Agro-morphological changes caused by the accumulation of lead in Corchorus olitorius, a leafy vegetable with phytoremediation properties

Lead (Pb) can enter the food chain through the consumption of contaminated plants and can cause serious health issues. However, research on how Pb accumulation affects morphology of leafy vegetables in South Africa is minimal. This study tested the effect of lead accumulation on vegetative and reproductive traits of Corchorus olitorius.Plants were grown under varying Pb concentrations, and studied for their variation in vegetative and reproductive traits as well as Pb accumulation in leaves, stems and roots. Plants grown within allowable soil concentrations of 150 mg kg–1 Pb accumulated toxic (≥ 10 mg kg–1) Pb in all plant parts without causing any morphological defect, except for a decrease in chlorophyll content. Minor reductions in growth and yield were evident only at 900-1000 mg kg–1 concentration. Pb accumulation increased as its concentration increased in the soil, with a higher accumulation in roots in comparison to aerial parts. In conclusion, C. olitorius can grow and reproduce under toxic Pb levels (≥ 300 mg kg–1) and accumulate toxic amounts of Pb (≥ 10 mg kg–1) without visible morphological defects. Therefore, it is suitable for phytoremediation but unsafe for consumption when it is collected from sites prone to Pb contamination

Wastewater Treatment by a Polymeric Bioflocculant and Iron Nanoparticles Synthesized from a Bioflocculant

Wastewater remains a global challenge. Various methods have been used in wastewater treatment, including flocculation. The aim of this study was to synthesize iron nanoparticles (FeNPs) using a polymeric bioflocculant and to evaluate its efficacy in the removal of pollutants in wastewater. A comparison between the efficiencies of the bioflocculant and iron nanoparticles was investigated. A scanning electron microscope (SEM) equipped with an energy-dispersive X-ray analyzer (EDX) and Fourier transform-infrared (FT-IR) spectroscopy were used to characterize the material. SEM-EDX analysis revealed the presence of elements such as O and C that were abundant in both samples, while FT-IR studies showed the presence of functional groups such as hydroxyl (–OH) and amine (–NH2). Fe nanoparticles showed the best flocculation activity (FA) at 0.4 mg/mL dosage as opposed to that of the bioflocculant, which displayed the highest flocculation activity at 0.8 mg/mL, and both samples were found to be cation-dependent. When evaluated for heat stability and pH stability, FeNPs were found thermostable with 86% FA at 100 °C, while an alkaline pH of 11 favored FA with 93%. The bioflocculant flocculated poorly at high temperature and was found effective mostly at a pH of 7 with over 90% FA. FeNPs effectively removed BOD (biochemical oxygen demand) and COD (chemical oxygen demand) in all two wastewater samples from coal mine water and Mzingazi River water. Cytotoxicity results showed both FeNPs and the bioflocculant as nontoxic at concentrations up to 50 µL

Synthesis of anisotropic PbS nanoparticles using heterocyclic dithiocarbamate complexes

We report the synthesis of lead piperidine and lead tetrahydroquinoline dithiocarbamate (DTC) complexes and their use as single source precursors for the preparation of anisotropic PbS nanoparticles. The complexes were thermolysed in coordinating solvents such hexadecylamime (HDA), tri-n-octylphosphine oxide (TOPO), oleylamine (OA) and decylamine (DA) at various reaction temperatures. The variation of the reaction conditions and precursors produced PbS particles with shapes ranging from spheres to cubes and rods. The size of the particles is generally larger than those synthesized by conventional precursor routes. The electron microscopy and X-ray diffraction data confirm the particles to be very crystalline with the dominant cubic rock salt phase present in all samples. © The Royal Society of Chemistry 2012