Các công trình đã thực hiện, Chưa được phân loại, Style, TIN TỨC, Uncategorized
NƯỚC CỨNG VÀ TÁC HẠI CỦA NƯỚC CỨNG
Chỉ số pH liên quan đến độ cứng và độ kềm của nước. Khi độ cứng và độ kềm ổn định, độ pH ít thay đổi. Nước tự nhiên chứa trên 3 mini đương lượng gam cation canxi (Ca2+) và magie (Mg2+) trong một lít. Nước nhiều Mg2+ có vị đắng. Tổng hàm lượng ion Ca2+ và Mg2+ đặc trưng cho tính chất cứng của nước. Ngày nay, người ta còn tính cả ion Fe2+ và Na+ vào độ cứng. Độ cứng của nước thiên nhiên dao động rất nhiều và đặc trưng lớn ở nước ngầm.
Vôi cứng tạo mảng bám trên bề mặt làm hỏng các thiết bị chứa nước
1. Độ cứng của nước
Độ cứng của nước được quyết định bởi hàm lượng chất khoáng hòa tan trong nước, chủ yếu là do các muối có chứa ion Ca++ và Mg++. Độ cứng của nước được chia làm 2 loại:
Độ cứng tạm thời hay độ cứng carbonat: Tạo bởi các muối Ca và Mg carbonat và bicarbonat, trong đó chủ yếu là bicarbonat vì muối carbobat Ca và Mg hầu như không tan trong nước. Gọi là độ cứng tạm thời vì chúng ta có thể giảm được nó bằng nhiều phương pháp đơn giản. Trong tự nhiên, độ cứng tạm thời của nước cũng thay đổi thường xuyên dưới tác dụng của nhiều yếu tố, ví dụ như nhiệt độ …
Độ cứng vĩnh viễn: Tạo bởi các muối khác của Ca và Mg như sulphat, clorua… chỉ có thể thay đổi bằng các phương pháp phức tạp và đắt tiền.
Thông thường người ta chỉ quan tâm đến độ cứng tạm thời của nước vì nó có ảnh hưởng nhiều hơn là độ cứng vĩnh viễn. Có nhiều đơn vị đo độ cứng khác nhau, nhưng chủ yếu người ta dùng 3 đơn vị đo: độ dH, mg đương lượng/lít và ppm. Để đơn giản, khi đo độ cứng người ta thường quy về 1 loại muối là CaCO3.
Nước có độ cứng tạm thời lớn hơn 100 ppm được coi là nước cứng, dưới mức đó được coi là nước mềm.
2. Tác hại của nước cứng
Độ cứng vĩnh viễn của nước ít ảnh hưởng đến sinh vật trừ phi nó quá cao, ngược lại, độ cứng tạm thời lại có ảnh hưởng rất lớn. Nguyên nhân là vì thành phần chính tạo ra độ cứng tạm thời là các muối bicarbonat Ca và Mg: Ca(HCO3)2 và Mg(HCO3)2, chúng là các muối hòa tan hoàn toàn nhưng không ổn định, không bền. Chúng dễ dàng bị phân hủy thành CaCO3, MgCO3 là các muối kết tủa:
Ca(HCO3)2 => CaCO3 + H2O + CO2
Mg(HCO3)2 => MgCO3 + H2O + CO2
Khi phản ứng phân hủy xảy ra trong cơ thể sinh vật, các muối này kết tủa trong cơ thể sinh vật sẽ gây hại không nhỏ. Ở con người, chúng là nguyên nhân gây ra sỏi thận và một trong các nguyên nhân gây tắc động mạch do đóng cặn vôi ở thành trong của động mạch. Lưu ý là các muối CaCO3 và MgCO3 là các muối kết tủa và chúng không thấm qua niêm mạc hệ tiêu hóa của chúng ta được, chỉ các muối hòa tan mới thấm được thôi. Vì vậy nước cứng chỉ có tác hại do các muối bicarbonat.
3. Các phương pháp làm mềm nước
Có rất nhiều phương pháp làm giảm độ cứng của nước, từ đơn giản đến phức tạp.
a. Làm nóng nước
Đun nóng nuớc sẽ làm giảm đáng kể độ cứng của nước
b. Làm nước lưu động liên tục
Khuấy liên tục hoặc bơm tuần hoàn liên tục cũng có tác dụng, tuy rằng khá chậm và trong nhiều trường hợp, sự phân hủy bicarbonat chậm hơn sự hòa tan bicarbonat mới từ các nguồn khác vào nước
c. Chưng cất nước
Về nguyên tắc, nước cất có thể coi là H2O tinh khiết hoàn toàn.
