RESUMEN
The presence of trace metals in wastewater brings serious environmental pollution that threatens human health as well as the ecosystem throughout the world due to their non-biodegradability nature. The present study focuses on the bioremediation of toxic trace metals, namely arsenic (As), cadmium (Cd), and chromium (Cr), using Acalypha wilkesiana leaf raw biomass. The optimization of various process variables was done to determine the removal percentage of trace metal using Acalypha wilkesiana leaf raw biomass, and the optimum conditions were an adsorbent dose of 0.5 g, contact time 10 h, 8 h, and 10 h, process temperature 30 °C, initial concentration of trace metal as 30 µg/L, 30 mg//L, and 40 mg/L, and pH of 7.5, 7 and 7.5 for As5+, and Cd2+ and Cr6+, respectively. Acalypha wilkesiana leaf raw biomass is characterized using a scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transformation infrared spectroscopy (FTIR), zeta potential before and after adsorption of the trace metal ions. The study was well fitted for the equilibrium data for Langmuir isotherm for As5+, Cd2+, and Cr6+, Freundlich for As5+, Dubinin-Radushkevinch (D-R) for Cr6+, and Temkin for As5+ and Cr6+. The adsorption of all three trace metals was confirmed by the kinetics and thermodynamic studies to be following pseudo-second-order kinetics with endothermic as well as spontaneous processes, respectively. Thus, the present study indicates Acalypha wilkesiana leaf raw biomass as an effective and efficient novel biosorbent to remediate different trace metals from aqueous systems with its possible application in existing and novel methods for wastewater management.
RESUMEN
The non-scientific disposal of antibiotics has resulted in massive contamination of the bioactive molecules in the aquatic ecosystem. The presence of antibiotics in the effluents limits the biodegradation of micropollutants by affecting the micro-ecological balance. Hence this study aims to remove doxycycline antibiotics from wastewater using biochar. Elemental analysis of the biochar revealed C, Si and N as most abundant content while BET analysis confirmed the mesoporous nature of the adsorbent. The XRD and Raman spectra confirmed amorphic sp2 carbon dominant structure in the biochar. The adsorption mechanism was predicted, correlating the charge distribution and FTIR analysis. The effects of different process parameters were studied using CCD, ANOVA, and RSM. Moreover, the different kinetic models revealed that the pseudo-second-order kinetics model was the best fit and film layer diffusion was the dominant contributor. The isotherm study indicated the high adsorption capacity of the biochar and its non-ionic nature. Thermodynamics study established the spontaneity and exothermic nature. The results suggested no significant change in antibiotic removal efficiency across different system (pond water (97.13%), river water (98.11%), seawater (96.84%), tap water (99.13%), and distilled water (99.74%)). For the desorption of the antibiotic from the biochar surface, 90% ethanol was the most efficient (98.9%), and upon recrystallization by solvent evaporation, 98.7% of the antibiotic of the initial load was recovered. Hence, the implementation of this described process would enable resource recovery along with water treatment, which is not possible with existing approaches. The cost analysis of the whole process revealed that biochar preparation was the bulk expense and the process would be self-sustainable even if the price of the recovered antibiotic would be set at less than half ($41/kg) of the current market price ($94/kg) of the API. Thus, the process endorses a successful circular economy approach toward societal and economic sustainability.
Asunto(s)
Antibacterianos , Doxiciclina , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua , Adsorción , Antibacterianos/análisis , Antibacterianos/química , Carbón Orgánico/química , Doxiciclina/análisis , Doxiciclina/química , Ecosistema , Cinética , Oryza/química , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/química , Eliminación de Residuos Líquidos/métodosRESUMEN
The vast usage of synthetic plastics has led to the global problem of plastic pollution which in turn has positively impacted the concerns regarding microplastic pollution. The major factor responsible for the increased level of pollution is the smaller size of microplastics which helps in its transportation across the globe. It has been found in most remote areas like glaciers and Antarctic regions where it is difficult for other contaminants to reach. This is ensured by the physicochemical cycle of plastic. They can either be produced for different applications or generated through the fragmentation of large plastic particles. Different studies have shown the accumulation of microplastics in different organisms, especially in aquatic animals leading to their entry into the food chain. The ultimate fate of the microplastics is accumulation inside the human body posing the risk of different health conditions like cancer, diabetes, and allergic reactions. The present review summarizes a detailed discussion on the current status of microplastic pollution, their effect on different organisms, and its impact on human health with a case study on the human health risk assessment for analyzing the global rate of microplastic ingestion.