Prashant Pandey

β-lactam antibiotics are frequently investigated as emerging contaminants in aquatic environments because of their widespread use and incomplete removal in conventional treatment systems. In this study, sulfur- and nitrogen-co-doped activated carbon (S,N-AC) was prepared from rice husk through carbonisation, KOH activation, and thiourea-assisted heteroatom functionalisation. Pristine rice husk (PRH), rice husk biochar (RHB), and S,N-AC were characterised using nitrogen adsorption-desorption, SEM-EDX, FTIR, XRD, TGA, and zeta-potential measurements. S,N-AC exhibited a BET surface area of 1126 m² g⁻¹ and a developed micro–mesoporous structure. Its adsorption performance was evaluated for cephalexin, cefprozil, and cefixime in single-solute and ternary systems. The Langmuir model provided the highest correlation for S,N-AC, with fitted qmax values of 285, 260, and 295 mg g⁻¹ for cephalexin, cefprozil, and cefixime, respectively. Kinetic data were described using pseudo-first-order, pseudo-second-order, and intraparticle-diffusion models. Thermodynamic parameters indicated spontaneous and exothermic adsorption over the investigated temperature range. In the ternary system, adsorption capacities decreased relative to the corresponding single-solute experiments, consistent with competition for adsorption sites. XPS and surface-charge measurements were used together with textural and kinetic results to discuss possible adsorption interactions. The results indicate that S,N-AC has potential for further investigation as a rice-husk-derived adsorbent for antibiotic-contaminated aqueous systems.

Rice husk-derived biochars with progressively modified surface properties were investigated for adsorbing flucloxacillin sodium (FLX-Na) from aqueous solution. Four materials—rice husk biochar (RHB), nitrogen-functionalized RHB (N-RHB), magnetic nitrogen-functionalized RHB (MN-RHB), and magnetic nitrogen/sulfur-functionalized RHB (MN,S-RHB)—were prepared and characterised using morphological, structural, textural, and surface-chemical techniques. The sequential preparation routes produced materials with different surface areas, pore structures, and surface functionalities. FLX-Na adsorption increased in the order RHB < MN-RHB < N-RHB < MN, S-RHB, with the highest equilibrium adsorption capacity obtained for MN,S-RHB (118.6 mg g⁻¹). Because chemical activation and a higher carbonisation temperature were introduced only for MN,S-RHB, the higher uptake is interpreted as an effect of the combined modification route rather than being attributed specifically to N/S co-doping. Kinetic and equilibrium data were described using several empirical models, with the pseudo-second-order and Sips models giving the highest coefficients of determination among the tested fits. The adsorption capacity of MN,S-RHB decreased from 84.60 ± 1.30 mg g⁻¹ in deionised water to 60.30 ± 1.80 mg g⁻¹ in a mixed inorganic/humic-acid matrix, corresponding to 71.3% capacity retention. Spectroscopic changes after adsorption were consistent with changes in the surface chemical environment, while the matrix experiments indicated that coexisting inorganic ions and dissolved organic matter influenced adsorption performance. These results show that the combined physicochemical modification route altered the adsorption behaviour of rice husk-derived biochar under the investigated conditions.

Excessive exploitation, negligence, non-degradable nature, and physical and chemical properties of plastic waste have resulted in a massive pollution load into the environment. Consequently, plastic entres the food chain and can cause serious health issues in aquatic animals and humans. The present review summarizes currently reported techniques and approaches for the removal of plastic waste. Many techniques, such as adsorption, coagulation, photocatalysis, and microbial degradation, and approaches like reduction, reuse and recycling are potentially in trend and differ from each other in their efficiency and interaction mechanism. Moreover, substantial advantages and challenges associated with these techniques and approaches are highlighted to develop an understanding of the selection of possible ways for a sustainable future. Nevertheless, in addition to the reduction of plastic waste from the ecosystem, many alternative opportunities have also been explored to cash plastic waste. These fields include the synthesis of adsorbents for the removal of pollutants from aqueous and gaseous stream, their utility in clothing, waste to energy and fuel and in construction (road making). Substantial evidence can be observed in the reduction of plastic pollution from various ecosystems. In addition, it is important to develop an understanding of factors that need to be emphasized while considering alternative approaches and opportunities to cash plastic waste (like adsorbent, clothing, waste to energy and fuel). The thrust of this review is to provide readers with a comprehensive overview of the development status of techniques and approaches to overcome the global issue of plastic pollution and the outlook on the exploitation of this waste as resources.

Tourism is one of the lifelines in nations for their strong economy. Through the expansion of tourism industry, enormous amounts of plastic materials are disposed that have detrimental effects on environment, animal and human health. The present study demonstrates the role of tourists on generation of plastic waste and further statistical approach was used to investigate the impact of knowledge, behaviour, and attitude of tourists towards generation of plastic waste. Result shows that the tourists play key role in generating plastic waste at outdoor places which is a serious issue that could block drainage ways in city which leads to many waters born disease. The study highlights that the awareness can make certain changes in plastic waste generation and can bridge the knowledge–practice gap. Moreover, the circular economy can offer opportunity to exploit plastic waste into various decorative and useful products that can generate income to local community and help to reduce plastic wastes. It is also important to highlight that the government needs to take care of surveillance in the market on using plastic bags either by sellers or consumers.

Waste water generated from vehicle service/wash centres are serious issue in now a day. This become critical if waste water from unauthorized service centres is discharged to the river stream which has potential to degrade river water quality and its depended wildlife. The present study demonstrates that the river water chemistry changes drastically and river become more worse after the influx of the discharged waste water from vehicle service/wash centres. Significant number of surfactants, oil & grease, nitrate and nitrite are detected in both the river water while they are passing through the Dehradun city stretch, Uttarakhand- India. Further, service centres are also the major contributor of the heavy metals in river water, however the concentration of Cu, Mn, Fe, Cu, Zn, As, Cd, Pb, and Ni under acceptable limits at upper stretch of the Rispana and Bindal. Whereas, the study reveals that the HPI value of the metals are > 30 at each location which indicates their unsuitability for utility. Moreover, HI values are estimated under unity which are 0.00845, 0.00655, 0.00542, 0.033 for upper stretch -Rispana, upper stretch-Bindal, average effluent discharge from vehicle service centres and downstream of river, respectively indicates less possible threat to non-carcinogenic effects. In upper stretch of both the rivers, cancer risk values of heavy metals such as As, Cr, and Ni are estimated under 1*10 -4 while other exceeds show the probability of cancer if consumed for long term. In best of our knowledge this is the first study, therefore no data is available to compare and observe the changes, if occur.Additionally, more studies are needed to understand and establish the relationship between contaminated river water quality and its impact on dependent wildlife.