d. Lọc RO (Thẩm thấu ngược)
Công nghệ lọc RO cho phép loại bỏ gần như tất cả các chất hòa tan và không hòa tan ra khỏi nước, nước lọc RO có thể coi là H2O tinh khiết (tuy không bằng nước cất)
e. Trao đổi ion bằng sử dụng máy làm mềm nước
Đây là phương pháp được dùng phổ biến nhất vì có giá thành rẻ kể cả chi phí đầu tư lẫn chi phí vận hành. Nguyên lý của nó là đưa nước qua 1 vật liệu chứa các ion dương hoạt động mạnh hơn Ca++ và Mg++, vật liệu này sẽ hấp thụ các ion Ca++ và Mg++ trong nước và nhả ra các ion mạnh hơn kia, do đó tạo ra các hợp chất carbonat không kết tủa. Vật liệu đó được gọi là Cationit (hay cation-exchange resyn). Thông thường người ta dùng 2 loại cationit là Na-Cationit và H-Cationit tương ứng với các ion là Na+ và H+ và các hợp chất tạo ra tương ứng là Na2CO3 và H2CO3 (H2CO3 sẽ bị phân tích ngay thành H20 và CO2)
Khi các Cationit đã hết khả năng trao đổi, người ta phải “hoàn nguyên” tức là phục hồi lại các ion dương cho nó. Đối với Na-Cationit người ta dùng muối ăn NaCl, đối với H-Cationit người ta dùng axit.
Thiết bị trao đổi Na-Cationit thông thường có thể hạ độ cứng của nước xuống đến dưới 10 ppm, nếu được thiết kế đặc biệt có thể hạ xuống dưới 2 ppm. Mỗi lít hạt Na-Cationit có khả năng trao đổi khoảng từ 2-6 gam đương lượng tùy loại, tức là có thể làm hạ độ cứng từ 300 đến 1000 lít nước có độ cứng 6 mgdl/lít (300 ppm hay 16,8 dH) xuống 0 trước khi phải hoàn nguyên.
H-Cationit có khả năng trao đổi mạnh hơn Na-Cationit và cũng triệt để hơn vì nó loại bỏ hoàn toàn gốc carbonat ra khỏi nước. Tuy nhiên nó có giá thành cao hơn nhiều lần, chi phí vận hành cũng cao hơn (axit đắt hơn muối ăn) và yêu cầu vận hành cũng nghiêm ngặt hơn do phải dùng axit nên ít được sử dụng
Ngoài cách trao đổi ion dương người ta còn dùng cả trao đổi ion âm (chất trao đổi gọi là Anionit) để loại bỏ các ion HCO3- ra khỏi nước. Phương pháp này thường chỉ được sử dụng trong các nhà máy nhiệt điện, ở đó họ dùng cả Na-Cationit, H-Cationit và Anionit nối tiếp nhau trong 1 hệ thống.
Phương pháp trao đổi ion này được sử dụng rất rộng rãi và là phương pháp cơ bản để làm mềm nước trong công nghiêp. Kể cả đối với các thiết bị RO, để tăng tuổi thọ và giảm tải lên các thiết bị RO, người ta cũng làm mềm nước bằng trao đổi ion trước khi đưa nước vào lọc RO.
Pingback: Bỏ túi cách vệ sinh đường ống nước tại nhà hiệu quả
Thank you a lot for providing individuals with an extraordinarily spectacular opportunity to read critical reviews from here. It is often very pleasant and as well , stuffed with amusement for me personally and my office colleagues to search your site at minimum 3 times every week to read through the new things you will have. And indeed, I am just certainly happy with all the unique creative concepts you give. Selected 3 ideas in this post are essentially the simplest I have had.
I am just commenting to make you know of the brilliant encounter my cousin’s princess undergone reading through your site. She mastered a good number of details, not to mention what it’s like to possess a marvelous helping heart to get many people without problems thoroughly grasp certain specialized things. You truly exceeded visitors’ desires. Thanks for providing these priceless, safe, edifying and in addition cool guidance on the topic to Ethel.
Thanks so much for providing individuals with an extraordinarily wonderful opportunity to read from here. It really is so enjoyable and as well , packed with a good time for me personally and my office friends to visit your website on the least thrice per week to learn the latest secrets you will have. And lastly, I am certainly contented considering the cool concepts you serve. Selected 3 facts on this page are particularly the most impressive we have had.
Thanks a lot for providing individuals with such a marvellous opportunity to read critical reviews from this blog. It is often so great plus packed with a good time for me personally and my office co-workers to visit the blog at least thrice weekly to read the fresh secrets you have got. Of course, I’m also certainly motivated for the attractive tactics you give. Selected 4 points on this page are in reality the most efficient I’ve ever had.
