Achieving Electrochemical-Sustainable-Based Solutions for Monitoring and Treating Hydroxychloroquine in Real Water Matrix

Hydroxychloroquine (HCQ) has been extensively consumed due to the Coronavirus (COVID-19) pandemic. Therefore, it is increasingly found in different water matrices. For this reason, the concentration of HCQ in water should be monitored and the treatment of contaminated water matrices with HCQ is a key issue to overcome immediately. Thus, in this study, the development of technologies and smart water solutions to reach the Sustainable Development Goal 6 (SDG6) is the main objective. To do that, the integration of electrochemical technologies for their environmental application on HCQ detection, quantification and degradation was performed. Firstly, an electrochemical cork-graphite sensor was prepared to identify/quantify HCQ in river water matrices by differential pulse voltammetric (DPV) method. Subsequently, an HCQ-polluted river water sample was electrochemically treated with BDD electrode by applying 15, 30 and 45 mA cm−2. The HCQ decay and organic matter removal was monitored by DPV with composite sensor and chemical oxygen demand (COD) measurements, respectively. Results clearly confirmed that, on the one hand, the cork-graphite sensor exhibited good current response to quantify of HCQ in the river water matrix, with limit of detection and quantification of 1.46 mg L−1 (≈3.36 µM) and 4.42 mg L−1 (≈10.19 µM), respectively. On the other hand, the electrochemical oxidation (EO) efficiently removed HCQ from real river water sample using BDD electrodes. Complete HCQ removal was achieved at all applied current densities; whereas in terms of COD, significant removals (68%, 71% and 84% at 15, 30 and 45 mA cm−2, respectively) were achieved. Based on the achieved results, the offline integration of electrochemical SDG6 technologies in order to monitor and remove HCQ is an efficient and effective strategy.

Remediation of Kalyani River water using plant-bacterial cell synergism

The purpose of this research was to evaluate the potential of plant-immobilized bacterial cells synergism for enhanced remediation of polluted river water. The polluted river water sample was collected from Kalyani river, Uttarakhand, India and characterized by high concentration of COD (1010 mg/l), BOD (230 mg/l), NO3−-N (30 mg/l), PO43−-P (48.9 mg/l), and Pb(1.028 mg/l). This water sample was treated on a lab scale with immobilized bacterial cells and Epipremnum aureum in various treatment setups. The treatment system 3 using a combination of immobilized bacterial cells and Epipremnum aureum had the highest pollutant removal efficiency of all the treatment setups tested. At 96 hours, the total COD, BOD, NO3−-N, PO43−-P and Pb contents of polluted river water sample were reduced to 60 mg/l, 20 mg/l, 2.4 mg/l, 11.7 mg/l, and 0.065 mg/l, respectively. Based on the findings, it is possible to conclude that utilizing plant-immobilized bacterial cell synergism is an environmentally friendly and cost-effective approach for enhanced remediation and rejuvenation of polluted river water. Furthermore, a field-scale application of plant-immobilized bacterial cell synergism via floating wetland construction for on-site treatment of contaminated water on the Kalyani river is recommended.

Characterization of a rare species of Neurospora isolated from a river water sample in China

A fungal isolate (ZZS4408) was obtained from a river water sample in Henan, China, and identified as a member of Neurospora brevispora, a rare species of Neurospora based on its morphological characteristics and ribosomal DNA internal transcribed spacer (rDNA-ITS) sequence. The temperatures suitable for growth of the isolate were 28-37?C with 31?C as the optimum. The growth rates of hyphal tips were 19.1-42.5 (av. 31.9) ?m min-1 at 32?C. The pH suitable for vegetative growth ranged from 5 to 7, with pH 5.5 as the optimum. The heterodisaccharides (sucrose and lactose) and D-alanine were found to be most favorable for vegetative growth of the isolate, as carbon and nitrogen sources, respectively. The vegetative growth of the isolate was more significantly influenced by nitrogen sources compared to carbon sources. N. brevispora could be considered a desirable fungal species for morphodifferentiation studies due to its rapid growth rates under favorable conditions.

Woody plant willow in function of river water protection

Coastal area surrounding the river Ibar, in the area between cities of Kosovska Mitrovica and Leposavic in the north of Kosovo and Metohija, is occupied with seven industrial waste dumps. These dumps were all part of the exploitation and flotation refinement of raw mineral materials, metallurgic refinement of concentrates, chemical industry, industrial refinement and energetic facilities of Trepca industrial complex. The existing waste dumps, both active and inactive, are of heterogenic chemical composition. Its impact on the river water is shown by the content of heavy metals found in it. Removal of lead, cadmium and zinc would be economically unrewarding, regardless of the technology used. Wooden plant that prevails in this area is white willow. This work is focused on the removal of heavy metals (Pb, Cd and Zn) from the water of the river Ibar using white willow. Roots of the willow are cultivated using the method of water cultures in an individual solution of heavy metals and river water sample. The preparation of the samples for analysis was performed by burning the herbal material and dissolving ashes in the appropriate acids. The concentrations of metals were determined by the stripping analysis. In the investigated heavy metal solutions the biomass increase is 25.6% in lead solution, 27.3% in cadmium and 30.7% in zinc solution. The increase of biomass in nutritional solution, without the heavy metals, is 32.4% and in river water sample 27.5%. The coefficient of bioaccumulation in solutions with heavy metals is 1.6% in lead solution, 1.9% in cadmium and 2.2% in zinc solution. Heavy metals accumulation is 18.74 ?g of lead, 20.09 ?g of cadmium and 22.89 ?g of zinc. The coefficient of bioaccumulation of the water samples, that contained 44.83 ?g/dm3 of lead, 29.21 ?g/dm3 of cadmium and 434.00 ?g/dm3 of zinc, during the period of 45 days, was 30.3% for lead, 53.4% for cadmium and 3.9% for zinc. The concentrations of accumulated metals from the river water are 19.01 ?g of lead, 21.85 ?g of cadmium and 23.96 ?g of zinc in grams dry matter. The obtained results indicate that the willow can contribute to the decontamination of moderately contaminated river water from Pb, Cd and Zn.