{"id":11641,"date":"2026-07-14T15:42:31","date_gmt":"2026-07-14T07:42:31","guid":{"rendered":"https:\/\/activatedcarbon.net\/?p=11641"},"modified":"2026-07-21T17:12:28","modified_gmt":"2026-07-21T09:12:28","slug":"activated-carbon-for-palladium-adsorption","status":"publish","type":"post","link":"https:\/\/activatedcarbon.net\/ru\/activated-carbon-for-palladium-adsorption\/","title":{"rendered":"Activated Carbon for Palladium Adsorption"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

Introduction<\/h2>\n\n\n\n

Palladium (Pd) is one of the most valuable precious metals on Earth \u2014 with prices consistently exceeding $2,000 per troy ounce. It is indispensable in automotive catalytic converters, electronics manufacturing, pharmaceutical synthesis, and chemical catalysis. As global demand soars and natural deposits deplete, recovering palladium from secondary sources \u2014 spent catalysts, electronic waste (e-waste), plating rinses, and refinery leach solutions \u2014 has become both an economic necessity and an environmental imperative.<\/p>\n\n\n\n

Among all recovery technologies, adsorption onto modified activated carbon stands out for its simplicity, selectivity, and cost-efficiency. At Zhulin Carbon, we produce coconut shell activated carbon impregnated with nitric acid (HNO\u2083) specifically engineered for high-capacity palladium adsorption from aqueous solutions. In this guide, we explain how it works, why nitric acid modification is critical, and what specifications you should look for.<\/p>\n\n\n\n

Why Is Palladium Recovery Important?<\/strong><\/h2>\n\n\n\n

Palladium belongs to the platinum group metals (PGMs), a family of six precious elements that are rare, difficult to mine, and strategically critical. The drivers for palladium recovery include:<\/p>\n\n\n\n

    \n
  • Automotive catalytic converters consume ~80% of global Pd supply; electronics, dentistry, and chemical catalysts account for most of the remainder.<\/li>\n\n\n\n
  • Over 75% of primary Pd comes from just two countries (Russia and South Africa). Geopolitical risks make supply unreliable.<\/li>\n\n\n\n
  • Printed circuit boards, mobile phones, and connectors contain 100\u20131,000 g\/ton of Pd \u2014 far richer than the 5\u201310 g\/ton found in mined ore.<\/li>\n\n\n\n
  • Urban mining of Pd from waste reduces the environmental footprint of mining, prevents toxic metal leaching into ecosystems, and supports circular economy goals.<\/li>\n\n\n\n
  • Even dilute solutions (10\u2013500 ppm Pd) represent significant value; efficient recovery directly impacts the bottom line.<\/li>\n<\/ul>\n\n\n\n

    Industrial palladium-bearing solutions typically arise from: spent Pd\/Al\u2082O\u2083 catalyst leaching (aqua regia or HCl\/Cl\u2082), electronics recycling acid leaching, electroplating rinse waters, and refinery raffinates. These solutions are often complex, containing competing base metals (Cu, Ni, Fe, Zn) alongside the target palladium.<\/p>\n\n\n\n

    How Activated Carbon Adsorbs Palladium<\/strong><\/h2>\n\n\n\n

    In acidic chloride solutions \u2014 the most common medium for Pd processing \u2014 palladium exists predominantly as the tetrachloropalladate(II) anion, [PdCl\u2084]\u00b2\u207b. The adsorption of this anion onto activated carbon involves multiple mechanisms:<\/p>\n\n\n\n

