مدلسازی و تعیین شرایط بهینه حذف نیکل از محلول‌های آبی با بیوچار اصلاح شده با عصاره پوست گردو

در دﻫﻪﻫﺎی اﺧﯿﺮ، آﻟﻮدﮔﯽ ﻣﻨﺎﺑﻊ آب ﺑﻪ آﻻﯾﻨﺪهﻫﺎی ﻏﯿﺮآﻟﯽ، ﯾﮑﯽ از ﻣﻬﻤﺘﺮﯾﻦ ﭼﺎﻟﺶﻫﺎی زﯾﺴﺖ ﻣﺤﯿﻄﯽ ﻣﻬﻢ ﺟﻮاﻣﻊ ﺑﺸﺮی ﻣﻄﺮح ﻣﯽﺷﻮد ﮐﻪ ﻟﺰوم ﭘﺎﮐﺴﺎزی آن ﺑﻪ روشﻫﺎی ارزان ﻗﯿﻤﺖ و دوﺳﺘﺪار ﻣﺤﯿﻂ زﯾﺴﺖ را ﻃﻠﺐ ﻣﯽﮐﻨﺪ. در ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ، ﺑﯿﻮﭼﺎر ﺧﺎم ﻣﯿﻮه ﺳﺮو ﺗﺤﺖ ﻓﺮاﯾﻨﺪ اﺻﻼح ﺷﯿﻤﯿﺎﯾﯽ، ﺑﺎ اﺳﺘﻔﺎده از ﻋﺼﺎره ﭘﻮﺳﺖ ﮔﺮدو اﺻﻼح ﮔﺮدﯾﺪ و ﺑﻬﯿﻨﻪ ﺳﺎزی ﻋﻤﻠﮑﺮد آن ﺑﺮ ﺣﺬف ﻧﯿﮑﻞ در ﻣﺤﻠﻮلﻫﺎی آﺑﯽ، ﻣﺘﺎﺛﺮ از ﻓﺎﮐﺘﻮرﻫﺎی ﻣﺨﺘﻠﻒ )ﻏﻠﻈﺖ اوﻟﯿﻪ ﻧﯿﮑﻞ، ph ﻣﺤﻠﻮل، ﻣﯿﺰان ﺟﺎذب و زﻣﺎن ﺗﻤﺎس( ﺑﺎ اﺳﺘﻔﺎده از روش ﺳﻄﺢ ﭘﺎﺳﺦ، ﻣﻮرد ارزﯾﺎﺑﯽ ﻗﺮار ﮔﺮﻓﺖ. ﺑﺮﺧﻼف اﻧﺘﻈﺎر، اﺻﻼح ﺷﯿﻤﯿﺎﯾﯽ ﺳﺒﺐ ﮐﺎﻫﺶ ﺳﻄﺢ وﯾﮋه و ﮐﺎﻫﺶ ﮔﺮوهﻫﺎی ﻋﺎﻣﻞ ﻣﻮﺛﺮ در ﺣﺬف ﻧﯿﮑﻞ )ﮔﺮوهﻫﺎی ﻋﺎﻣﻞ ﺣﺎوی اﮐﺴﯿﮋن دار و c-c( در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻧﻤﻮﻧﻪ ﺑﯿﻮﭼﺎر ﻏﯿﺮ اﺻﻼﺣﯽ ﺷﺪ. ﺑﺮرﺳﯽﻫﺎی اﻧﺠﺎم ﺷﺪه از ﺣﺬف ﻧﯿﮑﻞ ﺗﻮﺳﻂ ﺑﯿﻮﭼﺎر اﺻﻼح ﺷﺪه ﻧﯿﺰ ﻧﺸﺎن از ﮐﺎﻫﺶ ﻣﻌﻨﯽ دار ﺣﺬف ﻧﯿﮑﻞ ﺗﻮﺳﻂ اﯾﻦ ﺟﺎذب در ﺷﺮاﯾﻂ ﯾﮑﺴﺎن در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻧﻤﻮﻧﻪ ﻏﯿﺮ اﺻﻼﺣﯽ داﺷﺖ، ﺑﻪ ﻧﺤﻮی ﮐﻪ ﻣﯿﺰان ﻣﺘﻮﺳﻂ ﺣﺬف ﻧﯿﮑﻞ در ﺷﺮاﯾﻂ ﻣﺸﺎﺑﻪ در ﺟﺎذب ﻏﯿﺮ اﺻﻼﺣﯽ، 1/8 ﺑﺮاﺑﺮ ﺑﯿﺸﺘﺮ از ﺟﺎذب اﺻﻼح ﺷﺪه ﺑﻮد. ﺑﺮرﺳﯽ ﻓﺎﮐﺘﻮرﻫﺎی ﻣﻮﺛﺮ ﺑﺮ ﺣﺬف ﻧﯿﮑﻞ در دو ﺟﺎذب اﺻﻼح ﺷﺪه و ﻏﯿﺮ اﺻﻼح ﺷﺪه ﻧﺸﺎن داد ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻏﻠﻈﺖ اوﻟﯿﻪ ﻧﯿﮑﻞ، ﺣﺬف ﻧﯿﮑﻞ روﻧﺪ ﮐﺎﻫﺸﯽ داﺷﺖ؛ در ﺣﺎﻟﯽ ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻣﻘﺎدﯾﺮ ﺳﺎﯾﺮ ﻓﺎﮐﺘﻮرﻫﺎ، ﺣﺬف ﻧﯿﮑﻞ روﻧﺪ ﻧﺴﺒﺘﺎ اﻓﺰاﯾﺸﯽ را ﻧﺸﺎن داد. ﺑﺮازش دادهﻫﺎی ﺑﺪﺳﺖ آﻣﺪه از ﺣﺬف ﻧﯿﮑﻞ ﺗﻮﺳﻂ ﻫﺮ دو ﺟﺎذب ﺑﺮ روش ﺳﻄﺢ ﭘﺎﺳﺦ، ﻧﺸﺎن از ﭘﯿﺶ ﺑﯿﻨﯽ ﻣﻨﺎﺳﺐ ﻣﺪل ﺑﺎﮐﺲ-ﺑﻨﮑﻦ در ﺑﻬﯿﻨﻪ ﺳﺎزی ﺣﺬف ﻧﯿﮑﻞ از ﻣﺤﻠﻮلﻫﺎی آﺑﯽ داﺷﺖ. ﻧﺘﺎﯾﺞ ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﻧﺸﺎن ﻣﯽدﻫﺪ، اﺻﻼح و ﻣﻬﻨﺪﺳﯽ ﺑﯿﻮﭼﺎرﻫﺎ ﺑﻪ روش ﺷﯿﻤﯿﺎﯾﯽ ذﮐﺮ ﺷﺪه، ﺑﺎ ﺗﺎﺛﯿﺮ ﺑﺮ ﮐﺎﻫﺶ ﺟﺬب ﻓﯿﺰﯾﮑﯽ )ﮐﺎﻫﺶ ﺳﻄﺢ وﯾﮋه( و ﺷﯿﻤﯿﺎﯾﯽ )ﮐﺎﻫﺶ ﺷﺪت ﮔﺮوهﻫﺎی ﻋﺎﻣﻞ ﻣﻮﺛﺮ ﺑﺮ ﺟﺬب(، ﺳﺒﺐ ﮐﺎﻫﺶ راﻧﺪﻣﺎن ﺣﺬف ﻧﯿﮑﻞ در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻧﻤﻮﻧﻪ ﺧﺎم ﺑﯿﻮﭼﺎر ﺷﺪه اﺳﺖ، ﮐﻪ ﻓﺮﺿﯿﻪ اﻓﺰاﯾﺶ ﻫﻤﯿﺸﮕﯽ ﮐﺎراﯾﯽ ﺣﺬف ﻓﻠﺰات ﺳﻨﮕﯿﻦ ﺑﺎ اﺻﻼح ﺷﯿﻤﯿﺎﯾﯽ ﺑﯿﻮﭼﺎر را ﺑﻪ ﭼﺎﻟﺶ ﻣﯽﮐﺸﺪ.

