فهرست مطالب ghasem kiani

Cyanide can be removed from aqueous solutions using different but expensive methods. In this study، Lewatit FO36 exchange resin was used to remove cyanide.

Removing cyanide from the aqueous solutions with the Lewatit FO36 exchange resin was studied via considering the effects of absorbent dose، initial cyanide concentration، contact time and pH in batch phase.

In the batch ion exchange process، it was observed that the pH of solution and the contact time of nano particle resin in acidic conditions were very influential in obtaining the maximum removal. The optimum time was reached after 60 minutes of contact. In 60-minute contact time، the removal efficiency decreased from 74% to 42% by increasing pH from 7 to 11. The results showed that at the resin dose of 3 gr/L، contact time of 60 minutes، pH of 7 and cyanide concentration of 2. 5 mg/L، the cyanide maximum removal efficiency reached 81%. Lewatit FO36 showed high bonding constant and the ion exchange of cyanide on the cation exchange resin followed first order reversible kinetics.

The cyanide removal efficiency was initially fast but slowed down later and the removal efficiency was higher at neutral and acidic pH. However، due to its regeneration characteristic، Lewatit FO36 resin can be used as a convenient option to reduce the level of cyanide from the industrial waste water and specifically electroplating industries، where the problem of cyanide in sewage is ubiquitous.

Untreated leachate is being discharged into the environment in many countries worldwide. Leachate treatment methods have not been unified so far due to the variable composition of leachate. Moreover، the lack of appropriate treatment and disposal of leachate causes environmental pollution. This study aimed to compare removal efficiency of chemical oxygen demand (COD) and total suspended solids (TSS) of leachate of the Isfahan compost plant using ferrous sulfate، ferric chloride and poly ferric sulfate، and identify the most convenient coagulant and co-coagulant.

This experimental study was conducted to investigate the COD and TSS removal from leachate of the Isfahan compost plant using different coagulants and co-coagulants. Different concentrations and pH levels for each of the coagulants were tested and the most convenient coagulant was identified. This experiment was conducted using the Jar test method. TSS and COD levels were measured by standard methods of B-5210 and D-2540 respectively.

According to the results، pH level of 10، ferrous sulfate with the dose of 2 g/L and 2. 5 g/L resulted in maximum removal efficiency of 43% for COD and 38% for TSS. In pH = 10، ferric chloride with dose of 1. 5 g/L and 2 g/L resulted in maximum removal efficiency of 31% for COD and 47% for TSS respectively. In pH = 11، poly ferric sulfate with the dose of 2 g/L and 2. 5 g/L resulted in maximum removal efficiency of 49% for COD and 51% for TSS respectively. The most convenient co-coagulant for ferric chloride and poly ferric sulfate was SNF-AN913 that resulted in 41% and 58% COD removal، respectively. Concerning ferrous sulfate، the preastol co-coagulant with 51% COD removal had the highest removal efficiency.

The best coagulant for COD and TSS removal was poly ferric sulfate which contributed to better results with an alkaline pH. According to obtained data flocculation and coagulation can be used as convenient، inexpensive pretreatment methods to treat leachate of the Isfahan compost plant، and process the leachate for a better and more convenient treatment using other methods.

Solid waste management includes 8 stages including source reduction, production, storage, collection, transportation, recycling, disposal and monitoring after disposal. Production stage has a critical role on solid waste management process. Since people are the first ring of this chain, their awareness and proper attitude can lead to more accurate and more efficient performance of the system.

This was a descriptive, analytical survey performed with a cross-sectional approach. The study population included 90 people from an area called "Ramshe" in Isfahan. Subjects were questioned by a questionnaire. SPSS11.5 was used for data analysis.

The mean awareness was 8.05 ± 1.2 (out of 14) that was evaluated as higher than moderate. The mean attitude was 2.52 ± 2.3 (zero represented indifference) that shows the attitude of people was positive. 38.5% and 33.7% of respondents respectively introduced sanitary landfills and recycling as the best method for waste disposal. In addition, 64% of people believed that waste collection should be done twice a week. Furthermore, 38.3% believed that waste collection should be done between 7-9 a.m. While 32.3% of respondents partially disagreed with selling the waste to vendors, 29.3% were completely against it.

According to the findings of this survey, there was a significant relationship between awareness and job and education level. Due to a satisfactory level of awareness about the topic of the survey, influential factors on people's low performance should be evaluated. An appropriate plan to improve the performance should also be devised. A suitable and practical recycle plan with a maximum public participation seems to be very beneficial to improve solid waste management.