{"id":247,"date":"2025-09-20T12:04:51","date_gmt":"2025-09-20T12:04:51","guid":{"rendered":"https:\/\/tarabideh.com\/en\/?p=247"},"modified":"2025-09-20T12:04:51","modified_gmt":"2025-09-20T12:04:51","slug":"nanofiltration-for-arsenic-and-hardness-removal","status":"publish","type":"post","link":"https:\/\/tarabideh.com\/en\/2025\/09\/20\/nanofiltration-for-arsenic-and-hardness-removal\/","title":{"rendered":"NanoFiltration for Arsenic and Hardness Removal"},"content":{"rendered":"

\"\"<\/h1>\n

<\/h1>\n

Application of Nanofiltration in Arsenic Removal and Groundwater Hardness Reduction<\/span><\/h1>\n

Nanofiltration (NF), as one of the advanced membrane technologies, has gained a prominent position in the treatment of groundwater contaminated with arsenic and hardness-causing ions.<\/p>\n

Compared to reverse osmosis (RO), NF offers significant advantages due to its lower operating pressure, reduced energy consumption, and selective contaminant removal.<\/p>\n

Case Study: Arsenic and Hardness Removal in a Municipal Water Treatment Plant<\/span><\/h2>\n

In a pilot project, the use of polyamide NF90 membranes combined with microfiltration pretreatment produced highly promising results:<\/p>\n

    \n
  • Arsenic reduction:<\/strong> from ~80 \u00b5g\/L to <10 \u00b5g\/L (meeting WHO guidelines).<\/li>\n
  • Total hardness reduction:<\/strong> from 1500 mg\/L to ~400 mg\/L.<\/li>\n
  • Energy consumption:<\/strong> as low as 0.9 kWh\/m\u00b3.<\/li>\n
  • Recovery rate:<\/strong> 82%.<\/li>\n<\/ul>\n

    These findings demonstrate that nanofiltration can simultaneously improve drinking water quality and lower operational costs.<\/p>\n

    Operating and Design Conditions<\/span><\/strong><\/h2>\n

    A practical test was conducted on groundwater with the following parameters:<\/p>\n

      \n
    • Influent arsenic:<\/strong> 50\u2013100 \u00b5g\/L<\/li>\n
    • Hardness:<\/strong> 1500 mg\/L<\/li>\n
    • pH:<\/strong> ~7.5<\/li>\n<\/ul>\n

      Treatment process:<\/span><\/strong><\/h3>\n
        \n
      1. Microfiltration (0.1 \u00b5m)<\/strong> for suspended solids removal.<\/li>\n
      2. Chlorine dosing (1 mg\/L)<\/strong> to oxidize As(III) into As(V).<\/li>\n
      3. NF90 membranes<\/strong> with pore size of 1\u20132 nm.<\/li>\n
      4. Operating conditions:<\/strong> pressure 10\u201312 bar, temperature 22\u201325 \u00b0C, flowrate 1.2 L\/min, recovery 82%.<\/li>\n
      5. Regular chemical cleaning<\/strong> (acidic and alkaline) extended membrane life up to 4 years.<\/li>\n<\/ol>\n

        Performance Results<\/span><\/strong><\/h2>\n
          \n
        • Arsenic removal:<\/strong> ~90% (final concentration 8 \u00b5g\/L).<\/li>\n
        • Hardness reduction:<\/strong> 65% (from 1500 \u2192 400 mg\/L).<\/li>\n
        • TDS reduction:<\/strong> from 1500 \u2192 400 mg\/L.<\/li>\n
        • Energy consumption:<\/strong> 60\u201370% lower than RO.<\/li>\n<\/ul>\n

          Comparison with Reverse Osmosis (RO)<\/strong><\/span><\/h2>\n

          Advantages of NF over RO:<\/strong><\/p>\n

            \n
          • Lower operating pressure (10\u201320 bar vs. 20\u201380 bar).<\/li>\n
          • Selective removal of contaminants while retaining beneficial minerals (e.g., potassium).<\/li>\n
          • Reduced energy demand and lower operating costs.<\/li>\n
          • Higher drinking water quality (no remineralization required).<\/li>\n<\/ul>\n

            Design and Operational Insights<\/span><\/strong><\/h2>\n
              \n
            • Optimum performance was achieved at ~10 bar and near-neutral pH (6\u20137)<\/strong>.<\/li>\n
            • As(V) removal >95%<\/strong>, while As(III) requires prior oxidation (chlorine, ozone, KMnO\u2084).<\/li>\n
            • Pressures >12 bar increased energy use and fouling without significant removal improvement.<\/li>\n
            • Shifting pH above 8 or below 6 reduced arsenic removal efficiency.<\/li>\n<\/ul>\n