modeling and determination of optimal conditions for nickel removal from aqueous solutions using walnut peel extract-modified biochar

in recent decades, the contamination of water resources with inorganic pollutants has become one of the most important environmental challenges of human societies, which requires the need to clean it in cost-effective and eco-friendly remediation strategies. this study evaluated the performance optimization of cypress cone raw biochar modified with walnut peel extract for ni removal in aqueous solutions. the chemical modification process was employed, and the effects of various factors (initial ni concentration, solution ph, adsorbent amount, and contact time) were assessed using response surface methodology (rsm). contrary to expectation, chemical modification caused a decrease in the specific surface area and a decrease in effective functional groups in ni removal (functional groups containing oxygen and c-c) compared to the non-modified biochar sample. the investigations of ni removal by modified biochar also showed a significant reduction of ni removal by this adsorbent in the same conditions compared to the non-amended sample, so that the average amount of ni removal in the same conditions in the non-modified adsorbent was 1.8 times more than modified biochar. the investigation of the factors affecting the removal of ni in two modified and non-modified adsorbents showed that with the increase of the initial concentration of ni, the removal of ni had a decreasing trend; while with the increase of other factors, ni removal showed a relatively increasing trend. fitting the data obtained from the removal of ni by both adsorbents on rsm showed the appropriate prediction of the box-benken model in the optimization of ni removal from aqueous solutions. the results of the present study show that the modification and engineering of biochars by the mentioned chemical method, with the effect of reducing the physical adsorption (reduction of the specific surface area) and chemical adsorption (reduction of the intensity of the active groups affecting the adsorption), caused the reduction of ni removal efficiency compared to the raw sample, which challenges the hypothesis of constant increase of heavy metal removal efficiency by chemical modification of biochar.