R Fouladi Fard, A.a Ebrahimi,
Volume 3, Issue 4 (8 2011)
Abstract
Background and Objective: Nickel (II) and cadmium (II) are important in environmental pollutant. Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions because of the decrease in sludge problems, economical issues, high efficiency and compatibility with the environment.
Materials and Methods: power of wasted activated sludge have been contact with nickel (II) and cadmium (II) solutions in 0.25 and 0.75 milli molar invarious pHs and mixing pace, at 24-26 0C temperature on batch reactor system .After two hours (continuously 5-420 min in kinetic study) samples were analyzed with atomic absorption spectrophotometer.
Results:The kinetic study results show that equilibrium adsorption time for nickel (II) and cadmium
(II) reached within 2 hr, but the profile curve of cadmium (II) biosorption was smoother than nickel (II) biosorption. Both metals adsorption followed the Langmuir model and the maximum adsorption capacity (qmax) for nickel (II) and cadmium (II) was 0.195 and 0.37 milli mole per gram respectively. The increase in pH resulted in adsorption increase for both metals. For cadmium (II) at 0.25 and 0.75 mMinitial concentration there was no adsorption at pH 2 where as nickel (0.25 mM) adsorption was observed at the same pH. The optimum mixing rate for both metals was 200 rpm and this effect was more obviously in greater concentration.
Conclusion: Like othe biosorbents ,wasted activated sludge showed greater capacity for cadmium(II) biosorption than nickel (II). Cadmium (II) in modeling and biosorption characteristics study had more conformity than nickel (II).
Faezeh Kamal, Reza Fouladi Fard, Azam Sabahi Hoveida, Zabihollah Gharlipour, Nayereh Rezaie Rahimi,
Volume 14, Issue 2 (9-2021)
Abstract
Background and Objective: The most important first step in promoting environmental performance is identifying and evaluating environmental behavior. In this regard the measuring tool is considered an environmental behavior questionnaire. Validity and reliability of the questionnaire before its application is essential. Thus this research was conducted with the aim of assessing the validity and reliability of questionnaires.
Materials and Methods: The environmental behavior questionnaire containing 36 questions was designed using the literature review and expert panel opinions. Then, the validity of the questionnaire was assessed by content validity index (CVI) and content validity ratio (CVR) and its reliability was evaluated using Cronbach's alpha coefficient by 14 experts and 40 target groups. Finally, data were analyzed by SPSS 20 software.
Results: The results showed that the questionnaire with 36 items had CVI and CVR of 0.896 and 0.726, respectively, and 4 items should be excluded from the questionnaire due to non-compliance with content validity indices. The questionnaire exhibited high internal consistency and hence was acceptable owing to the Cronbach's alpha coefficient of 0.85.
Conclusion: The questionnaire was designed to evaluate environmental performance of citizens and can be cited in future studies.
