جستجوی مقالات مرتبط با کلیدواژه "waste water" در نشریات گروه "شیمی"

Water contamination by various pollutants, such as conventional pollutants like dyes and other emerging micropollutants, is of great concern. Nowadays, there are a host of processes for the removal of dyes from contaminated water. Due to its greater surface area, mechanical properties, and thermal properties, PANI got wide acceptance. It is prepared by chemical, electrochemical, or photochemical polymerizations. Smart properties of PANI are further enhanced by adding dopants which may be inorganic or organic, like HCl, H2SO4, and nicotinic acid. Due to π conjugated electrons, PANI nanocomposites photo-catalytically degrade dye components from wastewater. However, adsorption is the most efficient and promising one. These composites become good hosts to adsorb dye components on their surface by cationic π-interaction or anionic π- interaction. The unique doping and dedoping properties of PANI change its morphology, pore size, and surface charge, enhancing the adsorbate-adsorbent interactions and the adsorption performance. The adsorption mechanism of dye on the surface of the PANI nanocomposite involves H-bonding, van der Walls interactions, covalent interactions, and electrostatic interactions. In the end, future perspectives on removing dyes using PANI are discussed.

A new method is proposed to detect and precisely determining of promethazine HCl. This procedure is easy, straightforward, quick, and cost-effective technique. It is applicable to a wide range of samples, environmental, municipal wastewater, and of course, pharmaceutical preparations (for both tablets and injections). The highest absorbance value was obtained at 248 nm of a uniform content in distilled water. This procedure obeys Beer-Lambert low at a range of 0.5-15 µg/mL, while the registered molar absorptivity is 2.8X104 L.mol-1.cm-1, whereas the relative standard deviation is less than 2%, and the accuracy (average recovery%) is 100 ± 0.9. This technique was substantiated by sensitivity and precision which confirms appropriation for regular analysis of promethazine HCl in actual samples.

Water chemical pollution originates from a wide range of toxic derivatives, especially heavy metals and dyes. Its destructive effects on humans and the ecosystem have been considered as a serious environmental disaster. Therefore, there is a need to develop technologies to remove toxic pollutants from the environment. Adsorption is one of the most common methods of removing contaminants from wastewater among all the proposed methods. Adsorption is an optional method for industrial sewage treatment and a useful instrument for environmental protection. In recent years, numerous studies have been conducted to achieve low-cost, efficient, and environmentally friendly adsorbents. Among the low-cost adsorbents, the application of agricultural waste, as bio-adsorbent, is the most widely used for removing heavy metals and dyes. The advantages of using these compounds are low cost, good efficiency, minimal energy, simple maintenance and high adsorption capacity. This study deals with the risks, effects, and resources of manufacturers of heavy metal and dyes in addition to examination of agricultural wastes as low-cost adsorbents. Moreover, equilibrium, kinetic, and thermodynamic behaviors of the process of adsorption of heavy metal ions and dyes, using Langmuir and Freundlich adsorption isotherms, and Pseudo first and second-order kinetic models, and thermodynamic parameters were studied.

A method for treating fuel oil and waste water of power plant is suggested which is including vanadium elimination through contacting with humic acid coated magnetic nano-adsorbent. The nano-adsorbent was modified with humic acid (HA) as a compound having carboxyl, hydroxyl and amin functional groups. HA/Fe3O4 nanoparticles were prepared by a co-precipitation procedure and were characterized using different techniques such as dynamic light scattering (DLS), Transmission electron microscopy (TEM), FTIR spectroscopy, X-ray diffraction spectroscopy. The surface charge of the nano-adsorbents was determined by Zeta potential technique and their magnetic properties were investigated by vibrational sample magnetometer (VSM). It was observed that the synthesized nanoparticles have a mean diameter about 14 nm. The effects of several experimental factors such as pH, adsorbent dosage, contact time and initial vanadium concentration, on the nano-adsorbent ability for vanadium removal were investigated. The best results were obtained using 10 mg/ml of nanoparticles at pH 5 and contact time 30 min. At this condition about 99.5 % of V(IV) could be removed from synthetic samples. Maximum adsorption capacity for vanadium (IV) was 8.97 mg/g which was fitted to Langmuir isotherm model. The ability of HA/Fe3O4 for the vanadium removal from fuel oil and wastewater of power plant was also investigated. It was observed that more than 93% of vanadium content could be removed from waste water and 67% form fuel oil using proposed nano-adsorbent.

