the water/wastewater. The prepared adsorbent was studied by Fourier transform infrared spectroscopy and scanning electron microscopic characterisation studies. Adsorption process was experimentally performed for optimising the influencing factors such as adsorbent dosage, solution pH, contact time, initial zinc concentration, and temperature for the maximum removal of zinc from aqueous solution. Adsorption isotherm of zinc removal was ensued Freundlich model, and the kinetic model ensued pseudo-second order model. Langmuir monolayer adsorption capacity of the adsorbent for zinc removal was evaluated as 80.37 mg/g. The results of the thermodynamic studies suggested that the adsorption process was exothermic, thermodynamically feasible and impulsive process. Finally, a batch adsorber was planned to remove zinc from known volume and known concentration of wastewater using best obeyed model such as Freundlich. The experimental details showed the newly prepared material can be effectively utilised as a cheap material for the adsorption of toxic metal ions from the contaminated water.