पर्यावरण विश्लेषणात्मक रसायन विज्ञान जर्नल

Carnallite processing using reverse flotation has been developed in recent decades. Khur Biabanak is the Iranian greatest Potash complex. Despite developments in the mineral processing technologies, common flotation systems which are used for potash flotation suffer from many disadvantages as high depreciation, wasteful energy usage and low production rate. In this project Jameson flotation cell is used and compared with current operating systems. In order to have an accurate comparison, a laboratory Denver cell is used in parallel. Under optimal circumstances for flotation of NaCl using Jameson cell recovery of 89.48% and grade of 83.24% are obtained. Concentration of Armoflote 619 as appropriate collector for NaCl flotation in optimum condition was 150 gr/ton and S/L ratio of 20% obtained as the best solid content. In the same situations in Denver cell 85.18% recovery for sodium Chloride with concentrate grade of 68.34% achieved as well.

It is a short report about the synthesis of complex shaped (sperm-like and ribbon-like) gold nanoparticles that have been achieved by using bottom up chemical synthesis technique. These methods are not only simple in approach, but it gives some new irregular shapes of gold nanoparticles. Sperm-like particle are showing some sharp edges, rounded, and twist/ turns within a single nanostructure. Instead of their irregular structure, such particles have been observed self- assembled in the best possible sterically orientations. Similarly, ribbon-like nanostructures are showing analogous UV-vis peaks like nano rods, but their structure seems to be disrupted and shaped like a ribbon. Moreover, since these nanoparticles are comprising of twisted and sharp edges could be helpful in many applications associated with such complex building blocks.

Indiscriminate disposal of different kinds of wastes on soil at auto-repair sites in Makurdi, Nigeria is becoming an environmental issue and the restoration of impacted soil is a challenge. The potential of single surfactants and their binary blends to remove mixed contaminants were evaluated via bench scale soil washing experiments. Impacted soil samples from auto-repair site, located in Makurdi Nigeria was assayed for Cd, Cu, Ni, Pb, Zn and total petroleum hydrocarbon (TPH) concentrations. Batch and column soil washing experiments were designed to assess the effectiveness of the single surfactants (sodium dodecyl sulphate (SDS) and Triton x-100 or their binary blends to remove the mixed contaminants with the view to optimizing operating conditions such as surfactant initial concentration (10-150 mM), surfactant initial pH (3-12), soil/liquid ratio (1:50-1:1 g/mL), washing time (30-240 min) and % w/w of surfactant in blend. Prior to soil washing, the critical micelle concentration (CMC) of the surfactants were measured to be: SDS (8.50 mM) and Triton x-100 (0.25 mM. Results of batch soil washing experiments for the two surfactants showed that % contaminants removal increases as the initial surfactants concentration increases, decreases as pH increases, increases as S/L ratio decreases and increases as washing time increases. Results of column experiment showed that % contaminants removal decreases with time. Synergism parameter showed more synergistic effects in the binary blend and hence was more effective than the individual surfactants. Reasons for these behaviors have been suggested.

Here we studied total phosphorus and its fractions in sediments from the Cochin backwaters along with dissolved inorganic phosphate, tidal currents, pH, and salinity during the monsoon and pre-monsoon periods. During the monsoon, sediments function as a sink for phosphate derived from land-based pollutant sources, whereas, during the pre-monsoon, sediment re-suspension provides a source of phosphate to the overlying water column, both with the capacity to alter eutrophication events. The heavy river runoff during the monsoon lowers the pH and salinity of the water column, thereby enhancing adsorption of phosphorus from water to sediments. In contrast, seawater incursion during the pre-monsoon increases the pH and salinity of the water column to enhance the desorption of phosphorus from sediments to the water. Iron-bound inorganic (0.48-0.78 mg g^-1) and organic phosphorus (1.04-1.30 mg g^-1), calcium-bound inorganic (0.78-1.56 mg g^-1) and organic phosphorus (1.13-1.83 mg g^-1), acidsoluble organic phosphorus (0.07-0.21 mg g^-1), and alkali-soluble organic phosphorus (0.22-0.70 mg g^-1), were detected in sediments. The main sedimentary phosphorus pool was a calcium- and iron-bound phosphorus compound. Precipitation/flocculation of dissolved inorganic phosphate within the estuarine salinity gradients (~15-30), followed by its adsorption/desorption with iron oxy-hydroxides and calcium carbonate minerals that settle in the bottom sediments govern the phosphorus biogeochemistry of the Cochin backwaters.