This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or adsorption capacity. The prepared adsorbent was evaluated for the adsorption of cadmium (Cd) and chromium (Cr) from aqueous media with the batch experiment method. Factors that affect the adsorption process are pH, initial concentration, contact time and adsorbent dose. The analysis of Cd and Cr was performed by using atomic absorption spectrometry (AAS), while the characterization of the adsorbent was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that there is a significant difference before and after corncob activation and doping with CeO2 nanoparticles. The maximum removal for both Cd and Cr was at a basic pH with a contact time of 60 min at 120 rpm, which is 95% for Cd and 88% for Cr, respectively. To analyze the experimental data, a pseudo-first-order kinetic model, pseudo-second-order kinetic model, and intra-particle diffusion model were used. The kinetic adsorption studies confirmed that the experimental data were best fitted with the pseudo-second-order kinetic model (R2 = 0.989) and intra-particle diffusion model (R2 = 0.979). This work demonstrates that the cerium oxide/corncob nanocomposite is an inexpensive and environmentally friendly adsorbent for the removal of Cd and Cr from wastewater.
Radiolytic degradation of lindane (1.0 mg.L-1) in aqueous phase was carried out through gamma (γ) irradiation by 60Co source with 1-12 kGy dose range. The γ- radiation dose was optimized and maximum degradation of lindane was achieved with 10kGy at ambient temperature. The catalytical effect of TiO2 and Fe2O3 on degradation efficiency was investigated. The results demonstrate that degradation was enhanced by addition of catalyst. The maximum degradation of lindane was achieved with TiO2 as compare to Fe2O3. Maximum degradation (%) of lindan was 99% with TiO2; 95% with Fe2O3 and 90.2% without catalyst was achieved at 10 kGy doze. Change in concentration of lindane as result of irradiation was verified by HPLC equipped with UV detector. Lindane degradation products extracted and pre-concentrated through Solid Phase Micro-Extraction (SPME) technique. A reaction mechanism was envisaged by analyzing the resulting by-products using a Gas Chromatography-Mass Spectrometry (GC–MS) technique.
ABSTRACT The present study was conducted to investigate the allelopathic effects of Prosopis juliflora (Sw.) DC. (Mesquite) on various growth parameters of three promising grass species (Cenchrus ciliaris, Panicum antidotale and Panicum maximum) on the Potohar Plateau, Pakistan, under nursery conditions. The experiment was carried out under a completely randomized design with two factors and three replicates. Different concentrations of the foliage aqueous extract of P. juliflora were prepared and their effect was studied on root length, shoot length, fresh and dry biomass of tested grass species. All grass species showed a concentration dependent inhibition. However, among all grasses, C. ciliaris was affected most severely whereas P. antidotale was the least affected grass species. This indicates an adverse effect of mesquite leaf on grass growth which is directly proportional to the increase in the extraction level of the mesquite leaf. These outcomes suggest that mesquite foliage contains allelochemicals that had inhibitory effect on grass growth.
Abstract The scientific report assessed the impact of Nalla Lai wastewater on the groundwater quality of Rawalpindi city, Pakistan. A total of 19 wastewater and 49 groundwater samples were collected during September and October 2016 and have been analyzed in the laboratory to detect different water quality parameters. The results revealed that BOD (biological oxygen demand), COD (chemical oxygen demand), iron, and cadmium values in many wastewater samples were beyond the recommended value of the National Environmental Quality Standards 1997 (NEQs, 1997). In groundwater samples, the results of iron, cadmium, manganese, zinc, TDS (total dissolved solids), pH, color, and hardness were found elevated from the standard values in one or more samples as compared with the National Standard for Drinking Water Quality, 2010 (NSDWQ, 2010). The decreasing metal concentration order in groundwater samples was iron > zinc > manganese > copper > cadmium. Very interestingly, hardness was found at elevated levels in 75% of investigated groundwater samples. Microbiological contamination was detected in 83% of the analyzed groundwater samples. The study revealed the percolation of heavy metals and microbial contamination in the bore water, tube wells, hand pumps, springs, and hand-dug wells located nearby the Nalla Lai wastewater stream.
Agricultural organic matter is a major component of organic waste on earth that significantly contributes in environmental pollution.The conversion of organic waste into biochar and addition to soil is the recommended strategy to reduce the negative environmental effects of organic waste and to increase the soil fertility.Therefore, in this study, we evaluated the changes in nutrient concentrations, rice yield and microbial community structure in a Psammaquent and Plinthudult at harvest following incorporation of biochar derived from wheat straw.Wheat straw biochar generated at 300-500 ˚C under oxygen limited conditions was applied, in a greenhouse experiment to a Psammaquent and Plinthudult at a rate of 3% weight/weight (w/w).The biochar addition to both types of soil significantly increased the soil pH from 4.2 to 6.2 and 4.7 to 6.7, total nitrogen by 135 and 37%, and organic carbon by 90 and 80%, in the Psammaquent and Plinthudult, respectively as compared to the respective controls.The dissolved organic nitrogen (DON) was decreased by 24 and 15% and dissolved organic carbon (DOC) by 40 and 44% in Psammaquent and Plinthudult, respectively.The biochar decreased the concentrations of K leached by 24%, B by 25%, Cu by 80%, Mn by 37% and Zn by 33% in the Psammaquent and B by 50%, Cu by 60%, Fe by 43%, Mn by 69% and Zn by 83% in the Plinthudult as compared to the controls.The wheat straw biochar addition to two soils increased the accumulation of Mn, Mo, Na and Zn in both rice straw and grain and decreased the leaching of nutrients, organic carbon and nitrogen at rice harvest and increased the leaching of Ca, Na, and Mg in both Psammaquent and Plinthudult.The biochar increased the pH, TOC and nitrogen in both soils.The biochar significantly changed the PLFA concentration indicating different microbial community pattern in soils growing rice compared to their controls.Thus, the results indicated that wheat straw biochar increased the productivity of rice in the Plinthudult and Psammaquent.
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