I together with my buddies were analyzing the great suggestions from your web page and then unexpectedly got an awful suspicion I had not thanked the site owner for those tips. Those ladies ended up passionate to learn all of them and have in effect certainly been using them. Appreciate your being really kind and then for going for variety of quality information millions of individuals are really needing to discover. My personal sincere apologies for not expressing appreciation to sooner.
I and my buddies have already been looking at the great guidelines on your web blog and so then developed a terrible feeling I had not thanked the blog owner for those tips. All the young men were certainly happy to read them and have pretty much been having fun with these things. I appreciate you for simply being considerably helpful and also for using this kind of brilliant subject matter millions of individuals are really desirous to understand about. My personal honest apologies for not expressing appreciation to you earlier.
A lot of thanks for your own work on this site. Gloria enjoys getting into research and it’s easy to understand why. We notice all of the powerful way you present effective things on the website and therefore improve participation from some other people on the concept so our own girl is studying a whole lot. Have fun with the rest of the new year. You have been conducting a superb job.
I enjoy you because of your whole effort on this blog. My niece really likes getting into investigations and it’s easy to understand why. A lot of people learn all concerning the powerful mode you deliver reliable tricks via the web blog and even boost contribution from other ones on that situation and our favorite daughter is without a doubt being taught a lot of things. Take pleasure in the rest of the year. Your performing a remarkable job.
Thanks a lot for providing individuals with an extremely marvellous possiblity to read critical reviews from this web site. It can be very awesome and as well , jam-packed with a good time for me personally and my office co-workers to search your blog no less than thrice a week to learn the newest tips you will have. Of course, we are certainly satisfied with your stunning tactics served by you. Some 1 ideas in this posting are clearly the most effective we have all ever had.
I actually wanted to make a small comment to appreciate you for these lovely techniques you are posting at this website. My long internet search has finally been compensated with pleasant insight to write about with my partners. I ‘d mention that most of us website visitors actually are undoubtedly lucky to dwell in a magnificent place with very many brilliant individuals with valuable strategies. I feel rather blessed to have encountered your web page and look forward to many more enjoyable minutes reading here. Thanks a lot again for everything.
My spouse and i got contented when Raymond could round up his preliminary research while using the ideas he made in your site. It is now and again perplexing just to always be giving for free tips which often a number of people have been selling. And we do know we have the website owner to thank for that. All of the explanations you made, the simple site navigation, the relationships you will help to create – it’s got mostly extraordinary, and it’s really aiding our son and us reckon that this subject matter is interesting, and that’s particularly vital. Many thanks for all!
My wife and i have been absolutely excited Jordan managed to finish up his investigations while using the precious recommendations he received from your web page. It’s not at all simplistic just to continually be freely giving hints that many the others may have been selling. Therefore we keep in mind we need you to thank because of that. The specific explanations you’ve made, the easy website menu, the friendships your site assist to instill – it’s got mostly powerful, and it’s really helping our son in addition to our family understand the content is cool, and that’s extraordinarily mandatory. Thanks for all the pieces!
I really wanted to write down a small note in order to say thanks to you for the superb tips you are placing at this website. My prolonged internet lookup has finally been compensated with brilliant know-how to go over with my family and friends. I would declare that many of us website visitors are very fortunate to live in a superb website with very many special individuals with beneficial basics. I feel really fortunate to have encountered your entire web page and look forward to plenty of more fun times reading here. Thanks a lot again for everything.
I in addition to my buddies appeared to be checking out the great tips and hints found on the blog and so before long developed a horrible feeling I never expressed respect to the website owner for them. These boys became certainly thrilled to read through them and have surely been using those things. Appreciate your genuinely considerably thoughtful and then for figuring out this sort of helpful resources most people are really desirous to learn about. My honest regret for not expressing gratitude to you earlier.
I simply had to appreciate you again. I do not know what I could possibly have implemented without the actual pointers shown by you about such a subject matter. It had become a real frightening circumstance in my position, nevertheless observing the very specialised way you processed it forced me to jump for delight. Now i am grateful for your advice and then trust you realize what a great job you have been getting into teaching men and women using your web site. I know that you’ve never encountered all of us.
I wanted to draft you this little remark to finally say thank you over again regarding the breathtaking principles you have provided at this time. It was so tremendously generous with people like you to provide freely all that a number of us might have sold for an e-book to generate some cash for their own end, specifically seeing that you could possibly have done it in the event you desired. The pointers in addition served like a easy way to know that some people have the identical dreams really like my very own to find out significantly more when it comes to this problem. I’m sure there are thousands of more fun sessions up front for people who look over your site.
I must express thanks to the writer just for rescuing me from this type of circumstance. Right after browsing throughout the online world and obtaining recommendations that were not powerful, I thought my life was over. Existing devoid of the approaches to the problems you’ve solved by way of the article content is a crucial case, and the ones which could have in a wrong way damaged my career if I hadn’t encountered the website. The ability and kindness in taking care of a lot of stuff was useful. I am not sure what I would’ve done if I hadn’t encountered such a stuff like this. I can also now look ahead to my future. Thanks a lot very much for the professional and results-oriented guide. I will not hesitate to propose your site to any person who should have assistance about this topic.
