Application of nano-electrode platinum [Pt] and nano-wire titanium [Ti] for increasing electrical energy generation in microbial fuel cells of synthetic wastewater with carbon source [Acetate]

The microbial fuel cells [MFCs] are a kind of systems through which the anaerobic bacteria along with the oxidation of simple or complicated organic matter in the wastewater can generate the electric power. This is a modern approach used in generation of the clean and renewable energy. In this research, two pilot laboratories of double-chamber microbial fuel cells were made. One of them contained platinum electrode and simple nano-wire Titanium and the other had nano-electrode Platinum and nano-wire with equal volume of 1 liter. They were launched in 4 Hydraulic Retention Time [2.5, 3.5, 4.5 and 5.5 hrs.] and increased in 4 steps of organic loading rate with synthetic wastewater with carbon source [acetate] and temperature [20 +/- 5°C]. The voltage and electric current was measured by means of digital multimetre. The performance of the two reactors in generation of electricity was investigated based on the polarization curve. Maximum voltage and current output were, respectively, 1425 mV and 13.1 mA, and the maximum power density and current density were, respectively 78 mW/nr and 67.3 mA/m[2] and columbic efficiency were achieved in 34.6% in reactor with nano-electrode Platinum and nano-wire Titanium [in HRT 4.5 hr and external resistance was 10[KT]. In addition, the maximum removal rate of COD in organic loading rate 3.99 Kg COD/m day is equal to 98.28% for nano-electric and nano-wire and 72.5% for simple electrode and wire

Chemical partitioning and pollution intensity of heavy metals in siahrud river sediment

In the recent years, sediments are used for the assessment of pollution. Since sediments have been in contact for a long time with over lying water, therefore they have been able to absorb pollution on to their surface. In the present investigation, the surficial sediments of Siahrud River have been analyzed. Grab samples were taken from ten samplings sites. The samples were immediately sealed and stored at 4°C until their arrival at the laboratory. Grain size fraction less than 63 micro m was chosen for chemical analysis. The total metal content was determined by digesting the samples with a mixture of HNO[3] and HClO[4]. The chemical partitioning of metals was determined by means of the sequential extraction scheme proposed by the European Union's Standards, Measurements and Testing Program [SM and T, formerly BCR]. This scheme consists of three successive extractions that make it possible to determine the association of the metals in three phases: acid-soluble, reducible and oxidizable. The most resistant bonds were digested by hot 50% HCl [phase 4]. Furthermore, a fourth fifth phase, within lattice was determined as the difference between the total metal content and the sum of the contents in the four previous phases. The analysis of metals in the solutions was carried out by an inductively coupled plasma mass spectrometer [ICPAES]. The accuracy of the analytical procedures for total metal determinations was checked using CRM 320 [sediment reference material]. Replicate analysis of this CRM showed good accuracy, with recovery rates for metals between 97 and 101%. A standard reference material [CRM-60l] was used to verify the accuracy of the sequential extraction method. Similarities between the behavior and origin of the metals studied were established by cluster analysis using the weighted pair group method. The loose, sulphide and organic bonds of metals with various sedimentary phases has been assessed by chemical partitioning technique. The sum of these three bonds is indicative of anthropogenic source of metals into the river. The lithogenic portion of metals was obtained by a two step chemical partitioning technique. The anthropogenic portion of metal contents in river sediments shows the following pattern: Pb[85%]>Zn[84%]>Cd[62%]>As[47%]>Mn[35%]>Ni[34%]>Cu[21%] The results show that bio-availability of metals such as Cd, Zn and as are highly dependent on anthropogenic portion and especially loosely bonded ions of such metals. The overall pollution intensity was obtained by various pollution intensity indices. The pollution intensity of Zn and Pb in the sediments of Siahrud River is 3.572 and 3.148, respectively that are indicative of high pollution intensity

Preozonation and prechlorination effects on TOC removal by nanofiltration in water treatment

In this study, NF membrane was used for surface water treatment. The rejection of organic material, measured as Total organic carbon [TOC], by Nanofiltration was examined. The effects of application of pre-ozonation and pre-chlorination on TOC removal are discussed and their performances are compared with the performances of Nanofiltraion system without pretreatment process. In NF, natural organic rejection is high and no pre-treatment are required. Coagulation targets large hydrophobic organics which foul NF membranes by precipitation and gel layer formation. The results showed that TOC removal in Preozonation-coagulation was higher than prechlorination-Coagulation. In addition pretreatment increases Nanofiltration efficiency

Environmental geochemistry of heavy metals in a sediment core of Bushehr, Persian gulf

In present study, the geochemistry of a sediment core from the Persian Gulf is investigated. The sources of trace elements [Cu, Zn, Pb, Ni, Cr, Mn] have been investigated by the method of cluster analysis as well as chemical partitioning techniques. Cluster analysis shows that Pb, Cu, Cr and Zn are originated from oil pollution sources taking into account Zn as an oil pollution indicator. Higher concentrations of Mn at depth of 7cm clearly shows the movement of Mn from the lower layer of the sediment core. Considerable amount of Mn, Pb and Cu are found in lithogenous portion The results of partition studies has revealed the percentile of anthropogenic portion of metals as: Mn [46%]> pb [40%]> Cu [18%]> Zn [12.8%]> Fe [2.4%]> Cr and Ni [0.03] Finally, the concentration of studied metals are compared with those of mean crust and mean world sediments. Though concentrations of a few metals are higher than mean crust and men world sediments but Cr in-spite of its higher concentration is mainly derived from natural resources. The results indicate that, a system that combines the two mentioned processes not only shortens stabilization time, but also improves the products quality. Combining the two systems resulted in a product that was more stable and homogenous; the product could meet the pathogen reduction requirements