THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), AND MAY NOT BE OFFERED, SOLD,
PLEDGED, HYPOTHECATED, ASSIGNED OR TRANSFERRED EXCEPT (i) PURSUANT TO A
REGISTRATION STATEMENT UNDER THE ACT WHICH HAS BECOME EFFECTIVE AND IS CURRENT
WITH RESPECT TO SUCH SECURITIES, OR (ii) PURSUANT TO A SPECIFIC EXEMPTION FROM
REGISTRATION UNDER THE ACT BUT ONLY UPON A HOLDER HEREOF FIRST HAVING OBTAINED
THE WRITTEN OPINION OF COUNSEL TO THE COMPANY, OR OTHER COUNSEL REASONABLY
ACCEPTABLE TO THE COMPANY, THAT THE PROPOSED DISPOSITION IS CONSISTENT WITH ALL
APPLICABLE PROVISIONS OF THE ACT AS WELL AS ANY APPLICABLE "BLUE SKY" OR SIMILAR
STATE SECURITIES LAW.

                   CONVERSION TECHNOLOGIES INTERNATIONAL, INC.

                CONVERTIBLE PROMISSORY NOTE DUE SEPTEMBER 1, 1999

                                                                    ______, 1999

      FOR VALUE RECEIVED, Conversion Technologies International, Inc., a
Delaware corporation (the "Company"), hereby promises to pay to The Aries Master
Fund, a Cayman Island Exempted Company or its registered assigns (the "Holder"),
the principal amount of __________________ Dollars ($_______) (the "Principal
Amount"), and to pay interest thereon at the rate of 12% per annum. Principal
and accrued interest shall be due and payable on the Maturity Date (as defined
in Section 1 hereof) unless this Note is converted in accordance with Section 2
hereof. Payments will be made to the office of Maker in lawful money of the
United States of America. All references to dollars are to U.S. dollars.

            1. Maturity. Unless converted in accordance with Section 2 hereof,
the Principal Amount of this Note, together with accrued interest thereon, shall
be due and payable on the earlier of (i) September 1, 1999, or (ii) the
completion of equity financings or other transactions that generate an aggregate
amount equal to or greater than $2,790,000 for the Company (the "Maturity
Date").

            2. Optional Conversion. Upon the occurrence of the Conversion Event
(as defined below), the Principal Amount of, and accrued and unpaid interest on
this Note, at the option of the Holder, is subject to conversion into equity
securities ("Equity Securities") of either (i) the Company or (ii) Advanced
Particle Technologies, Inc., a Delaware corporation and a wholly-owned
subsidiary of the Company ("APT"), subject to the terms and conditions set forth
in Sections 2(a) - (e) hereof. The "Conversion Event" shall mean either (i) the
failure of the Company to raise an aggregate of $1,500,000 by April 1, 1999,
through the closing of an equity offering or otherwise or (ii) an Event of
Default as such term is defined in Section 4 hereof. Notwithstanding the first
sentence hereof, if the Conversion Event occurs, on or subsequent to April 1,
1999 all, but not less than all, of the outstanding Principal Amount of, and
accrued interest on this Note, may, at the discretion of the Holder, be
converted into Equity Securities of

<PAGE>

the Company or exchanged for Equity Securities of APT, subject to the terms and
conditions set forth in Section 2(a) - (e) hereof.

            (a) Conversion into Company Shares. In the event that the Holder
exercises its option to convert the outstanding Principal Amount, and the
accrued and unpaid interest on this Note, into shares of the Equity Securities
of the Company, the number of Equity Securities into which this Note shall or
may be converted, as the case may be, shall be determined by dividing the sum of
the Principal Amount plus the accrued and unpaid interest on this Note by the
Conversion Price (as defined in this Section 2(a)). Upon such conversion, the
Principal Amount of, and accrued interest on, this Note shall be discharged. The
"Conversion Price," when determined, will be equal to the thirty day moving
average of the price per share, as quoted on the Pink Sheets(R), a quotation
medium operated by the National Quotation Bureau, LLC, of the Equity Securities
of the Company for the thirty day period immediately preceding the date of
conversion.

            (b) Exchange into APT Shares. In the event that the Holder exercises
its option to exchange the outstanding Principal Amount, and the accrued and
unpaid interest on this Note, into shares of APT, the number of Equity
Securities into which this Note shall or may be exchanged, as the case may be,
shall be equal to 10% of the issued and outstanding shares of the common stock
of APT, par value $.01 per share, as of the date of such exercise. Upon such
exchange, the Principal Amount of, and accrued interest on, this Note shall be
discharged.

            (c) Method of Conversion; Issuance of Underlying Securities. The
Company shall, following the occurrence of the Conversion Event and upon
presentment by the Holder of this Note to the Company, promptly issue and
deliver to the Holder certificates for the appropriate number of securities to
which the Holder shall be entitled as aforesaid.