      \n
    • Oxygen-containing surface functional groups (particularly carboxyl \u2013COOH and phenolic \u2013OH) act as ion-exchange sites, releasing H\u207a and capturing [PdCl\u2084]\u00b2\u207b from solution.<\/li>\n\n\n\n
    • Surface oxygen groups form coordinate bonds with Pd\u00b2\u207a ions, creating stable surface complexes that lock the metal onto the carbon.<\/li>\n\n\n\n
    • The carbon surface can act as a mild reducing agent, converting Pd\u00b2\u207a to Pd\u2070 (metallic palladium nanoparticles) on the carbon surface. This is enhanced by the electron-donating capacity of the carbon lattice.<\/li>\n\n\n\n
    • The micropore network (<2 nm) of coconut shell carbon traps [PdCl\u2084]\u00b2\u207b ions and Pd-organic complexes through van der Waals forces and size exclusion.<\/li>\n\n\n\n
    • The graphitic basal planes of activated carbon interact with the d-orbitals of palladium species through electron donor-acceptor mechanisms.<\/li>\n<\/ul>\n\n\n\n

      Unmodified coconut shell carbon adsorbs Pd at moderate capacity. But when the carbon surface is oxidized with nitric acid, the density of carboxyl, lactone, and phenolic groups increases dramatically \u2014 boosting Pd adsorption capacity by 2\u20135 times.<\/p>\n\n\n\n

      \"\"<\/figure>\n\n\n\n

      Why Nitric Acid (HNO\u2083) Impregnation Is Appropriate<\/strong><\/h2>\n\n\n\n

      The key to high-performance palladium adsorption lies in the surface chemistry of the carbon. Untreated coconut shell carbon has a relatively hydrophobic, low-oxygen surface. Treatment with nitric acid achieves several critical modifications simultaneously:<\/p>\n\n\n\n

        \n
      • HNO\u2083 oxidizes the carbon surface, generating large numbers of \u2013COOH groups. These are the primary binding sites for [PdCl\u2084]\u00b2\u207b through ion exchange: R\u2013COOH + [PdCl\u2084]\u00b2\u207b \u2192 R\u2013COO\u2013PdCl\u2083 + HCl + Cl\u207b.<\/li>\n\n\n\n
      • Additional oxygen functional groups contribute to Pd complexation and improve wettability, allowing aqueous Pd solutions to penetrate the pore network more effectively.<\/li>\n\n\n\n
      • The total acidic group density on HNO\u2083-treated carbon can reach 1.5\u20133.0 mmol\/g, compared to 0.3\u20130.6 mmol\/g on untreated carbon \u2014 a 3\u20135x improvement in ion-exchange capacity.<\/li>\n\n\n\n
      • Mild HNO\u2083 treatment removes amorphous carbon deposits and tar residues from pore entrances, improving access to the micropore interior without destroying the pore structure.<\/li>\n\n\n\n
      • The oxygen-rich surface shows preferential affinity for soft Lewis acids like Pd\u00b2\u207a (a soft acid) over hard Lewis acids like Fe\u00b3\u207a, Cu\u00b2\u207a, and Ni\u00b2\u207a, enhancing selectivity in complex solutions.<\/li>\n<\/ul>\n\n\n\n

        The result: HNO\u2083-impregnated coconut shell carbon can achieve Pd adsorption capacities of 80\u2013200 mg Pd\/g carbon \u2014 far exceeding the 20\u201350 mg\/g typical of unmodified carbon.<\/p>\n\n\n\n

        Why Coconut Shell Carbon Is the Ideal Substrate<\/strong><\/h2>\n\n\n\n

        Among all activated carbon raw materials, coconut shell is the best substrate for precious metal adsorption for several reasons:<\/p>\n\n\n\n

          \n
        • Coconut shell carbon has >85% micropores (<2 nm), providing the highest surface area per gram (1,000\u20131,500 m\u00b2\/g). This maximizes the density of adsorption sites for Pd ions and complexes.<\/li>\n\n\n\n
        • The rigid structure of coconut shell carbon withstands acid treatment, repeated loading\/elution cycles, and mechanical handling without degradation \u2014 critical for industrial recovery operations.<\/li>\n\n\n\n
        • Minimal mineral content means fewer competing adsorption sites and less interference from soluble ash components in acidic Pd solutions.<\/li>\n\n\n\n
        • Coconut shells are an agricultural byproduct; their use supports sustainability and reduces carbon footprint compared to coal-based carbons.<\/li>\n\n\n\n
        • Steam activation of coconut shells produces a narrow, uniform micropore distribution ideal for trapping small Pd species (kinetic diameter of [PdCl\u2084]\u00b2\u207b ~5 \u00c5).<\/li>\n<\/ul>\n\n\n\n