              Practical Importance<\/span><\/strong><\/h2>\n

              Given the ongoing water crisis in Iran, the development and implementation of NF-based treatment and reuse systems can play a key role in providing safe and sustainable drinking water. Successful experiences in countries like Israel (e.g., Shafdan and Sorek projects) highlight how proper investment and management in this field can improve water quality while reducing national costs.<\/p>\n

              Reference and Experimental Results<\/span><\/strong><\/h2>\n

              [1]<\/strong> Siddique TA, Dutta NK, Choudhury NR. Nanofiltration for arsenic removal: Challenges, recent developments, and perspectives.<\/em> Nanomaterials. 2020;10(7):1323.<\/p>\n

              NF Test Results for Arsenic Removal<\/span><\/strong><\/h3>\n\n\n\n\n\n\n\n\n\n\n\n\n\n
              Technical Notes<\/strong><\/td>\nOxidation Required?<\/strong><\/td>\nAs(III) Removal (%)<\/strong><\/td>\nAs(V) Removal (%)<\/strong><\/td>\nRecovery (%)<\/strong><\/td>\npH<\/strong><\/td>\nFeed Pressure (bar)<\/strong><\/td>\n<\/tr>\n<\/thead>\n
              As(III) weakly removed \u2013 only As(V) efficiently rejected at neutral pH<\/td>\nYes<\/td>\n37<\/td>\n82<\/td>\n65<\/td>\n6<\/td>\n4<\/td>\n<\/tr>\n
              Higher pressure improves retention, especially As(V)<\/td>\nYes<\/td>\n44<\/td>\n90<\/td>\n70<\/td>\n6<\/td>\n6<\/td>\n<\/tr>\n
              Very good As(V) removal, As(III) still low<\/td>\nYes<\/td>\n48<\/td>\n95<\/td>\n77<\/td>\n6<\/td>\n8<\/td>\n<\/tr>\n
              Optimum point \u2013 high TMP, good recovery<\/td>\nYes<\/td>\n52<\/td>\n97<\/td>\n82<\/td>\n6<\/td>\n10<\/td>\n<\/tr>\n
              Removal stable for As(V), As(III) slightly better but fouling begins<\/td>\nYes<\/td>\n54<\/td>\n97.5<\/td>\n85<\/td>\n6<\/td>\n12<\/td>\n<\/tr>\n
              Higher pH \u2192 lower removal of both As(V) & As(III)<\/td>\nYes<\/td>\n46<\/td>\n94<\/td>\n80<\/td>\n8<\/td>\n10<\/td>\n<\/tr>\n
              Strongly alkaline \u2192 further drop due to deprotonation<\/td>\nYes<\/td>\n41<\/td>\n90<\/td>\n78<\/td>\n10<\/td>\n10<\/td>\n<\/tr>\n
              Acidic pH \u2192 lower removal, surface charge effect<\/td>\nYes<\/td>\n32<\/td>\n78<\/td>\n60<\/td>\n4<\/td>\n4<\/td>\n<\/tr>\n
              Acidic + moderate pressure \u2192 slightly better but still weak<\/td>\nYes<\/td>\n35<\/td>\n84<\/td>\n63<\/td>\n4<\/td>\n6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

              <\/h2>\n

              <\/h2>\n

              Key Technical Notes for NF in Arsenic Removal<\/span><\/strong><\/h2>\n
                \n
              • As(V):<\/strong> removal up to 97\u201398% at 10\u201312 bar.<\/span><\/li>\n
              • As(III):<\/strong> poorly removed (<55%), must be oxidized to As(V) beforehand.<\/span><\/li>\n
              • Optimum removal and recovery at 10 bar, ~80\u201382% recovery, pH 6\u20137<\/strong>.<\/span><\/li>\n
              • pH <6 or >8 reduces efficiency for both As(V) and As(III).<\/span><\/li>\n
              • Higher pressures (>12 bar) \u2192 more fouling and energy demand, without significant benefit.<\/span><\/li>\n
              • Design takeaway:<\/strong> oxidation pretreatment + optimum feed pressure + pH control are essential for reliable NF arsenic removal.<\/span><\/li>\n<\/ul>\n

                 <\/p>\n","protected":false},"excerpt":{"rendered":"

                Application of Nanofiltration in Arsenic Removal and Groundwater Hardness Reduction Nanofiltration (NF), as one of the advanced membrane technologies, has […]<\/p>\n","protected":false},"author":1,"featured_media":248,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[30],"tags":[],"class_list":["post-247","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-articles"],"_links":{"self":[{"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/posts\/247","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/comments?post=247"}],"version-history":[{"count":1,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/posts\/247\/revisions"}],"predecessor-version":[{"id":249,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/posts\/247\/revisions\/249"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/media\/248"}],"wp:attachment":[{"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/media?parent=247"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/categories?post=247"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tarabideh.com\/en\/wp-json\/wp\/v2\/tags?post=247"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}