The focus of this work is on the preparation of a Cu2 all-solid-state ion selective electrode (ASS-ISE) to be used in the analysis of copper ions in complex samples. The ASSISE was composed of a conductive substrate of graphite-epoxy resin on a copper wire. This conductive substrate was further coated with a layer of Cu2+selective PVC membrane, comprising 32% of PVC, 57% of nitrobenzene (NB) as the plasticizing solvent, 2% of an ionic additive (i.e. sodium tetraphenyl borate (NaTPB)), and 9% of an organic ligand named 3-(2-methyl-2,3-dihydrobenzothiazol-2-yl)-2H-chromen-2-one (L) as the selective ionophore. The device with the optimal composition had a Nernstian response of 29.3±0.3 mV/decade from 1.0×10-8 M to 1.0×10-3 M of the analyte and its lower detection limit was estimated at be 4.0×10-9 M. The ASS-ISE showed excellent selectivity for the target ion in the presence of various common interfering ions, and was found to be satisfactorily applicable to the analysis of copper electroplating waste water samples.

Zeolites are widely used in wastewater and contaminated water refinement due to their great adsorption properties. However, Clinoptilolite (as one type of Zeolites) has a relatively low adsorption capacity at least for arsenic ions. Therefore, in order to increase the adsorption capacity, natural Clinoptilolite was modified with sulfuric acid and various tests were then conducted to determine the best conditions for obtaining the maximum capacity of adsorption. The results showed that parameters such as arsenic initial concentration, adsorbent's particles size, adsorbent dosage and solution pH affect the adsorption capacity. Arsenic maximum adsorption was obtained at pH 8. Furthermore, the maximum adsorption capacity was found to be in an adsorbent modified with 1 M acid. The contact time or the time of balance between the adsorbent and analyte was determined to be 240 min and the optimal amount of Zeolite to obtain was determined to be 480 g/L. The rate of arsenic removal under the optimal conditions is 27.69%. The modified Clinoptilolite capacity for arsenic adsorption increased with reducing the adsorbent particles size to 0.5 mm. Besides, among the three examined isotherms including the Langmuir, Freundlich and Dubinin-Radushkevich isotherms, the Langmuir and Freundlich models well described arsenic adsorption. Considering the more favorable adsorption efficiency of Clinoptilolite modified with sulfuric acid compared to natural Clinoptilolite, the modified one can be proposed as an appropriate and inexpensive adsorbent for arsenic removal in waste water refinement.

An all-solid-state ion selective electrode (ASS-ISE) has been developed and used for the selective determination of Cu(II) in the presence of interfering species in complex samples. The device is composed of a conductive graphite-epoxy resin composite coated on a copper wire to act as the ASS, which is further coated with a Cu(II) selective PVC membrane, containing 30% PVC, 60% 0-nitrophenyloctyl ether (NPOE), 3% of sodium tetraphenyl borate, and 7% of 2-(1՛-(4՛-(1՛՛-Hydroxy-2՛՛-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol as the selective ion-carrier (L). The behavior of the device revealed that it has a Nernstian response of 29.7±0.2 mV/decade over a rather wide concentration range from 1.0×10-8 M to 1.0×10-3 M and the ASS-ISE could be used down to detection limits as low as 5.5×10-9 M. Further evaluations of the electrode proved it to have a good selectivity for Cu(II) as opposed to different commonly occurring interfering ions. The applicability of the ASS-ISE to the analysis Cu(II) concentration in copper electroplating waste water samples with complex matrices was also evaluated and found to be viable.