          Technical Parameters of Our HNO\u2083-Impregnated Coconut Shell Carbon for Pd Adsorption<\/strong><\/h3>\n\n\n\n
          Parameter<\/strong><\/td>Unit<\/strong><\/td>Specification<\/strong><\/td>Why It Matters for Pd Adsorption<\/strong><\/td><\/tr>
          Raw Material<\/strong><\/td>\u2014<\/td>Premium coconut shell<\/td>High hardness, renewable, low ash<\/td><\/tr>
          Manufacturing Process<\/strong><\/td>\u2014<\/td>Steam activation \u2192 HNO\u2083 impregnation \u2192 Washing \u2192 Drying<\/td>Engineered surface chemistry for Pd capture<\/td><\/tr>
          Particle Size<\/strong><\/td>mesh<\/td>5\u00d710 <\/td>Select by column flow rate & bed design<\/td><\/tr>
          Iodine Number<\/strong><\/td>mg\/g<\/td>\u2265 1,000 \u2013 1,200<\/td>High micropore surface area<\/td><\/tr>
          Specific Surface Area (BET)<\/strong><\/td>m\u00b2\/g<\/td>\u2265 1,100 \u2013 1,500<\/td>Maximum adsorption sites for Pd species<\/td><\/tr>
          Total Pore Volume<\/strong><\/td>cm\u00b3\/g<\/td>\u2265 0.50<\/td>Adequate space for diffusion<\/td><\/tr>
          Micropore Volume (<2 nm)<\/strong><\/td>cm\u00b3\/g<\/td>\u2265 0.40<\/td>Micropore-dominated; ideal for Pd ion trapping<\/td><\/tr>
          Apparent \/ Bulk Density<\/strong><\/td>g\/cm\u00b3<\/td>0.45 \u2013 0.52<\/td>Optimized mass-per-volume<\/td><\/tr>
          Hardness \/ Abrasion Number<\/strong><\/td>%<\/td>\u2265 97<\/td>Survives acid treatment & repeated elution cycles<\/td><\/tr>
          Ash Content<\/strong><\/td>%<\/td>\u2264 5<\/td>Minimal mineral interference in acidic Pd solutions<\/td><\/tr>
          Moisture (as packed)<\/strong><\/td>%<\/td>\u2264 5<\/td>Maximum active carbon content<\/td><\/tr>
          Surface Oxygen Groups (Boehm)<\/strong><\/td>mmol\/g<\/td>\u2265 1.5 \u2013 3.0<\/td>High density of \u2013COOH, lactone, phenolic groups for Pd binding<\/td><\/tr>
          Carboxyl Group Density<\/strong><\/td>mmol\/g<\/td>\u2265 0.8 \u2013 1.5<\/td>Primary ion-exchange sites for [PdCl\u2084]\u00b2\u207b capture<\/td><\/tr>
          pH (aqueous extract)<\/strong><\/td>\u2014<\/td>3.0 \u2013 5.0 (acidic surface)<\/td>Acidic surface enhances Pd\u00b2\u207a selectivity over base metals<\/td><\/tr>
          CTC Adsorption<\/strong><\/td>% (wt)<\/td>\u2265 55 \u2013 60<\/td>Confirms well-developed pore structure<\/td><\/tr>
          Pd Adsorption Capacity<\/strong><\/td>mg Pd\/g<\/td>80 \u2013 200 (typical, lab-determined)<\/td>2\u20135\u00d7 higher than unmodified carbon<\/td><\/tr>
          Pd Selectivity (Pd vs Cu\/Ni\/Fe)<\/strong><\/td>\u2014<\/td>High (Kd > 10\u2074 for Pd)<\/td>Preferential Pd uptake from mixed-metal solutions<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