I not to mention my buddies were found to be analyzing the nice tips on the website while instantly got a terrible suspicion I had not expressed respect to the web blog owner for them. My young men were definitely consequently excited to read through them and now have definitely been making the most of those things. Thank you for turning out to be very kind and also for pick out this form of extraordinary areas millions of individuals are really desirous to be informed on. My very own sincere regret for not expressing appreciation to earlier.
I actually wanted to write a brief word to be able to say thanks to you for those magnificent tips and tricks you are placing here. My extensive internet lookup has at the end of the day been rewarded with reasonable ideas to exchange with my great friends. I ‘d declare that many of us site visitors are rather lucky to dwell in a fantastic place with very many perfect individuals with very helpful tactics. I feel extremely fortunate to have encountered your entire website page and look forward to so many more fabulous times reading here. Thank you once more for everything.
I intended to send you the little word to be able to say thank you again on your spectacular tricks you have shared above. It was quite shockingly open-handed of you to make freely just what a few individuals would have distributed as an e book to earn some dough for their own end, precisely since you might have tried it if you considered necessary. These suggestions as well worked like a fantastic way to be sure that most people have the same fervor similar to my personal own to grasp much more around this problem. I think there are numerous more fun occasions in the future for people who look over your blog post.
I precisely wanted to say thanks again. I do not know the things I could possibly have tried in the absence of the tricks provided by you over such area. It was the daunting dilemma for me personally, nevertheless taking a look at a new well-written form you managed it forced me to leap over joy. I’m grateful for the information and thus believe you comprehend what an amazing job that you’re accomplishing educating many others via a site. I am certain you’ve never encountered all of us.
I would like to get across my respect for your generosity supporting persons that require guidance on this study. Your personal commitment to getting the solution all around had been amazingly informative and has in most cases helped individuals just like me to arrive at their endeavors. Your entire important help entails a lot to me and far more to my colleagues. Thank you; from each one of us.
I precisely wished to thank you so much all over again. I do not know what I might have used in the absence of the type of suggestions revealed by you relating to such area of interest. Entirely was an absolute difficult issue for me personally, however , observing your specialized avenue you handled it forced me to weep for fulfillment. I am just happy for the advice and as well , hope that you find out what an amazing job that you are doing teaching some other people through the use of your webpage. Probably you’ve never met all of us.
I have to point out my respect for your kind-heartedness giving support to folks who should have assistance with this important theme. Your very own dedication to getting the message all over has been astonishingly practical and have really allowed professionals just like me to reach their objectives. Your entire helpful guideline implies this much to me and further more to my peers. Regards; from each one of us.
Thank you a lot for providing individuals with an exceptionally spectacular chance to read critical reviews from this site. It really is so amazing plus jam-packed with amusement for me personally and my office colleagues to search your blog at least three times per week to see the fresh guidance you have. Not to mention, I’m always satisfied with your stunning tactics you serve. Some 4 tips in this post are honestly the most suitable I have had.
Thanks for each of your work on this website. My mum take interest in making time for investigations and it’s simple to grasp why. A number of us hear all regarding the lively mode you present powerful guidance on this web blog and therefore boost contribution from some other people on the matter so our daughter is without question studying a whole lot. Take advantage of the remaining portion of the new year. You are conducting a useful job.
My spouse and i have been really satisfied Albert managed to carry out his survey while using the ideas he discovered while using the blog. It’s not at all simplistic to just happen to be handing out helpful tips which many people may have been making money from. And we all acknowledge we now have the blog owner to give thanks to because of that. Those explanations you made, the simple website menu, the friendships you aid to instill – it’s everything fabulous, and it’s assisting our son in addition to us feel that the subject is interesting, and that’s very vital. Thanks for the whole thing!
I in addition to my guys came studying the great tactics found on the website while unexpectedly came up with a terrible feeling I never expressed respect to you for those secrets. Most of the young boys were totally passionate to see all of them and already have in truth been loving these things. I appreciate you for simply being considerably helpful as well as for opting for this kind of good areas millions of individuals are really eager to discover. Our sincere regret for not expressing gratitude to you sooner.
Thank you a lot for giving everyone such a nice possiblity to check tips from this site. It’s always very lovely and also packed with a lot of fun for me and my office peers to visit your website the equivalent of 3 times per week to read the newest tips you have got. And of course, I am usually satisfied considering the wonderful tactics you give. Selected 4 points in this article are indeed the most efficient I’ve ever had.
purchase arimidex pill purchase arimidex pill anastrozole usa