            (d) Merger. In case of any consolidation or merger of the Company
with any other corporation, limited liability company or any other entity (each
such transaction, a "Merger"), the corporation formed by the Merger shall
succeed to the obligations, covenants, stipulations, promises and the agreements
contained in this Note. In the event of a Merger, the Company shall make
appropriate provisions so that the Holder shall have the right thereafter to
convert this Note into the kind and amount of securities receivable upon such
Merger by a Holder of a number of securities into which this Note might have
been converted upon the Holder's election under either Section 2(a) or 2(b)
hereof had it been so converted immediately prior to a Merger. The above
provisions shall similarly apply to successive Mergers.

            (e) Elimination of Fractional Interests. Neither the Company nor APT
shall be required to issue certificates representing fractions of Equity
Securities on the conversion of this Note, nor shall it be required to issue
scrip or pay cash in lieu of fractional interests, it being the intent of the
parties that all fractional interests shall be rounded to the nearest whole
share or security upon conversion of this Note directly into Equity Securities.


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<PAGE>

            3. Prepayment. The Company may at any time, upon thirty (30) days
prior written notice to the Holder, prepay in whole or part the principal sum,
plus accrued interest to date of payment, of this Note, without penalty or
premium. All sums paid hereon shall be applied first to accrued but unpaid
interest on this Note and the balance, if any, to the reduction of the principal
hereof. This Note shall not be due and payable until the Maturity Date. Once the
Maturity Date has been reached, all amounts evidenced by this Note shall be due
and payable.

            4. Events of Default. Each of the following shall constitute an
"Event of Default" under this Note:

            (a) The Company shall fail to pay any amount under this Note when
the same shall become due and payable, whether at maturity or by acceleration or
otherwise;

            (b) (i) the Company shall commence any action (a) under any law
relating to bankruptcy, insolvency, reorganization or relief of debtors, seeking
to have an order for relief entered with respect to the Company or its debts; or
(b) seeking appointment of a custodian, receiver or similar official for the
Company or any substantial part of its property; or (ii) any action of a nature
referred to above shall be commenced against the Company and results in an order
for relief or is not dismissed, discharged or fully bonded within 30 days; or
(iii) there shall be commenced against the Company any action seeking
attachment, execution or similar process against any substantial part of the
Company's property, which action is not within 30 days discharged or stayed or
fully bonded; or (iv) the Company shall, by act or omission, indicate its
consent to or acquiescence in any of the foregoing, without regard to the grace
periods set forth above; or (v) the Company shall be unable, or admit in writing
inability, to pay the Company's debts as they become due; or (vi) the Company
shall transfer or conceal its property with intent to hinder, delay or defraud
any creditors or to benefit any class of creditors or creditors generally or
shall suffer for 30 days or longer while insolvent any lien on the Company's
property resulting from judicial proceedings; and

            (c) the dissolution or other winding up of the Company.

            5. Remedies upon Events of Default. Upon the occurrence of an Event
of Default:

            (a) the entire principal amount of, and all accrued and unpaid
interest on, this Note shall automatically become immediately due and payable
without presentment, demand, protest or other formalities of any kind, all of
which are expressly waived by the Company;

            (b) additional interest shall begin to accrue, and shall be
considered immediately due and payable, on the unpaid principal amount of this
Note at the rate of 18% per annum and shall continue to accrue until the initial
interest and additional interest is paid; and

            (c) the Holder may take any action available to it hereunder or at
law or in equity or by statute or otherwise, including, without limitation, the
right to foreclosure on assets or convert into shares of the common stock of the
Company or exchange for shares of the common stock of APT.


                                       3
<PAGE>

            6. Representations. The Company hereby represents and warrants that
(i) it holds all of the issued and outstanding capital stock of APT and (ii) in
the event that the Holder exercises its option pursuant to Section 2(b) hereof,
receiving 10% of the issued and outstanding common stock of APT, and that it
exercises its Repayment Right pursuant to Section 2(a)(ii) of each of a series
of 12% Senior Secured Notes in the aggregate principal amount of $1,290,000 made
by the Company in favor of the Holder, receiving 90% of the issued and
outstanding common stock of APT, that the Holder will hold all of the capital
stock outstanding of APT and that the Company will not retain any such shares of
the capital stock of APT. The Company further represents and warrants that there
is outstanding no security or other instrument which by its terms is convertible
into or exchangeable for capital stock of APT.

            7. Miscellaneous.

            (a) Except as otherwise hereinabove expressly provided, upon an
Event of Default the Company hereby waives diligence, demand, protest,
presentment and all notices (whether of nonpayment, dishonor, protest,
acceleration or otherwise) and consents to acceleration of the time of payment
and to surrender, substitution or any other action or inaction with respect to
security and to forbearance and to other indulgence, all without notice. Failure
of Holder to assert any right herein shall not be deemed a waiver thereof.

            (b) This Note may be endorsed or assigned in whole or in part by
Holder without the consent of Maker.

            (c) This Note shall be governed by and construed in accordance with
the laws of the State of New York applicable to contracts made and to be
performed wholly within such State.

      IN WITNESS WHEREOF, the Company has caused this Note to be executed and
delivered by its duly authorized representative as of the date first written
above.

                                    CONVERSION TECHNOLOGIES
                                       INTERNATIONAL, INC.


                                    By: __________________________________
                                        Name:
                                        Title:


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