          How to Recover Palladium Using Modified Activated Carbon<\/strong><\/h2>\n\n\n\n

          A typical Pd recovery process using HNO\u2083-impregnated coconut shell carbon involves four main stages: adsorption, elution, regeneration, and metal refining.<\/p>\n\n\n\n

          1. Solution preparation: <\/strong>Adjust the Pd-bearing leach solution to the optimal pH (typically pH 1\u20133 in HCl medium) and chloride concentration (0.5\u20132 M Cl\u207b). Pre-filter to remove suspended solids. If competing metals are present at very high concentrations, consider a selective precipitation or solvent extraction pre-treatment.<\/p>\n\n\n\n

          2. Adsorption (column or batch): <\/strong>Column mode: Pass the solution through a fixed bed of HNO\u2083-impregnated carbon at a flow rate giving 10\u201330 minutes EBCT. Monitor Pd breakthrough at the outlet. Batch mode: Add carbon at 1\u201310 g\/L dosage, stir for 2\u20136 hours, then filter. Typical Pd removal: >95% in single pass.<\/p>\n\n\n\n

          3. Elution (stripping): <\/strong>Strip adsorbed Pd from the loaded carbon using a strong eluant: (a) acidic thiourea solution (1\u20135% thiourea in 0.1\u20131 M HCl), or (b) ammoniacal solution (5\u201310% NH\u2083). Thiourea achieves >98% Pd recovery in a single elution. The concentrated eluate is sent for Pd precipitation or electrowinning.<\/p>\n\n\n\n

          4. Carbon regeneration: <\/strong>After 3\u20135 adsorption-elution cycles, regenerate the carbon thermally (700\u2013800 \u00b0C under steam\/N\u2082) or re-impregnate with HNO\u2083 to restore surface oxygen groups. Coconut shell carbon’s high hardness allows 5\u201310 regeneration cycles before replacement.<\/p>\n\n\n\n

          5. Pd refining: <\/strong>Precipitate Pd from the eluate as (NH\u2084)\u2082PdCl\u2086 using NH\u2084Cl, or reduce directly to Pd sponge with hydrazine or formic acid. The final Pd product purity: \u226599.9%.<\/p>\n\n\n\n

          Where Is This Technology Applied?<\/strong><\/h2>\n\n\n\n
            \n
          • Spent automotive catalyst recycling \u2014 leaching Pd from ceramic honeycomb substrates<\/li>\n\n\n\n
          • Electronics and e-waste recycling \u2014 recovering Pd from PCB leach solutions and connector scrap<\/li>\n\n\n\n
          • Chemical and pharmaceutical catalyst recovery \u2014 Pd\/C catalyst regeneration streams<\/li>\n\n\n\n
          • Electroplating industry \u2014 Pd recovery from plating bath rinses and drag-out tanks<\/li>\n\n\n\n
          • Petroleum refining \u2014 Pd-containing catalyst treatment and leachate processing<\/li>\n\n\n\n
          • Precious metal refineries \u2014 polishing Pd from tailings and barren solutions<\/li>\n\n\n\n
          • Analytical laboratories \u2014 Pd pre-concentration for trace analysis<\/li>\n\n\n\n
          • Jewelry manufacturing \u2014 Pd recovery from polishing sludges and waste solutions<\/li>\n<\/ul>\n\n\n\n

            Why Choose Zhulin Carbon for Palladium Recovery?<\/strong><\/h2>\n\n\n\n

            Zhulin Carbon understands that precious metal recovery demands carbon of the highest purity, consistency, and engineered surface chemistry. Here is what sets us apart:<\/p>\n\n\n\n

              \n
            • Our proprietary acid-treatment process creates a precisely engineered surface oxygen group profile, maximizing carboxyl density (\u22650.8\u20131.5 mmol\/g) for maximum Pd binding capacity.<\/li>\n\n\n\n
            • We select only high-quality coconut shells from tropical plantations, ensuring consistently high hardness (\u226597%) and low ash (\u22645%).<\/li>\n\n\n\n
            • Lab-tested Pd adsorption capacity of 80\u2013200 mg\/g, verified under realistic industrial conditions (pH 1\u20133, HCl\/Cl\u207b medium).<\/li>\n\n\n\n
            • Strict QC protocol: every batch tested for iodine number, BET surface area, hardness, ash, and Boehm titration of surface oxygen groups.<\/li>\n\n\n\n
            • Our metallurgy team can run lab-scale adsorption isotherms and column tests on your specific Pd solution to optimize dosage and process parameters.<\/li>\n\n\n\n
            • We offer re-impregnation services to restore surface chemistry after multiple elution cycles, extending carbon lifespan and reducing costs.<\/li>\n\n\n\n
            • 5\u00d710, 6\u00d712, or custom; 1 kg \/ 5 kg \/ 25 kg bags or super sacks. Secure packaging for international shipping.<\/li>\n<\/ul>\n\n\n\n

              Conclusion<\/strong><\/h2>\n\n\n\n

              Palladium recovery is one of the highest-value applications of activated carbon technology. HNO\u2083-impregnated coconut shell activated carbon \u2014 with its engineered surface oxygen chemistry, superior micropore structure, exceptional hardness, and high Pd selectivity \u2014 delivers adsorption capacities of 80\u2013200 mg Pd\/g, making it the most cost-effective solution for recovering this strategic precious metal from spent catalysts, e-waste, plating solutions, and refinery streams. With Zhulin Carbon’s specialized grades and metallurgical expertise, recyclers and refiners can maximize Pd recovery while minimizing operating costs.<\/p>\n\n\n\n

              Ready to boost your palladium recovery efficiency? Contact our technical team at info@activatedcarbon.net or call +86-19949132731 for free samples, lab-scale adsorption testing on your solution, and expert process design support.<\/p>\n","protected":false},"excerpt":{"rendered":"

              Introduction Palladium (Pd) is one of the most valuable precious metals on Earth \u2014 with prices consistently exceeding $2,000 per troy ounce. It is indispensable in automotive catalytic converters, electronics manufacturing, pharmaceutical synthesis, and chemical catalysis. As global demand soars and natural deposits deplete, recovering palladium from secondary sources \u2014 spent catalysts, electronic waste (e-waste), […]<\/p>\n","protected":false},"author":1,"featured_media":11671,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","footnotes":""},"categories":[76],"tags":[],"class_list":["post-11641","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-activated-carbon-manufacturers"],"uagb_featured_image_src":{"full":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption.png",840,450,false],"thumbnail":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption-150x150.png",150,150,true],"medium":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption-300x161.png",300,161,true],"medium_large":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption-768x411.png",768,411,true],"large":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption.png",800,429,false],"1536x1536":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption.png",840,450,false],"2048x2048":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption.png",840,450,false],"trp-custom-language-flag":["https:\/\/activatedcarbon.net\/wp-content\/uploads\/2026\/07\/Activated-Carbon-for-Palladium-Adsorption-18x10.png",18,10,true]},"uagb_author_info":{"display_name":"zhulincarbon","author_link":"https:\/\/activatedcarbon.net\/ru\/author\/zhulincarbon\/"},"uagb_comment_info":0,"uagb_excerpt":"Introduction Palladium (Pd) is one of the most valuable precious metals on Earth \u2014 with prices consistently exceeding $2,000 per troy ounce. It is indispensable in automotive catalytic converters, electronics manufacturing, pharmaceutical synthesis, and chemical catalysis. As global demand soars and natural deposits deplete, recovering palladium from secondary sources \u2014 spent catalysts, electronic waste (e-waste),…","_links":{"self":[{"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/posts\/11641","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/comments?post=11641"}],"version-history":[{"count":0,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/posts\/11641\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/media\/11671"}],"wp:attachment":[{"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/media?parent=11641"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/categories?post=11641"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/activatedcarbon.net\/ru\/wp-json\/wp\/v2\/tags?post=11641"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}